Vincristine-sulphate-loaded liposome-templated calcium phosphate nanoshell as potential tumor-targeting delivery system.

PubMed

Thakkar, Hetal Paresh; Baser, Amit Kumar; Parmar, Mayur Prakashbhai; Patel, Ketul Harshadbhai; Ramachandra Murthy, Rayasa

2012-06-01

Vincristine-sulfate-loaded liposomes were prepared with an aim to improve stability, reduce drug leakage during systemic circulation, and increase intracellular uptake. Liposomes were prepared by the thin-film hydration method, followed by coating with calcium phosphate, using the sequential addition approach. Prepared formulations were characterized for size, zeta potential, drug-entrapment efficiency, morphology by transmission electron microscopy (TEM), in vitro drug-release profile, and in vitro cell cytotoxicity study. Effect of formulation variables, such as drug:lipid ratio as well as nature and volume of hydration media, were found to affect drug entrapment, and the concentration of calcium chloride in coating was found to affect size and coating efficiency. Size, zeta potential, and TEM images confirmed that the liposomes were effectively coated with calcium phosphate. The calcium phosphate nanoshell exhibited pH-dependent drug release, showing significantly lower release at pH 7.4, compared to the release at pH 4.5, which is the pH of the tumor interstitium. The in vitro cytotoxicity study done on the lung cancer cell line indicated that coated liposomes are more cytotoxic than plain liposomes and drug solution, indicating their potential for intracellular drug delivery. The cell-uptake study done on the lung cancer cell line indicated that calcium-phosphate-coated liposomes show higher cell uptake than uncoated liposomes.

Gamma-oryzanol-loaded calcium pectinate microparticles reinforced with chitosan: optimization and release characteristics.

PubMed

Lee, Ji-Soo; Kim, Jong Soo; Lee, Hyeon Gyu

2009-05-01

Response surface methodology was used to optimize microparticle preparation conditions, including the ratio of pectin:gamma-oryzanol (OZ) (X(1)), agitation speed (X(2)), and the concentration of emulsifier (X(3)), for maximal entrapment efficiency (EE) of OZ-loaded Ca pectinate microparticles. The optimized values of X(1), X(2), and X(3) were found to be 2.72:5.28, 1143.5 rpm, and 2.61%, respectively. Experimental results obtained for the optimum formulation agreed favorably with the predicted results, indicating the usefulness of predicting models for EE. In order to evaluate the effect of chitosan-coating and blending on the release pattern of the entrapped OZ from microparticles, chitosan-coated and blended Ca pectinate microparticles were prepared. Release studies revealed that the chitosan treatments, especially the chitosan-coating, were effective in suppressing the release in both simulated gastric fluid (SGF) and intestinal fluid (SIF).

Relative bioavailability of 13C5-folic acid in pectin-coated folate fortified rice in humans using stable isotope techniques.

PubMed

de Ambrosis, A; Vishnumohan, S; Paterson, J; Haber, P; Arcot, J

2017-01-01

The aim of the study was to measure the relative bioavailability of labeled pteroylglutamic acid (13C5-PteGlu) from a pectin-coated fortified rice in vivo to measure any effect of the edible coating on folic acid bioavailability. Healthy volunteers (N=26) aged 18-39 years received three test meals in three randomized short-term cross-over trials: Trial 1: aqueous 400 μg 13C5-PteGlu, Trial 2: 200 g cooked white rice+400 μg 13C5-PteGlu,Trial 3: 200 g fortified cooked white rice with pectin-coated premix containing 400 μg 13C5-PteGlu. Blood samples were drawn at 0,1,2,5 and 8 h postprandial. The concentration of 13C5-5 methyl-tetrahydrofolate appearing in plasma was quantified using high performance liquid chromatography-mass spectrometry (MS)/MS. For 24 h before baseline estimation and during the area under the curve (AUC) study, the subjects were placed on a low folate diet (∼100 μg/day). The relative bioavailability of the folic acid following Trial 3 was measured by comparing the 13C5-5 methyl-tetrahydrofuran (THF) AUC with Trials 1 and 2. The bioavailability of folic acid in a pectin-coated rice premix was 68.7% (range 47-105) and 86.5% (range 65-115) in uncoated fortified rice relative to aqueous folic acid. This study is the first demonstration of the bioavailability of folate in pectin-coated fortified rice in humans.

Development of coated liposomes loaded with ghrelin for nose-to-brain delivery for the treatment of cachexia.

PubMed

Salade, Laurent; Wauthoz, Nathalie; Deleu, Magali; Vermeersch, Marjorie; De Vriese, Carine; Amighi, Karim; Goole, Jonathan

2017-01-01

The aim of the present study was to develop a ghrelin-containing formulation based on liposomes coated with chitosan intended for nose-brain delivery for the treatment of cachexia. Among the three types of liposomes developed, anionic liposomes provided the best results in terms of encapsulation efficiency (56%) and enzymatic protection against trypsin (20.6% vs 0% for ghrelin alone) and carboxylesterase (81.6% vs 17.2% for ghrelin alone). Ghrelin presented both electrostatic and hydrophobic interactions with the anionic lipid bilayer, as demonstrated by isothermal titration calorimetry. Then, anionic liposomes were coated with N -(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride. The coating involved a size increment from 146.9±2.7 to 194±6.1 nm, for uncoated and coated liposomes, respectively. The ζ-potential was similarly increased from -0.3±1.2 mV to 6±0.4 mV before and after coating, respectively. Chitosan provided mucoadhesion, with an increase in mucin adsorption of 22.9%. Enhancement of permeation through the Calu3 epithelial monolayer was also observed with 10.8% of ghrelin recovered in the basal compartment in comparison to 0% for ghrelin alone. Finally, aerosols generated from two nasal devices (VP3 and SP270) intended for aqueous dispersion were characterized with either coated or uncoated liposomes. Contrarily to the SP270 device, VP3 device showed minor changes between coated and uncoated liposome aerosols, as shown by their median volume diameters of 38.4±5.76 and 37.6±5.74 µm, respectively. Overall, the results obtained in this study show that the developed formulation delivered by the VP3 device can be considered as a potential candidate for nose-brain delivery of ghrelin.

Development of coated liposomes loaded with ghrelin for nose-to-brain delivery for the treatment of cachexia

PubMed Central

Salade, Laurent; Wauthoz, Nathalie; Deleu, Magali; Vermeersch, Marjorie; De Vriese, Carine; Amighi, Karim; Goole, Jonathan

2017-01-01

The aim of the present study was to develop a ghrelin-containing formulation based on liposomes coated with chitosan intended for nose–brain delivery for the treatment of cachexia. Among the three types of liposomes developed, anionic liposomes provided the best results in terms of encapsulation efficiency (56%) and enzymatic protection against trypsin (20.6% vs 0% for ghrelin alone) and carboxylesterase (81.6% vs 17.2% for ghrelin alone). Ghrelin presented both electrostatic and hydrophobic interactions with the anionic lipid bilayer, as demonstrated by isothermal titration calorimetry. Then, anionic liposomes were coated with N-(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride. The coating involved a size increment from 146.9±2.7 to 194±6.1 nm, for uncoated and coated liposomes, respectively. The ζ-potential was similarly increased from -0.3±1.2 mV to 6±0.4 mV before and after coating, respectively. Chitosan provided mucoadhesion, with an increase in mucin adsorption of 22.9%. Enhancement of permeation through the Calu3 epithelial monolayer was also observed with 10.8% of ghrelin recovered in the basal compartment in comparison to 0% for ghrelin alone. Finally, aerosols generated from two nasal devices (VP3 and SP270) intended for aqueous dispersion were characterized with either coated or uncoated liposomes. Contrarily to the SP270 device, VP3 device showed minor changes between coated and uncoated liposome aerosols, as shown by their median volume diameters of 38.4±5.76 and 37.6±5.74 µm, respectively. Overall, the results obtained in this study show that the developed formulation delivered by the VP3 device can be considered as a potential candidate for nose–brain delivery of ghrelin. PMID:29238190

Fabrication and characterization of silk fibroin-coated liposomes for ocular drug delivery.

PubMed

Dong, Yixuan; Dong, Pin; Huang, Di; Mei, Liling; Xia, Yaowen; Wang, Zhouhua; Pan, Xin; Li, Ge; Wu, Chuanbin

2015-04-01

The unique structure and protective mechanisms of the eye result in low bioavailability of ocular drugs. Using a mucoadhesive material is an efficient solution to improve ocular drug therapeutic efficacy. This study was designed to prepare a liposomal formulation coated by a novel adhesive excipient, silk fibroin (SF), for topical ocular drug delivery. The regenerated silk fibroins (SFs) with different dissolving time were coated onto the ibuprofen-loaded liposomes. The morphology, drug encapsulation efficiency, in vitro release and in vitro corneal permeation of SF-coated liposomes (SLs) were investigated in comparison with the conventional liposome. Cellular adhesion and cytotoxicity assay of SF and SLs were tested using human corneal epithelial cells (HCEC). SLs showed sustained drug release and in vitro corneal permeation of ibuprofen as compared to drug solution and conventional liposome. The cellular fluorescence appeared after 7 min of exposure to SF, and the intensity increased sustainedly up to 12h with no detectable cytotoxicity. Higher fluorescence intensity of Nile red in SLs was observed in a short period of 15 min showing a rapid uptake. These favorable properties make SF-coated liposome be a promising ocular drug delivery system. Copyright © 2015 Elsevier B.V. All rights reserved.

Eudragit® S100 coated calcium pectinate microspheres of curcumin for colon targeting.

PubMed

Zhang, Lin; Cao, Fengliang; Ding, Buyun; Li, Qilu; Xi, Yanwei; Zhai, Guangxi

2011-01-01

Currently, colon-specific drug delivery systems have been investigated for drugs that can exert their bioactivities in the colon. In this study, Eudragit® S100 coated calcium pectinate microsphere, a pH-dependent and enzyme-dependent system, as colon-specific delivery carrier for curcumin was investigated. Curcumin-loaded calcium pectinate microspheres were prepared by emulsification-linkage method, and the preparation technology was optimised by uniform experimental design. The morphology of microspheres was observed under scanning electron microscopy. Interactions between drug and polymers were investigated with differential scanning calorimetry (DSC) and X-ray diffraction. In vitro drug release studies were performed in simulated colonic fluid in the presence of Pectinex Ultra SP-L or 1% (w/v) rat caecal content, and the results indicated that the release of curcumin was significantly increased in the presence of 1% (w/v) rat caecal contents. It could be concluded that Eudragit® S100 coated calcium pectinate microsphere was a potential carrier for colon delivery of curcumin.

Study of a novel ultrasonically triggered drug vehicle with magnetic resonance properties.

PubMed

Liu, Tse-Ying; Huang, Hsin-Hui; Chen, Yen-Ju; Chen, Yu-Jen

2011-02-01

We developed a novel ultrasonically triggered drug vehicle with magnetic resonance (MR) properties by encapsulating superparamagnetic iron oxide (SPIO) nanoparticles in hydroxyapatite (HA)-coated liposomes. The effects of HA coating on the background leakage, ultrasound response and MR signal were investigated. HA coating of liposomes significantly reduced the background leakage of liposome. It also enhanced their sensitivity to ultrasound regardless of HA thickness or ultrasound frequency, even under sonication conditions of high frequency (1 and 3 MHz) and low power density (0.2-0.4 Wcm(-2)) used for diagnosis. However, it was found that the ultrasonically triggered vehicle could exhibit T(2) contrast in MR images by encapsulating SPIO. However, HA coating reduced the r(2) value of SPIO encapsulated in liposomes, but had no significant effect on the r(2)(∗) value, implying that MR images of HA-coated liposomes encapsulating SPIO could be probed by the T(2)(∗) signal. Most importantly, the r(2)(∗)-r(2) value of HA-coated liposomes encapsulating SPIO decreased after sonication, suggesting that the proposed vehicle could be used not only as a MR-guided drug vehicle capable of ultrasonically triggered release but also as a MR reporter to probe ultrasonic triggering. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Near-infrared light-responsive liposomal contrast agent for photoacoustic imaging and drug release applications.

PubMed

Sivasubramanian, Kathyayini; Mathiyazhakan, Malathi; Wiraja, Christian; Upputuri, Paul Kumar; Xu, Chenjie; Pramanik, Manojit

2017-04-01

Photoacoustic imaging has become an emerging tool for theranostic applications. Not only does it help in

Near-infrared light-responsive liposomal contrast agent for photoacoustic imaging and drug release applications

NASA Astrophysics Data System (ADS)

Sivasubramanian, Kathyayini; Mathiyazhakan, Malathi; Wiraja, Christian; Upputuri, Paul Kumar; Xu, Chenjie; Pramanik, Manojit

2017-04-01

Photoacoustic imaging has become an emerging tool for theranostic applications. Not only does it help in in vivo, noninvasive imaging of biological structures at depths but it can also be used for drug release and therapeutic applications. We explore near-infrared light-sensitive liposomes coated with gold nanostars (AuNSs) for both imaging and drug release applications using a photoacoustic imaging system. Being amphiphilic, the liposomes lipid bilayer and the aqueous core enable encapsulation of both hydrophobic and hydrophilic drugs. The AuNSs on the surface of the liposomes act as photon absorbers due to their intrinsic surface plasmon resonance. Upon excitation by laser light at specific wavelength, AuNSs facilitate rapid release of the contents encapsulated in the liposomes due to local heating and pressure wave formation (photoacoustic wave). Herein, we describe the design and optimization of the AuNSs-coated liposomes and demonstrate the release of both hydrophobic and hydrophilic model drugs (paclitaxel and calcein, respectively) through laser excitation at near-infrared wavelength. The use of AuNSs-coated liposomes as contrast agents for photoacoustic imaging is also explored with tissue phantom experiments. In comparison to blood, the AuNSs-coated liposomes have better contrast (approximately two times) at 2-cm imaging depth.

Hyaluronan polymer length, grafting density, and surface poly(ethylene glycol) coating influence in vivo circulation and tumor targeting of hyaluronan-grafted liposomes.

PubMed

Qhattal, Hussaini Syed Sha; Hye, Tanvirul; Alali, Amer; Liu, Xinli

2014-06-24

Hyaluronan-grafted liposomes (HA-liposomes) preferentially target CD44-overexpressing tumor cells in vitro via receptor-mediated endocytosis. We investigated the pharmacokinetics and biodistribution of HA-liposomes with various sizes of HA (MW 5-8, 50-60, and 175-350 kDa) in mice. Incorporation of negatively charged HA on the liposome surface compromised its blood circulation time, which led to decreased tumor accumulation in CD44+ human breast cancer MDA-MB-231 xenografts compared to PEGylated liposomes (PEG-5000). Clearance of HA-liposomes was HA polymer length-dependent; high MW (175-350 kDa, highest ligand binding affinity) HA-liposomes displayed faster clearance compared to low MW (5-8, 50-60 kDa) HA-liposomes or PEGylated liposomes. Surface HA ligand density can also affect clearance of HA-liposomes. Thus, HA is not an effective stealth coating material. When dual coating of PEG and HA was used, the PEG-HA-liposomes displayed similar blood circulation time and tumor accumulation to that of the PEGylated liposomes; however, the PEG-HA-liposomes displayed better cellular internalization capability in vivo. Tumor histology showed that PEG-HA-liposomes had a more direct association with CD44+ cancer cells, while PEGylated liposomes located predominantly in the tumor periphery, with less association with CD44+ cells. Flow cytometry analysis of ex vivo tumor cells showed that PEG-HA-liposomes had significantly higher tumor cell internalization compared to PEGylated liposomes. This study demonstrates that a long blood circulation time is critical for active tumor targeting. Furthermore, the use of the tumor-targeting ligand HA does not increase total tumor accumulation of actively targeted liposomes in solid tumors; however, it can enhance intracellular delivery.

Silica-coated flexible liposomes as a nanohybrid delivery system for enhanced oral bioavailability of curcumin

PubMed Central

Li, Chong; Zhang, Yan; Su, Tingting; Feng, Lianlian; Long, Yingying; Chen, Zhangbao

2012-01-01

We investigated flexible liposomes as a potential oral drug delivery system. However, enhanced membrane fluidity and structural deformability may necessitate liposomal surface modification when facing the harsh environment of the gastrointestinal tract. In the present study, silica-coated flexible liposomes loaded with curcumin (CUR-SLs) having poor water solubility as a model drug were prepared by a thin-film method with homogenization, followed by the formation of a silica shell by the sol-gel process. We systematically investigated the physical properties, drug release behavior, pharmacodynamics, and bioavailability of CUR-SLs. CUR-SLs had a mean diameter of 157 nm and a polydispersity index of 0.14, while the apparent entrapment efficiency was 90.62%. Compared with curcumin-loaded flexible liposomes (CUR-FLs) without silica-coatings, CUR-SLs had significantly higher stability against artificial gastric fluid and showed more sustained drug release in artificial intestinal fluid as determined by in vitro release assays. The bioavailability of CUR-SLs and CUR-FLs was 7.76- and 2.35-fold higher, respectively, than that of curcumin suspensions. Silica coating markedly improved the stability of flexible liposomes, and CUR-SLs exhibited a 3.31-fold increase in bioavailability compared with CUR-FLs, indicating that silica-coated flexible liposomes may be employed as a potential carrier to deliver drugs with poor water solubility via the oral route with improved bioavailability. PMID:23233804

Silica-coated flexible liposomes as a nanohybrid delivery system for enhanced oral bioavailability of curcumin.

PubMed

Li, Chong; Zhang, Yan; Su, Tingting; Feng, Lianlian; Long, Yingying; Chen, Zhangbao

2012-01-01

We investigated flexible liposomes as a potential oral drug delivery system. However, enhanced membrane fluidity and structural deformability may necessitate liposomal surface modification when facing the harsh environment of the gastrointestinal tract. In the present study, silica-coated flexible liposomes loaded with curcumin (CUR-SLs) having poor water solubility as a model drug were prepared by a thin-film method with homogenization, followed by the formation of a silica shell by the sol-gel process. We systematically investigated the physical properties, drug release behavior, pharmacodynamics, and bioavailability of CUR-SLs. CUR-SLs had a mean diameter of 157 nm and a polydispersity index of 0.14, while the apparent entrapment efficiency was 90.62%. Compared with curcumin-loaded flexible liposomes (CUR-FLs) without silica-coatings, CUR-SLs had significantly higher stability against artificial gastric fluid and showed more sustained drug release in artificial intestinal fluid as determined by in vitro release assays. The bioavailability of CUR-SLs and CUR-FLs was 7.76- and 2.35-fold higher, respectively, than that of curcumin suspensions. Silica coating markedly improved the stability of flexible liposomes, and CUR-SLs exhibited a 3.31-fold increase in bioavailability compared with CUR-FLs, indicating that silica-coated flexible liposomes may be employed as a potential carrier to deliver drugs with poor water solubility via the oral route with improved bioavailability.

HIGHLY METHYL ESTERIFIED SEEDS is a pectin methyl esterase involved in embryo development.

PubMed

Levesque-Tremblay, Gabriel; Müller, Kerstin; Mansfield, Shawn D; Haughn, George W

2015-03-01

Homogalacturonan pectin domains are synthesized in a highly methyl-esterified form that later can be differentially demethyl esterified by pectin methyl esterase (PME) to strengthen or loosen plant cell walls that contain pectin, including seed coat mucilage, a specialized secondary cell wall of seed coat epidermal cells. As a means to identify the active PMEs in seed coat mucilage, we identified seven PMEs expressed during seed coat development. One of these, HIGHLY METHYL ESTERIFIED SEEDS (HMS), is abundant during mucilage secretion, peaking at 7 d postanthesis in both the seed coat and the embryo. We have determined that this gene is required for normal levels of PME activity and homogalacturonan methyl esterification in the seed. The hms-1 mutant displays altered embryo morphology and mucilage extrusion, both of which are a consequence of defects in embryo development. A significant decrease in the size of cells in the embryo suggests that the changes in embryo morphology are a consequence of lack of cell expansion. Progeny from a cross between hms-1 and the previously characterized PME inhibitor5 overexpression line suggest that HMS acts independently from other cell wall-modifying enzymes in the embryo. We propose that HMS is required for cell wall loosening in the embryo to facilitate cell expansion during the accumulation of storage reserves and that its role in the seed coat is masked by redundancy. © 2015 American Society of Plant Biologists. All Rights Reserved.

Delivery of fluorophores by calcium phosphate-coated nanoliposomes and interaction with Staphylococcus aureus biofilms.

PubMed

Rivero Berti, Ignacio; Dell' Arciprete, María Laura; Dittler, María Laura; Miñan, Alejandro; Fernández Lorenzo de Mele, Mónica; Gonzalez, Mónica

2016-06-01

The delivery capacity and mechanical stability of calcium phosphate (CaP) coated 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) liposomes free and adsorbed on bacterial surface was investigated introducing either acridine orange (AO) or 5,10,15,20-Tetrakis(1-methyl-4-pyridinio)porphyrin (TMP) in the aqueous core of the liposomes. The obtained nanomaterials were thoroughly characterized by electron and optical microscopy and by fluorescence techniques. Distribution of the AO and TMP molecules between the aqueous liposomes core and the outer solution was demonstrated by the band shifts and broadening of the excitation-emission matrices and the modified Stern-Volmer model for fluorescence quenching. In aqueous suspensions, c.a. 40% of AO was released to the outer solution while only a small percentage of TMP was observed to reach the outer liposome surface. The nanoliposomes adhesion capacity and the leaking of fluorophore molecules to Staphylococcus aureus (S. aureus) biofilms were further evaluated. A close interaction between liposomes and S. aureus biofilm was evidenced by TEM and SEM imaging. Epifluorescence experiments demonstrated that CaP-coated liposomes have good biofilm staining capability after two hours incubation of the biofilms with the liposomes, thus supporting an important release of the fluorophores when in contact with the biofilm. Altogether, the obtained results strongly suggest that CaP-coated liposomes are capable of activating drug release when in presence of S. aureus biofilms and smears. The studies herein presented, indicate that CaP-coated liposomes are potential vehicles for the selective delivery of drugs to S. aureus biofilms, as is the case of the singlet oxygen photosensitizer TMP, a well known photodynamic antibacterial agent. Copyright © 2016 Elsevier B.V. All rights reserved.

Design and Development of Mixed Film of Pectin: Ethyl Cellulose for Colon Specific Drug Delivery of Sennosides and Triphala

PubMed Central

Momin, Munira; Pundarikakshudu, K.; Nagori, S. A.

2008-01-01

The present study was aimed at developing colon specific drug delivery system for sennosides and Triphala. These drugs are reputed Ayurvedic medicines for constipation in India. The proposed device explored the application of pectin and ethyl cellulose as a mixed film for colon specific delivery. This mixed film was prepared using non-aqueous solvents like acetone and isopropyl alcohol. A 32 factorial design was adopted to optimize the formulation variables like, ratio of ethyl cellulose to pectin (X1) and coat weight (X2). The rate and extent of drug release were found to be related to the thickness and the ratio of pectin to ethyl cellulose within the film. Statistical treatments to the drug release data revealed that the X1 variable was more important than X2. Under simulated colonic conditions, drug release was more pronounced from coating formulations containing higher proportions of pectin. The surface of the device was coated with Eudragit S100 to ensure that the device was more pH dependent and trigger the drug release only at higher pH. The final product is expected to have the advantage of being biodegradable and pH dependant. This type of a film effectively releases the drug while maintaining its integrity. PMID:20046742

Integration of antimicrobial pectin-based edible coating and active modified atmosphere packaging to preserve the quality and microbial safety of fresh-cut persimmon (Diospyros kaki Thunb. cv. Rojo Brillante).

PubMed

Sanchís, Elena; Ghidelli, Christian; Sheth, Chirag C; Mateos, Milagros; Palou, Lluís; Pérez-Gago, María B

2017-01-01

The greatest hurdle to the commercial marketing of fresh-cut fruits is related to their higher susceptibility to enzymatic browning, tissue softening, and microbial growth. The aim of this study was to test the efficacy of a pectin-based edible coating and low oxygen modified atmosphere packaging (MAP) to control enzymatic browning and reduce microbial growth of fresh-cut 'Rojo Brillante' persimmon. The survival of Escherichia coli, Salmonella enteritidis and Listeria monocytogenes artificially inoculated on fresh-cut fruit was also assessed. The pectin coating was amended with 500 IU mL -1 nisin (NI) as antimicrobial agent and 10 g kg -1 citric acid and 10 g kg -1 calcium chloride as anti-browning and firming agents, respectively. Persimmon slices were dipped in the coating or in water (control) and packed under 5 kPa O 2 (MAP) or in ambient atmosphere for up to 9 days at 5 °C. Microbial growth, package gas composition, colour, firmness, polyphenol oxidase activity, visual quality and overall sensory flavour of persimmon slices were measured during storage. Coating application combined with active MAP significantly reduced the CO 2 emission and O 2 consumption in the package. The coating was effective in reducing browning and also inhibited the growth of mesophilic aerobic bacteria. Coating also reduced the populations of E. coli, S. enteritidis and L. monocytogenes. The combination of the pectin-based edible coating and active MAP proved to be the most effective treatment to maintain the sensory and microbiological quality of persimmon slices for more than 9 days of storage. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Application of statistical experimental design to study the formulation variables influencing the coating process of lidocaine liposomes.

PubMed

González-Rodríguez, M L; Barros, L B; Palma, J; González-Rodríguez, P L; Rabasco, A M

2007-06-07

In this paper, we have used statistical experimental design to investigate the effect of several factors in coating process of lidocaine hydrochloride (LID) liposomes by a biodegradable polymer (chitosan, CH). These variables were the concentration of CH coating solution, the dripping rate of this solution on the liposome colloidal dispersion, the stirring rate, the time since the liposome production to the liposome coating and finally the amount of drug entrapped into liposomes. The selected response variables were drug encapsulation efficiency (EE, %), coating efficiency (CE, %) and zeta potential. Liposomes were obtained by thin-layer evaporation method. They were subsequently coated with CH according the experimental plan provided by a fractional factorial (2(5-1)) screening matrix. We have used spectroscopic methods to determine the zeta potential values. The EE (%) assay was carried out in dialysis bags and the brilliant red probe was used to determine CE (%) due to its property of forming molecular complexes with CH. The graphic analysis of the effects allowed the identification of the main formulation and technological factors by the analysis of the selected responses and permitted the determination of the proper level of these factors for the response improvement. Moreover, fractional design allowed quantifying the interactions between the factors, which will consider in next experiments. The results obtained pointed out that LID amount was the predominant factor that increased the drug entrapment capacity (EE). The CE (%) response was mainly affected by the concentration of the CH solution and the stirring rate, although all the interactions between the main factors have statistical significance.

Improved permeability of acyclovir: optimization of mucoadhesive liposomes using the phospholipid vesicle-based permeation assay.

PubMed

Naderkhani, Elenaz; Erber, Astrid; Škalko-Basnet, Nataša; Flaten, Gøril Eide

2014-02-01

The antiviral drug acyclovir (ACV) suffers from poor solubility both in lipophilic and hydrophilic environment, leading to low and highly variable bioavailability. To overcome these limitations, this study aimed at designing mucoadhesive ACV-containing liposomes to improve its permeability. Liposomes were prepared from egg phosphatidylcholine (E-PC) and E-PC/egg phosphatidylglycerol (E-PC/E-PG) and their surfaces coated with Carbopol. All liposomal formulations were fully characterized and for the first time the phospholipid vesicle-based permeation assay (PVPA) was used for testing in vitro permeability of drug from mucoadhesive liposome formulations. The negatively charged E-PC/E-PG liposomes could encapsulate more ACV than neutral E-PC liposomes. Coating with Carbopol increased the entrapment in the neutral E-PC liposomes. The incorporation of ACV into liposomes exhibited significant increase in its in vitro permeability, compared with its aqueous solution. The neutral E-PC liposomal formulations exhibited higher ACV permeability values compared with charged E-PC/E-PG formulations. Coating with Carbopol significantly enhanced the permeability from the E-PC/E-PG liposomes, as well as sonicated E-PC liposomes, which showed the highest permeability of all tested formulations. The increased permeability was according to the formulations' mucoadhesive properties. This indicates that the PVPA is suitable to distinguish between permeability of ACV from different mucoadhesive liposome formulations developed for various routes of administration. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Comparison of sorafenib-loaded poly (lactic/glycolic) acid and DPPC liposome nanoparticles in the in vitro treatment of renal cell carcinoma.

PubMed

Liu, James; Boonkaew, Benjawan; Arora, Jaspreet; Mandava, Sree Harsha; Maddox, Michael M; Chava, Srinivas; Callaghan, Cameron; He, Jibao; Dash, Srikanta; John, Vijay T; Lee, Benjamin R

2015-03-01

The objective of this study is to develop and compare several Sorafenib-loaded biocompatible nanoparticle models in order to optimize drug delivery and tumor cellular kill thereby improving the quality of Sorafenib-regimented chemotherapy. Sorafenib-loaded poly (lactic-co-glycolic) acid (PLGA), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, and hydrophobically modified chitosan (HMC)-coated DPPC liposomes were evaluated for several characteristics including zeta potential, drug loading, and release profile. Cytotoxicity and uptake trials were also studied using cell line RCC 786-0, a human metastatic clear cell histology renal cell carcinoma cell line. Sorafenib-loaded PLGA particles and HMC-coated DPPC liposomes exhibited significantly improved cell kill compared to Sorafenib alone at lower concentrations, namely 10-15 and 5-15 μM from 24 to 96 h, respectively. At maximum dosage and time (15 μM and 96 h), Sorafenib-loaded PLGA and HMC-coated liposomes killed 88.3 ± 1.8% and 98 ± 1.1% of all tumor cells, significant values compared with Sorafenib 81.8 ± 1.7% (p < 0.01). Likewise, HMC coating substantially improved cell kill for liposome model for all concentrations (5-15 μM) and at time points (24-96 h) (p < 0.01). PLGA and HMC-coated liposomes are promising platforms for drug delivery of Sorafenib. Because of different particle characteristics of PLGA and liposomes, each model can be further developed for unique clinical modalities. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Metronidazole loaded pectin microspheres for colon targeting.

PubMed

Vaidya, Ankur; Jain, Aviral; Khare, Piush; Agrawal, Ram K; Jain, Sanjay K

2009-11-01

A multiparticulate system having pH-sensitive property and specific enzyme biodegradability for colon-targeted delivery of metronidazole was developed. Pectin microspheres were prepared using emulsion-dehydration technique. These microspheres were coated with Eudragit(R) S-100 using oil-in-oil solvent evaporation method. The SEM was used to characterize the surface of these microspheres and a distinct coating over microspheres could be seen. The in vitro drug release studies exhibited no drug release at gastric pH, however continuous release of drug was observed from the formulation at colonic pH. Further, the release of drug from formulation was found to be higher in the presence of rat caecal contents, indicating the effect of colonic enzymes on the pectin microspheres. The in vivo studies were also performed by assessing the drug concentration in various parts of the GIT at different time intervals which exhibited the potentiality of formulation for colon targeting. Hence, it can be concluded that Eudragit coated pectin microspheres can be used for the colon specific delivery of drug. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

Pectin-based oral drug delivery to the colon.

PubMed

Sande, Sverre Arne

2005-05-01

This review presents an overview of studies concerning oral formulations intended for site-specific drug delivery to the colon with pectin as the main excipient. The biological aspects covered include gastrointestinal transit and the enzymatic degradation of pectin. Scintigraphic methods demonstrating the functionality of pectin formulations are discussed. The main focus is on the various formulations reported, including matrix tablets, multiparticulate formulations as pellets and hydrogel beads, and pectin-based coatings. Also included is an evaluation of common excipients employed to improve colon specificity by crosslinking or increasing the hydrophobicity. Finally, properties of the pectin molecules that are important for successful formulations are examined. The conclusion is that the studies found in the literature provide an excellent platform for the development of pectin-based colon delivery systems.

Fortification of dark chocolate with spray dried black mulberry (Morus nigra) waste extract encapsulated in chitosan-coated liposomes and bioaccessability studies.

PubMed

Gültekin-Özgüven, Mine; Karadağ, Ayşe; Duman, Şeyma; Özkal, Burak; Özçelik, Beraat

2016-06-15

Fine-disperse anionic liposomes containing black mulberry (Morus nigra) extract (BME) were prepared by high pressure homogenization at 25,000 psi. Primary liposomes were coated with cationic chitosan (0.4, w/v%) using the layer-by-layer depositing method and mixed with maltodextrin (MD) (20, w/v%) prior to spray drying. After that, spray dried liposomal powders containing BME were added to chocolates with alkalization degrees (pH 4.5, 6, 7.5) at conching temperatures of 40 °C, 60 °C, and 80 °C. The results showed that, compared to spray dried extract, chitosan coated liposomal powders provided better protection of anthocyanin content in both increased temperature and pH. In addition, encapsulation in liposomes enhanced in vitro bioaccessability of anthocyanins. Chocolate was fortified with encapsulated anthocyanins maximum 76.8% depending on conching temperature and pH. Copyright © 2016. Published by Elsevier Ltd.

Body distributioin of RGD-mediated liposome in brain-targeting drug delivery.

PubMed

Qin, Jing; Chen, DaWei; Hu, Haiyang; Qiao, MingXi; Zhao, XiuLi; Chen, Baoyu

2007-09-01

RGD conjugation liposomes (RGD-liposomes) were evaluated for brain-targeting drug delivery. The flow cytometric in vitro study demonstrated that RGD-liposomes could bind to monocytes and neutrophils effectively. Ferulic acid (4-hydroxy-3-methoxycinnamic, FA) was loaded into liposomes. Rats were subjected to intrastriatal microinjections of 100 units of human recombinant IL-1beta to produce brain inflammation and caudal vein injection of three formulations (FA solution, FA liposome and RGD-coated FA liposome). Animals were sacrificed 15, 30, 60 and 120 min after administration to study the body distribution of the FA in the three formulations. HPLC was used to determine the concentration of FA in vivo with salicylic acid as internal standard. The results of body distribution indicated that RGD-coated liposomes could be mediated into the brain with a 6-fold FA concentration compared to FA solution and 3-fold in comparison to uncoated liposome. Brain targeted delivery was achieved and a reduction in dosage might be allowed.

Direct measurements of interfacial interactions between pectin and kappa-casein and implications for the stabilisation of calcium-free casein micelle mimics.

PubMed

Cucheval, A; Al-Ghobashy, M A; Hemar, Y; Otter, D; Williams, M A K

2009-10-15

Using Surface Plasmon Resonance (SPR) it has been shown that the fine structure of the anionic polysaccharide pectin strongly influences its interfacial interaction with a kappa-casein layer coated onto a gold surface (via a dextran linker) in the pH range 3.5-6.8, with the highest SPR signal being observed for pectin with the lowest charge density tested (a degree of methylesterification (DM) around 90%). Furthermore, the Brownian motions of kappa-casein coated polystyrene beads (used to provide calcium-free 'model casein micelles') were studied in pectin solutions using Diffusing Wave Spectroscopy (DWS) and microscopy, and were compared with measurements made on naked beads. At every pH value studied (with the exception of 3.5), bridging of the protein-covered probe particles was observed for pectins of both DM 28 and DM 78. However, no aggregated complexes were found in these model casein micelle systems when pectin of an unusually high DM was used (90%). It was hypothesised that having a limited number of binding regions of spatially limited extent maximises the number of chains binding to the protein layer (as found with the SPR measurement), encourages the formation of loops and trains, and additionally limits the potential for destabilisation via bridging.

Nitric Oxide Releasing Coronary Stent: A New Approach Using Layer-by-Layer Coating and Liposomal Encapsulation.

PubMed

Elnaggar, Mahmoud A; Seo, Seong Ho; Gobaa, Samy; Lim, Kyung Seob; Bae, In-Ho; Jeong, Myung Ho; Han, Dong Keun; Joung, Yoon Ki

2016-11-01

The sustained or controlled release of nitric oxide (NO) can be the most promising approach for the suppression or prevention of restenosis and thrombosis caused by stent implantation. The aim of this study is to investigate the feasibility in the potential use of layer-by-layer (LBL) coating with a NO donor-containing liposomes to control the release rate of NO from a metallic stent. Microscopic observation and surface characterizations of LBL-modified stents demonstrate successful LBL coating with liposomes on a stent. Release profiles of NO show that the release rate is sustained up to 5 d. In vitro cell study demonstrates that NO release significantly enhances endothelial cell proliferation, whereas it markedly inhibits smooth muscle cell proliferation. Finally, in vivo study conducted with a porcine coronary injury model proves the therapeutic efficacy of the NO-releasing stents coated by liposomal LBL technique, supported by improved results in luminal healing, inflammation, and neointimal thickening except thrombo-resistant effect. As a result, all these results demonstrate that highly optimized release rate and therapeutic dose of NO can be achieved by LBL coating and liposomal encapsulation, followed by significantly efficacious outcome in vivo. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface coating of siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers: enhanced gene silencing and reduced adverse effects in vitro

NASA Astrophysics Data System (ADS)

Zeng, Xianghui; de Groot, Anne Marit; Sijts, Alice J. A. M.; Broere, Femke; Oude Blenke, Erik; Colombo, Stefano; van Eden, Willem; Franzyk, Henrik; Nielsen, Hanne Mørck; Foged, Camilla

2015-11-01

Cationic vectors have demonstrated the potential to facilitate intracellular delivery of therapeutic oligonucleotides. However, enhanced transfection efficiency is usually associated with adverse effects, which also proves to be a challenge for vectors based on cationic peptides. In this study a series of proteolytically stable palmitoylated α-peptide/β-peptoid peptidomimetics with a systematically varied number of repeating lysine and homoarginine residues was shown to self-assemble with small interfering RNA (siRNA). The resulting well-defined nanocomplexes were coated with anionic lipids giving rise to net anionic liposomes. These complexes and the corresponding liposomes were optimized towards efficient gene silencing and low adverse effects. The optimal anionic liposomes mediated a high silencing effect, which was comparable to that of the control (cationic Lipofectamine 2000), and did not display any noticeable cytotoxicity and immunogenicity in vitro. In contrast, the corresponding nanocomplexes mediated a reduced silencing effect with a more narrow safety window. The surface coating with anionic lipid bilayers led to partial decomplexation of the siRNA-peptidomimetic nanocomplex core of the liposomes, which facilitated siRNA release. Additionally, the optimal anionic liposomes showed efficient intracellular uptake and endosomal escape. Therefore, these findings suggest that a more efficacious and safe formulation can be achieved by surface coating of the siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers.Cationic vectors have demonstrated the potential to facilitate intracellular delivery of therapeutic oligonucleotides. However, enhanced transfection efficiency is usually associated with adverse effects, which also proves to be a challenge for vectors based on cationic peptides. In this study a series of proteolytically stable palmitoylated α-peptide/β-peptoid peptidomimetics with a systematically varied number of repeating lysine and homoarginine residues was shown to self-assemble with small interfering RNA (siRNA). The resulting well-defined nanocomplexes were coated with anionic lipids giving rise to net anionic liposomes. These complexes and the corresponding liposomes were optimized towards efficient gene silencing and low adverse effects. The optimal anionic liposomes mediated a high silencing effect, which was comparable to that of the control (cationic Lipofectamine 2000), and did not display any noticeable cytotoxicity and immunogenicity in vitro. In contrast, the corresponding nanocomplexes mediated a reduced silencing effect with a more narrow safety window. The surface coating with anionic lipid bilayers led to partial decomplexation of the siRNA-peptidomimetic nanocomplex core of the liposomes, which facilitated siRNA release. Additionally, the optimal anionic liposomes showed efficient intracellular uptake and endosomal escape. Therefore, these findings suggest that a more efficacious and safe formulation can be achieved by surface coating of the siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers. Electronic supplementary information (ESI) available: Non-fusogenic liposomes; cytotoxicity of naked siRNA and the empty vector; immunogenicity; low-magnification images; DOPE/DPPC liposomes. See DOI: 10.1039/c5nr04807a

Flying saucer1 is a transmembrane RING E3 ubiquitin ligase that regulates the degree of pectin methylesterification in Arabidopsis seed mucilage.

PubMed

Voiniciuc, Catalin; Dean, Gillian H; Griffiths, Jonathan S; Kirchsteiger, Kerstin; Hwang, Yeen Ting; Gillett, Alan; Dow, Graham; Western, Tamara L; Estelle, Mark; Haughn, George W

2013-03-01

Pectins are complex polysaccharides that form the gel matrix of the primary cell wall and are abundant in the middle lamella that holds plant cells together. Their degree of methylesterification (DM) impacts wall strength and cell adhesion since unesterified pectin regions can cross-link via Ca(2+) ions to form stronger gels. Here, we characterize flying saucer1 (fly1), a novel Arabidopsis thaliana seed coat mutant, which displays primary wall detachment, reduced mucilage extrusion, and increased mucilage adherence. These defects appear to result from a lower DM in mucilage and are enhanced by the addition of Ca(2+) or completely rescued using alkaline Ca(2+) chelators. FLY1 encodes a transmembrane protein with a RING-H2 domain that has in vitro E3 ubiquitin ligase activity. FLY1 is orthologous to TRANSMEMBRANE UBIQUITIN LIGASE1, a Golgi-localized E3 ligase involved in the quality control of membrane proteins in yeast. However, FLY1-yellow fluorescent protein (YFP) fusions are localized in punctae that are predominantly distinct from the Golgi and the trans-Golgi network/early endosome in the seed coat epidermis. Wortmannin treatment, which induces the fusion of late endosomes in plants, resulted in enlarged FLY1-YFP bodies. We propose that FLY1 regulates the DM of pectin in mucilage, potentially by recycling pectin methylesterase enzymes in the endomembrane system of seed coat epidermal cells.

FLYING SAUCER1 Is a Transmembrane RING E3 Ubiquitin Ligase That Regulates the Degree of Pectin Methylesterification in Arabidopsis Seed Mucilage[W

PubMed Central

Voiniciuc, Cătălin; Dean, Gillian H.; Griffiths, Jonathan S.; Kirchsteiger, Kerstin; Hwang, Yeen Ting; Gillett, Alan; Dow, Graham; Western, Tamara L.; Estelle, Mark; Haughn, George W.

2013-01-01

Pectins are complex polysaccharides that form the gel matrix of the primary cell wall and are abundant in the middle lamella that holds plant cells together. Their degree of methylesterification (DM) impacts wall strength and cell adhesion since unesterified pectin regions can cross-link via Ca2+ ions to form stronger gels. Here, we characterize flying saucer1 (fly1), a novel Arabidopsis thaliana seed coat mutant, which displays primary wall detachment, reduced mucilage extrusion, and increased mucilage adherence. These defects appear to result from a lower DM in mucilage and are enhanced by the addition of Ca2+ or completely rescued using alkaline Ca2+ chelators. FLY1 encodes a transmembrane protein with a RING-H2 domain that has in vitro E3 ubiquitin ligase activity. FLY1 is orthologous to TRANSMEMBRANE UBIQUITIN LIGASE1, a Golgi-localized E3 ligase involved in the quality control of membrane proteins in yeast. However, FLY1–yellow fluorescent protein (YFP) fusions are localized in punctae that are predominantly distinct from the Golgi and the trans-Golgi network/early endosome in the seed coat epidermis. Wortmannin treatment, which induces the fusion of late endosomes in plants, resulted in enlarged FLY1-YFP bodies. We propose that FLY1 regulates the DM of pectin in mucilage, potentially by recycling pectin methylesterase enzymes in the endomembrane system of seed coat epidermal cells. PMID:23482858

Alendronate-coated long-circulating liposomes containing 99mtechnetium-ceftizoxime used to identify osteomyelitis

PubMed Central

Ferreira, Diego dos Santos; Boratto, Fernanda Alves; Cardoso, Valbert Nascimento; Serakides, Rogéria; Fernandes, Simone Odília; Ferreira, Lucas Antônio Miranda; Oliveira, Mônica Cristina

2015-01-01

Osteomyelitis is a progressive destruction of bones caused by microorganisms. Inadequate or absent treatment increases the risk of bone growth inhibition, fractures, and sepsis. Among the diagnostic techniques, functional images are the most sensitive in detecting osteomyelitis in its early stages. However, these techniques do not have adequate specificity. By contrast, radiolabeled antibiotics could improve selectivity, since they are specifically recognized by the bacteria. The incorporation of these radiopharmaceuticals in drug-delivery systems with high affinity for bones could improve the overall uptake. In this work, long-circulating and alendronate-coated liposomes containing 99mtechnetium-radiolabeled ceftizoxime were prepared and their ability to identify infectious foci (osteomyelitis) in animal models was evaluated. The effect of the presence of PEGylated lipids and surface-attached alendronate was evaluated. The bone-targeted long-circulating liposomal 99mtechnetium–ceftizoxime showed higher uptake in regions of septic inflammation than did the non-long-circulating and/or alendronate-non-coated liposomes, showing that both the presence of PEGylated lipids and alendronate coating are important to optimize the bone targeting. Scintigraphic images of septic or aseptic inflammation-bearing Wistar rats, as well as healthy rats, were acquired at different time intervals after the intravenous administration of these liposomes. The target-to-non-target ratio proved to be significantly higher in the osteomyelitis-bearing animals for all investigated time intervals. Biodistribution studies were also performed after the intravenous administration of the formulation in osteomyelitis-bearing animals. A significant amount of liposomes were taken up by the organs of the mononuclear phagocyte system (liver and spleen). Intense renal excretion was also observed during the entire experiment period. Moreover, the liposome uptake by the infectious focus was significantly high. These results show that long-circulating and alendronate-coated liposomes containing 99mtechnetium-radiolabeled ceftizoxime have a tropism for infectious foci. PMID:25848262

Redox-responsive microbeads containing thiolated pectin-doxorubicin conjugate inhibit tumor growth and metastasis: An in vitro and in vivo study.

PubMed

Cheewatanakornkool, Kamonrak; Niratisai, Sathit; Dass, Crispin R; Sriamornsak, Pornsak

2018-07-10

The objective of this study was to investigate the in vitro cytotoxicity and in vivo anticancer efficacy of redox-responsive microbeads containing thiolated pectin-doxorubicin (DOX) conjugate. Oral microbeads were coated with an enteric polymer to protect the drug from release in the upper gastrointestinal (GI) tract and allow redox-triggered drug release in the colon. Morphology, particle size, drug content, and in vitro drug release behavior of the microbeads were characterized; in vitro cytotoxicity was tested on mouse colon carcinoma, human colorectal adenocarcinoma, and human bone osteosarcoma cell lines. In vivo anticancer efficacy of coated microbeads was examined in BALB/c mice with murine colon carcinoma. These coated microbeads significantly inhibited the growth of all cell lines. The in vivo study confirmed delivery of DOX to the colorectal tumor site, redox-responsiveness, and anticancer efficacy of coated microbeads. Coated microbeads also effectively inhibited primary tumor growth and suppressed tumor metastases without gross toxicity to the non-target tissue. No noticeable damage was found in mouse GI tissues, indicating lack of DOX toxicity. These novel coated microbeads containing thiolated pectin-DOX conjugate may be a promising vehicle for targeted clinical delivery of DOX to the colorectal cancer site by oral administration. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

'One-component' ultrathin multilayer films based on poly(vinyl alcohol) as stabilizing coating for phenytoin-loaded liposomes.

PubMed

Zasada, Katarzyna; Łukasiewicz-Atanasov, Magdalena; Kłysik, Katarzyna; Lewandowska-Łańcucka, Joanna; Gzyl-Malcher, Barbara; Puciul-Malinowska, Agnieszka; Karewicz, Anna; Nowakowska, Maria

2015-11-01

Ultrathin "one-component" multilayer polymeric films for potential biomedical applications were designed based on polyvinyl alcohol,-a non-toxic, fully degradable synthetic polymer. Good uniformity of the obtained film and adequate adsorption properties of the polymeric layers were achieved by functional modification of the polymer, which involved synthesis of cationic and anionic derivatives. Synthesized polymers were characterized by FTIR, NMR spectroscopy, dynamic light scattering measurements and elemental analysis. The layer by layer assembly technique was used to build up a multilayer film and this process was followed using UV-Vis spectroscopy and ellipsometry. The morphology and thickness of the obtained multilayered film material was evaluated by atomic force microscopy (AFM). Preliminary studies on the application of the obtained multilayer film for coating of liposomal nanocarriers containing phenytoin, an antiarrhythmic drug, were performed. The coating effectively stabilizes liposomes and the effect increases with an increasing number of deposited layers until the polymeric film reaches the optimal thickness. The obtained release profiles suggest that bilayer-coated liposomes release phenytoin less rapidly than uncoated ones. The cytotoxicity studies performed for all obtained nanocarriers confirmed that none of them has negative effect on cell viability. All of the performed experiments suggest that liposomes coated with ultrathin film obtained from PVA derivatives can be attractive drug nanocarriers. Copyright © 2015 Elsevier B.V. All rights reserved.

Accelerated healing of skin burns by anti-Gal/alpha-gal liposomes interaction.

PubMed

Galili, Uri; Wigglesworth, Kim; Abdel-Motal, Ussama M

2010-03-01

Topical application of alpha-gal liposomes on burns results in rapid local recruitment of neutrophils and macrophages. Recruited macrophages are pivotal for healing of burns because they secrete cytokines/growth factors that induce epidermis regeneration and tissue repair. alpha-Gal liposomes have glycolipids with alpha-gal epitopes (Galalpha1-3Galbeta1-4GlcNAc-R) which bind anti-Gal, the most abundant natural antibody in humans constituting approximately 1% of immunoglobulins. Interaction of alpha-gal liposomes with anti-Gal within the fluid film formed on burns, activates complement and generates chemotactic complement cleavage peptides which effectively recruit neutrophils and macrophages. Anti-Gal IgG coating alpha-gal liposomes further binds to Fcgamma receptors on macrophages and activates them to secrete cytokines/growth factors. Efficacy of alpha-gal liposomes treatment in accelerating burn healing is demonstrated in the experimental model of alpha1,3galactosyltransferase knockout mice. These mice are the only available nonprimate mammals that can produce anti-Gal in titers similar to those in humans. Pairs of burns in mice were covered either with a spot bandage coated with 10mg alpha-gal liposomes, or with a control spot bandage coated with saline. On Day 3 post-treatment, the alpha-gal liposomes treated burns contained approximately 5-fold as many neutrophils as control burns, whereas macrophages were found only in alpha-gal liposomes treated burns. On Day 6, 50-100% of the surface area of alpha-gal liposomes treated burns were covered with regenerating epidermis (re-epithelialization), whereas almost no epidermis was found in control burns. The extensive recruitment of macrophages by anti-Gal/alpha-gal liposomes interaction was further demonstrated in vivo with polyvinyl alcohol (PVA) sponge discs containing alpha-gal liposomes, implanted subcutaneously. Since anti-Gal is abundant in all humans, it is suggested that treatment with alpha-gal liposomes will be effective also in patients with burns and other skin wounds. Copyright (c) 2009 Elsevier Ltd and ISBI. All rights reserved.

Nanocapsule of cationic liposomes obtained using "in situ" acrylic acid polymerization: stability, surface charge and biocompatibility.

PubMed

Scarioti, Giovana Danieli; Lubambo, Adriana; Feitosa, Judith P A; Sierakowski, Maria Rita; Bresolin, Tania M B; de Freitas, Rilton Alves

2011-10-15

In this work, didecyldimethylammonium bromide (DDAB) and 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) (2.5:1) were used to prepare liposomes coated with polyacrylic acid (PAA) using "in situ" polymerization with 2.5, 5 and 25 mM of acrylic acid (AA). The PAA concentrations were chosen to achieve partially to fully covered capsules, and the polymerization reaction was observed with real-time monitoring using dynamic light scattering (NanoDLS). The DDAB:DOPE liposomes showed stability in the tested temperature range (25-70°C), whereas the results confirmed the success of the polymerization according to superficial charge (zeta potential of +66.7±1.2 mV) results and AFM images. For the liposomes that were fully coated with PAA (zeta potential of +0.3±3.9 mV), cytotoxicity was independent of the concentration of albumin. Cationic liposomes and nanocapsules of the stable liposomes coated with PAA were obtained by controlling the surface charge, which was the most important factor related to cytotoxicity. Thus, a potential, safe drug nanocarrier was successfully developed in this work. Copyright © 2011 Elsevier B.V. All rights reserved.

Surface properties of semi-synthetic enteric coating films: Opportunities to develop bio-based enteric coating films for colon- targeted delivery

USDA-ARS?s Scientific Manuscript database

This study investigated the surface properties of the semi-synthetic enteric coating materials for potential colon- targeted bioactive delivery. The enteric coating materials were produced by combining nanoscale resistant starch, pectin, and carboxymethylcellulose. The surface properties of the co...

Optimization, in vitro release and bioavailability of gamma-oryzanol-loaded calcium pectinate microparticles reinforced with chitosan.

PubMed

Kim, Jong Soo; Lee, Ji-Soo; Chang, Pahn-Shick; Lee, Hyeon Gyu

2010-09-30

Response surface methodology was used to optimize coating conditions, including chitosan concentration (X(1)) and coating time (X(2)), for sustained release of chitosan-coated Ca-pectinate (CP) microparticles containing oryzanol (OZ). The optimized values of X(1) and X(2) were found to be 1.48% and 69.92 min, respectively. These optimized values agreed favorably with the predicted results, indicating the utility of predictive models for the release of OZ in simulated intestinal fluid. In vitro release studies revealed that the chitosan-coated CP microparticles were quite stable under acidic conditions, but swell and disintegrate under alkaline conditions. In vivo release study of OZ, physically entrapped within chitosan-coated CP microcapsules, demonstrated the sustained release of OZ and could be used to improve the bioavailability of OZ following oral administration. Copyright 2010 Elsevier B.V. All rights reserved.

Lipogels: surface-adherent composite hydrogels assembled from poly(vinyl alcohol) and liposomes

NASA Astrophysics Data System (ADS)

Jensen, Bettina E. B.; Hosta-Rigau, Leticia; Spycher, Philipp R.; Reimhult, Erik; Städler, Brigitte; Zelikin, Alexander N.

2013-07-01

Drug-eluting engineered surface coatings are of paramount importance for many biomedical applications from implantable devices to tissue engineering. Herein, we present the assembly of lipogels, composite physical hydrogels assembled from poly(vinyl alcohol) and liposomes using thiol-disulfide exchange between end group modified PVA and thiocholesterol containing liposomes, and the response of adhering cells to these coatings. We demonstrate the controlled loading of liposomes into the polymer matrix and the preserved mechanical properties of the lipogels. Furthermore, the lipogels are successfully rendered cell adhesive by incorporation of poly(l-lysine) into the PVA polymer matrix or by poly(dopamine) coating of the lipogels. The successful lipid uptake from the lipogels by macrophages, hepatocytes, and myoblasts was monitored by flow cytometry. Finally, the delivery of active cargo, paclitaxel, to adherent myoblasts is shown, thus illustrating the potential of the lipogels as a drug eluting interface for biomedical applications.Drug-eluting engineered surface coatings are of paramount importance for many biomedical applications from implantable devices to tissue engineering. Herein, we present the assembly of lipogels, composite physical hydrogels assembled from poly(vinyl alcohol) and liposomes using thiol-disulfide exchange between end group modified PVA and thiocholesterol containing liposomes, and the response of adhering cells to these coatings. We demonstrate the controlled loading of liposomes into the polymer matrix and the preserved mechanical properties of the lipogels. Furthermore, the lipogels are successfully rendered cell adhesive by incorporation of poly(l-lysine) into the PVA polymer matrix or by poly(dopamine) coating of the lipogels. The successful lipid uptake from the lipogels by macrophages, hepatocytes, and myoblasts was monitored by flow cytometry. Finally, the delivery of active cargo, paclitaxel, to adherent myoblasts is shown, thus illustrating the potential of the lipogels as a drug eluting interface for biomedical applications. Electronic supplementary information (ESI) available: Paclitaxel calibration curve and images of DIC of PLL blended PVA physical hydrogels, lipogel FRAP, and different cell lines attached to lipogels are available. See DOI: 10.1039/c3nr01662e

Effect of modified pectin molecules on the growth of bone cells.

PubMed

Kokkonen, Hanna E; Ilvesaro, Joanna M; Morra, Marco; Schols, Henk A; Tuukkanen, Juha

2007-02-01

The aim of this study was to investigate molecular candidates for bone implant nanocoatings, which could improve biocompatibility of implant materials. Primary rat bone cells and murine preosteoblastic MC3T3-E1 cells were cultured on enzymatically modified hairy regions (MHR-A and MHR-B) of apple pectins. MHRs were covalently attached to tissue culture polystyrene (TCPS) or glass. Uncoated substrata or bone slices were used as controls. Cell attachment, proliferation, and differentiation were investigated with fluorescence and confocal microscopy. Bone cells seem to prefer MHR-B coating to MHR-A coating. On MHR-A samples, the overall numbers as well as proportions of active osteoclasts were diminished compared to those on MHR-B, TCPS, or bone. Focal adhesions indicating attachment of the osteoblastic cells were detected on MHR-B and uncoated controls but not on MHR-A. These results demonstrate the possibility to modify surfaces with pectin nanocoatings.

Interaction of S-layer proteins of Lactobacillus kefir with model membranes and cells.

PubMed

Hollmann, Axel; Delfederico, Lucrecia; Santos, Nuno C; Disalvo, E Anibal; Semorile, Liliana

2018-06-01

In previous works, it was shown that S-layer proteins from Lactobacillus kefir were able to recrystallize and stabilize liposomes, this feature reveling a great potential for developing liposomal-based carriers. Despite previous studies on this subject are important milestones, a number of questions remain unanswered. In this context, the feasibility of S-layer proteins as a biomaterial for drug delivery was evaluated in this work. First, S-layer proteins were fully characterized by electron microscopy, 2D-electrophoresis, and anionic exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). Afterward, interactions of S-layer proteins with model lipid membranes were evaluated, showing that proteins adsorb to the lipid surface following a non-fickean or anomalous diffusion, when positively charged lipid were employed, suggesting that electrostatic interaction is a key factor in the recrystallization process on these proteins. Finally, the interaction of S-layer coated liposomes with Caco-2 cell line was assessed: First, cytotoxicity of formulations was tested showing no cytotoxic effects in S-layer coated vesicles. Second, by flow cytometry, it was observed an increased ability to transfer cargo molecules into Caco-2 cells from S-layer coated liposomes in comparison to control ones. All data put together, supports the idea that a combination of adhesive properties of S-layer proteins concomitant with higher stability of S-layer coated liposomes represents an exciting starting point in the development of new drug carriers.

Bioreactor droplets from liposome-stabilized all-aqueous emulsions

NASA Astrophysics Data System (ADS)

Dewey, Daniel C.; Strulson, Christopher A.; Cacace, David N.; Bevilacqua, Philip C.; Keating, Christine D.

2014-08-01

Artificial bioreactors are desirable for in vitro biochemical studies and as protocells. A key challenge is maintaining a favourable internal environment while allowing substrate entry and product departure. We show that semipermeable, size-controlled bioreactors with aqueous, macromolecularly crowded interiors can be assembled by liposome stabilization of an all-aqueous emulsion. Dextran-rich aqueous droplets are dispersed in a continuous polyethylene glycol (PEG)-rich aqueous phase, with coalescence inhibited by adsorbed ~130-nm diameter liposomes. Fluorescence recovery after photobleaching and dynamic light scattering data indicate that the liposomes, which are PEGylated and negatively charged, remain intact at the interface for extended time. Inter-droplet repulsion provides electrostatic stabilization of the emulsion, with droplet coalescence prevented even for submonolayer interfacial coatings. RNA and DNA can enter and exit aqueous droplets by diffusion, with final concentrations dictated by partitioning. The capacity to serve as microscale bioreactors is established by demonstrating a ribozyme cleavage reaction within the liposome-coated droplets.

Bioreactor droplets from liposome-stabilized all-aqueous emulsions.

PubMed

Dewey, Daniel C; Strulson, Christopher A; Cacace, David N; Bevilacqua, Philip C; Keating, Christine D

2014-08-20

Artificial bioreactors are desirable for in vitro biochemical studies and as protocells. A key challenge is maintaining a favourable internal environment while allowing substrate entry and product departure. We show that semipermeable, size-controlled bioreactors with aqueous, macromolecularly crowded interiors can be assembled by liposome stabilization of an all-aqueous emulsion. Dextran-rich aqueous droplets are dispersed in a continuous polyethylene glycol (PEG)-rich aqueous phase, with coalescence inhibited by adsorbed ~130-nm diameter liposomes. Fluorescence recovery after photobleaching and dynamic light scattering data indicate that the liposomes, which are PEGylated and negatively charged, remain intact at the interface for extended time. Inter-droplet repulsion provides electrostatic stabilization of the emulsion, with droplet coalescence prevented even for submonolayer interfacial coatings. RNA and DNA can enter and exit aqueous droplets by diffusion, with final concentrations dictated by partitioning. The capacity to serve as microscale bioreactors is established by demonstrating a ribozyme cleavage reaction within the liposome-coated droplets.

Melittin liposomes surface modified with poloxamer 188: in vitro characterization and in vivo evaluation.

PubMed

Tian, J L; Ke, X; Chen, Z; Wang, C J; Zhang, Y; Zhong, T C

2011-05-01

Melittin liposomes surface modified with poloxamer 188 were developed, and the effect of poloxamer 188 was investigated with regard to anti-cancer effect and vascular stimulation. Melittin liposomes surface modified with poloxamer 188 at different concentrations (0%, 2%, and 5%) were prepared using the adsorption method, followed by in vitro characterization, including entrapment efficiency, zeta potential, particle size, and morphology. Subsequently, the influence of repeated freeze-thawing on the liposomes was investigated, and the effect of poloxamer 188 on the repeated freeze-thawing process was explored. Vascular stimulation effects of MLT, and MLT liposome that surface coated with or without poloxamer were all studied. Pharmacokinetics of the different MLT preparations were determined and the anticancer activity of the MLT formulations was investigated. The particle size of the liposomes gradually increased with increasing poloxamer 188 content, while the entrapment efficiency did not change significantly. After the first freeze-thaw cycle, size and PDI were both markedly reduced, entrapment efficiency rose, and there was no significant change of zeta potential. The vascular irritation caused by MLT could be reduced to an extent by encapsulation in liposome, but not completely eliminated, while liposomes coated with poloxamer 188 can effectively abolish the phenomenon. Melittin liposomes with surface modified by poloxamer exhibit enhanced bioavailability, effective anticancer activity, and reduced side effects compared with melittin solution. Poloxamer plays an important role in melittin liposomes.

Focal Activation of Cells by Plasmon Resonance Assisted Optical Injection of Signaling Molecules

PubMed Central

2015-01-01

Experimental methods for single cell intracellular delivery are essential for probing cell signaling dynamics within complex cellular networks, such as those making up the tumor microenvironment. Here, we show a quantitative and general method of interrogation of signaling pathways. We applied highly focused near-infrared laser light to optically inject gold-coated liposomes encapsulating bioactive molecules into single cells for focal activation of cell signaling. For this demonstration, we encapsulated either inositol trisphosphate (IP3), an endogenous cell signaling second messenger, or adenophostin A (AdA), a potent analogue of IP, within 100 nm gold-coated liposomes, and injected these gold-coated liposomes and their contents into the cytosol of single ovarian carcinoma cells to initiate calcium (Ca2+) release from intracellular stores. Upon optical injection of IP3 or AdA at doses above the activation threshold, we observed increases in cytosolic Ca2+ concentration within the injected cell initiating the propagation of a Ca2+ wave throughout nearby cells. As confirmed by octanol-induced inhibition, the intercellular Ca2+ wave traveled via gap junctions. Optical injection of gold-coated liposomes represents a quantitative method of focal activation of signaling cascades of broad interest in biomedical research. PMID:24877558

Pectin from Citrus Canning Wastewater as Potential Fat Replacer in Ice Cream.

PubMed

Zhang, Hua; Chen, Jianle; Li, Junhui; Wei, Chaoyang; Ye, Xingqian; Shi, John; Chen, Shiguo

2018-04-17

Pectin had been recovered from canning wastewater produced by chemical treatment of segment membrane during preparation of canned citrus in our previous research. The purpose of this study was to characterize the extracted pectin from canning wastewater, and to evaluate its application as a fat alternative to replace fat in ice cream. The monosaccharide composition and rheological properties of the pectin were determined. The influences of fat reduction and pectin addition on the physicochemical, rheological and sensory properties of low-fat ice cream were determined. The rheological results showed that pectin solutions were typical pseudoplastic fluids. The addition of pectin in ice cream can cause an increase in viscosity, overrun, and hardness, and a decrease in meltdown of the ice cream. When 0.72% pectin ( w / w ) is incorporated into ice cream, a prototype product of ice cream with 45% lower fat content compared to the control was made. Results indicated that their qualities such as appearance, flavor, and taste were not significantly different. The low-fat ice cream had higher smoothness scores and lower mouth-coating scores. Hence, pectin extracted from citrus canning wastewater can be potentially used as fat replacer in ice cream, which benefits both the environment and the food industry.

Sensing specific adhesion of liposomal and micellar systems with attached carbohydrate recognition structures at lectin surfaces.

PubMed

Hildebrand, Annegret; Schaedlich, Anita; Rothe, Ulrich; Neubert, Reinhard H H

2002-05-15

A quartz crystal microbalance was used to investigate the adsorption behavior of liposomes and mixed micelles with attached carbohydrate recognition structures at lectin-coated quartz plates. With a self-assembly technique, the quartz was coated with the lectin Concanavalin A. In a first attempt, liposomes of natural soybean PC as well as synthetic POPC, containing 10% reactive N-Glut-PE each, were decorated with a mannopyranoside recognition structure to investigate the specific adsorption at the lectin-coated quartz surface in dependence on the concentration. In a second model, the bile salt sodium cholate was introduced to solubilize the mannopyranoside-modified liposomes and to transform them into mannopyranoside-modified binary mixed micelles. The adsorption of these micelles was further investigated. In a third approach, the adsorption behavior of mannopyranoside-modified ternary mixed bile salt-phosphatidylcholine-fatty acid micelles was characterized with sodium laurate, palmitate, and oleate as fatty acids. The micelles with oleate showed only a small frequency decrease, whereas the micelles with laurate and palmitate induced higher frequency changes. A dependence on the alkyl chain length could be detected. While the adsorption of liposomes containing recognition structures at QCM surfaces is nowadays well-established, the QCM detection of the adsorption of mixed bile salt micelles, transformed from these liposomes by solubilization, is a novel and very promising field for the development of innovative colloidal drug delivery systems.

Zein/caseinate/pectin complex nanoparticles: Formation and characterization.

PubMed

Chang, Chao; Wang, Taoran; Hu, Qiaobin; Luo, Yangchao

2017-11-01

In this study, pectin was used as coating material to form zein/caseinate/pectin complex nanoparticles through pH adjustment and heating treatment for potential oral delivery applications. The preparation conditions were studied by applying heating treatment at different pHs, either the isoelectric point of zein (pH 6.2) or caseinate (pH 4.6), or consecutively at both pHs. The particulate characteristics, including particle size, polydispersity index, and zeta potential were monitored for complex nanoparticles formed under different preparation conditions. The complex nanoparticles generally exhibited particle size smaller than 200nm with narrow distribution, spherical shape, and strong negative charge. Fourier transform infrared and fluorescence spectroscopy revealed that hydrophobic interactions and hydrogen bonds were involved in the formation of complex nanoparticles, in addition to electrostatic interactions. Fresh colloidal dispersion and freeze-dried powders varied in their morphology, depending on their preparation conditions. Our results suggested that heating pH and sequence significantly affected the morphology of complex nanoparticles, and pectin coating exerted stabilization effect under simulated gastrointestinal conditions. The present study provides insight into the formation of protein/polysaccharide complex nanoparticles under different preparation conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Liposome-based mucus-penetrating particles (MPP) for mucosal theranostics: demonstration of diamagnetic chemical exchange saturation transfer (diaCEST) magnetic resonance imaging (MRI).

PubMed

Yu, Tao; Chan, Kannie W Y; Anonuevo, Abraham; Song, Xiaolei; Schuster, Benjamin S; Chattopadhyay, Sumon; Xu, Qingguo; Oskolkov, Nikita; Patel, Himatkumar; Ensign, Laura M; van Zjil, Peter C M; McMahon, Michael T; Hanes, Justin

2015-02-01

Mucus barriers lining mucosal epithelia reduce the effectiveness of nanocarrier-based mucosal drug delivery and imaging ("theranostics"). Here, we describe liposome-based mucus-penetrating particles (MPP) capable of loading hydrophilic agents, e.g., the diaCEST MRI contrast agent barbituric acid (BA). We observed that polyethylene glycol (PEG)-coated liposomes containing ≥7 mol% PEG diffused only ~10-fold slower in human cervicovaginal mucus (CVM) compared to their theoretical speeds in water. 7 mol%-PEG liposomes contained sufficient BA loading for diaCEST contrast, and provided improved vaginal distribution compared to 0 and 3mol%-PEG liposomes. However, increasing PEG content to ~12 mol% compromised BA loading and vaginal distribution, suggesting that PEG content must be optimized to maintain drug loading and stability. Non-invasive diaCEST MRI illustrated uniform vaginal coverage and longer retention of BA-loaded 7 mol%-PEG liposomes compared to unencapsulated BA. Liposomal MPP with optimized PEG content hold promise for drug delivery and imaging at mucosal surfaces. This team of authors characterized liposome-based mucus-penetrating particles (MPP) capable of loading hydrophilic agents, such as barbituric acid (a diaCEST MRI contrast agent) and concluded that liposomal MPP with optimized PEG coating enables drug delivery and imaging at mucosal surfaces. Copyright © 2015 Elsevier Inc. All rights reserved.

Impact of atomization technique on the stability and transport efficiency of nebulized liposomes harboring different surface characteristics.

PubMed

Lehofer, Bernhard; Bloder, Florian; Jain, Pritesh P; Marsh, Leigh M; Leitinger, Gerd; Olschewski, Horst; Leber, Regina; Olschewski, Andrea; Prassl, Ruth

2014-11-01

The objective of this study was to evaluate the impact of nebulization on liposomes with specific surface characteristics by applying three commercially available inhaler systems (air-jet, ultrasonic and vibrating-mesh). Conventional liposome formulations composed of phosphatidylcholine and cholesterol were compared to sterically stabilized PEGylated liposomes and cationic polymer coated liposomes.Liposomes of similar size (between 140 and 165 nm in diameter with polydispersity indices <0.1) were prepared by dry lipid film rehydration followed by size extrusion. Their stability upon nebulization was determined in terms of size, polydispersity index and leakage using a fluorescence quenching system. The transport efficiencies of the nebulizer devices and the influences of both salt and liposomes on the droplet size distribution of the aerosol were investigated. While the droplet size of the aerosol decreased with increasing salt concentration the liposomes had no influence on the droplet size distribution. The output of the nebulizers in terms of liposomal transport efficiencies differed significantly among the nebulizer principles (20–100%, p < 0.05), with the vibrating-mesh nebulizers being the most effective. The integrity of the conventional liposomes was almost unaffected by the atomization process, while polymer coated and especially positively charged liposomes showed enhanced leakage. The release rates for the hydrophilic model drug system were highest for the vibrating-mesh nebulizers regardless of the surface characteristics of the liposomes (increasing from 10% to 20% and 50% for the conventional, PEGylated and positively charged formulations, respectively). In view of surface modified liposomes our data suggest that drug delivery via nebulization necessitates the finding of a compromise between nebulizer efficiency, formulation stability and drug release profile to accomplish the development of tailored formulations suitable for advanced inhalation therapy.

Preparation and evaluation of a chitosan-coated antioxidant liposome containing vitamin C and folic acid.

PubMed

Jiao, Zhen; Wang, Xiudong; Yin, Yuting; Xia, Jingxin; Mei, Yanan

2018-05-03

Vitamin C (VC) and folic acid (FA) are the important nutrient and antioxidant in human body. In order to improve their stability, their co-loaded liposomes (VCFA-Lip) and chitosan-coated liposomes (CS-VCFA-Lip) are prepared and characterised. The mean particle size of VCFA-Lip and CS-VCFA-Lip is 138 nm and 249 nm, respectively. The encapsulation efficiencies of both drugs for CS-VCFA-Lip are much higher than those for VCFA-Lip. Furthermore, the experimental results show that the antioxidant activity of CS-VCFA-Lip is higher than that of VCFA-Lip. Moreover, the storage stability study reveals that the chitosan coating can efficiently improve the physical stability of VCFA-Lip. These results indicate that stability of VC and FA can be greatly improved after being wrapped by liposomes. In addition, the performance of CS-VCFA-Lip is better than VCFA-Lip, indicating CS-VCFA-Lip can be applied as a promising delivery system for the antioxidant defence system to the food industry and cosmetic industry.

Composite films from pectin and fish skin gelatin or soybean flour protein.

PubMed

Liu, LinShu; Liu, Cheng-Kung; Fishman, Marshall L; Hicks, Kevin B

2007-03-21

Composite films were prepared from pectin and fish skin gelatin (FSG) or pectin and soybean flour protein (SFP). The inclusion of protein promoted molecular interactions, resulting in a well-organized homogeneous structure, as revealed by scanning electron microscopy and fracture-acoustic emission analysis. The resultant composite films showed an increase in stiffness and strength and a decrease in water solubility and water vapor transmission rate, in comparison with films cast from pectin alone. The composite films inherited the elastic nature of proteins, thus being more flexible than the pure pectin films. Treating the composite films with glutaraldehyde/methanol induced chemical cross-linking with the proteins and reduced the interstitial spaces among the macromolecules and, consequently, improved their mechanical properties and water resistance. Treating the protein-free pectin films with glutaraldehyde/methanol also improved the Young's modulus and tensile strength, but showed little effect on the water resistance, because the treatment caused only dehydration of the pectin films and the dehydration is reversible. The composite films were biodegradable and possessed moderate mechanical properties and a low water vapor transmission rate. Therefore, the films are considered to have potential applications as packaging or coating materials for food or drug industries.

Evaluation of polyethylene glycol coated liposomes labeled with Tc-99m as a blood pool agent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, W.T.; Klipper, R.; Goins, B.

1994-05-01

This investigation evaluated Tc-99m liposomes coated with polyethylene glycol (PEG) as a blood pool agent in comparison with Tc-99m liposomes carrying no surface charge (Neutral) and with Tc-99m autologous red cells. Liposomes (135 nm diameter) encapsulating glutathione were labeled with Tc-99m using the lipophilic chelator, HMPAO as previously described. Autologous red cells were labeled using an Ultratag kit. Labeling efficiencies averaged 66%, 52%, and 97% for the PEG liposomes. Neutral liposomes, and red cells, respectively. Rabbits (3-3.5 Kg) were injected IV via ear vein with 2.0 mls of PEG liposomes (2 mCi, 17 mg phospholipid/Kg body weight, n=5). Neutral liposomesmore » (1.3 mCi, 17 mg phospholipid/Kg body weight, n=4), or red cells (2.6 mCi, n=2). Gamma camera images were acquired at 5,22, and 45 minutes, and 2,20,and 44 hours post-injection. Blood samples were obtained at each time point to determine clearance kinetics. Circulation half lives of both Tc-99m liposome formulations were longer than Tc-99m red cells (8 hrs), with the half life of PEG liposomes (35 hrs) 1.6 times longer than Neutral liposomes (22 hrs). In vivo stability of the Tc-99m label was excellent for the liposomes with only 3.5-4% bladder activity at 45 minutes compared to 12% bladder activity for the red cells. Excellent blood pool images were obtained for the PEG liposomes in the rabbit. Heart/liver ratios calculated from region of interest analysis of 45 minutes images were 1.9, 1.5, and 1.7 for PEG liposomes, Neutral liposomes and red cells. This study demonstrates the feasibility of using Tc-99m PEG liposomes to perform gated cardiac blood pool and rapid gastrointestinal bleeding studies.« less

Recent Advances and Perspectives in Liposomes for Cutaneous Drug Delivery.

PubMed

Carita, Amanda C; Eloy, Josimar O; Chorilli, Marlus; Lee, Robert J; Leonardi, Gislaine Ricci

2018-02-13

The cutaneous route is attractive for the delivery of drugs in the treatment of a wide variety of diseases. However the stratum corneum (SC) is an effective barrier that hampers skin penetration. Within this context, liposomes emerge as a potential carrier for improving topical delivery of therapeutic agents. In this review, we aimed to discuss key aspects for the topical delivery by drug-loaded liposomes. Phospholipid type and phase transition temperature have been shown to affect liposomal topical delivery. The effect of surface charge is subject to considerable variation depending on drug and composition. In addition, modified vesicles with the presence of components for permeation enhancement, such as surfactants and solvents, have been shown to have a considerable effect. These liposomes include: Transfersomes, Niosomes, Ethosomes, Transethosomes, Invasomes, coated liposomes, penetration enhancer containing vesicles (PEVs), fatty acids vesicles, Archaeosomes and Marinosomes. Furthermore, adding polymeric coating onto liposome surface could influence cutaneous delivery. Mechanisms of delivery include intact vesicular skin penetration, free drug diffusion, permeation enhancement, vesicle adsorption to and/or fusion with the SC, trans-appendageal penetration, among others. Finally, several skin conditions, including acne, melasma, skin aging, fungal infections and skin cancer, have benefited from liposomal topical delivery of drugs, with promising in vitro and in vivo results. However, despite the existence of some clinical trials, more studies are needed to be conducted in order to explore the potential of liposomes in the dermatological field. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Paclitaxel-loaded folate-coated long circulating and pH-sensitive liposomes as a potential drug delivery system: A biodistribution study.

PubMed

Monteiro, Liziane O F; Fernandes, Renata S; Oda, Caroline M R; Lopes, Sávia C; Townsend, Danyelle M; Cardoso, Valbert N; Oliveira, Mônica C; Leite, Elaine A; Rubello, Domenico; de Barros, André L B

2018-01-01

A range of antitumor agents for cancer treatment is available; however, they show low specificity, which often limit their use. Recently, we have reported the preparation of folate-coated long-circulating and pH-sensitive liposomes (SpHL-folate-PTX) loaded with paclitaxel (PTX), an effective drug for the treatment of solid tumors, including breast cancer. The purpose of this study was to prepare and characterize SpHL-PTX and SpHL-folate-PTX radiolabeled with technetium-99m ( 99m Tc). Biodistribution studies and scintigraphic images were performed after intravenous administration of 99m Tc-PTX, 99m Tc-SpHL-PTX and 99m Tc-SpHL-folate-PTX into healthy and tumor-bearing mice. High radiochemical purity (>98%) and in vitro stability (>90%) were achieved for both liposome formulations. The pharmacokinetic properties of 99m Tc-SpHL-DTPA-PTX and 99m Tc-SpHL-folate-DTPA-PTX decreased in a monophasic manner showing half-life of 400.1 and 541.8min, respectively. Scintigraphic images and biodistribution studies showed a significant uptake in liver, spleen and kidneys, demonstrating these routes as way for excretion. At 8h post-injection, the liposomal tumor uptake was higher than 99m Tc-PTX. Interesting, 4h after administration, the liposome folate coated showed higher tumor-to-muscle ratio than 99m Tc-SpHL-DTPA-PTX and 99m Tc-PTX. In conclusion, the liposomal systems, showed high tumor uptake by scintigraphic images, especially the 99m Tc-SpHL-folate-DTPA-PTX that showed a sustained and higher tumor-to-muscle ratio than non-functionalized liposome, which indicate its feasibility as a PTX delivery system to folate positive tumors. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effect of pectin charge density on formation of multilayer films with chitosan.

PubMed

Kamburova, Kamelia; Milkova, Viktoria; Petkanchin, Ivana; Radeva, Tsetska

2008-04-01

The effect of pectin charge density on the formation of multilayer films with chitosan (PEC/CHI) is studied by means of electro-optics. Pectins of low (21%) and high (71%) degrees of esterification, which are inversely proportional to the pectin charge density, are used to form films on colloidal beta-FeOOH particles at pH 4.0 when the CHI is fully ionized. We find that, after deposition of the first 3-4 layers, the film thickness increases linearly with the number of adsorbed layers. However, the increase in the film thickness is larger when the film is terminated with CHI. Irregular increase of the film thickness is more marked for the PEC with higher density of charge. Oscillation in the electrical polarizability of the film-coated particles with the number of deposited layers is also registered in the PEC/CHI films. The charge balance of the multilayers, calculated from electrical polarizability of the film-coated particles, is positive, with larger excess of positive charge within the film constructed from CHI and less charged PEC. This is attributed to the ability of CHI to diffuse into the film at each deposition step. Despite the CHI diffusion, the film thickness increases linearly due to the dissolution of unstable PEC/CHI complexes from the film surface.

Pharmacokinetic study of the structural components of adenosine diphosphate-encapsulated liposomes coated with fibrinogen γ-chain dodecapeptide as a synthetic platelet substitute.

PubMed

Taguchi, Kazuaki; Ujihira, Hayato; Ogaki, Shigeru; Watanabe, Hiroshi; Fujiyama, Atsushi; Doi, Mami; Okamura, Yosuke; Takeoka, Shinji; Ikeda, Yasuo; Handa, Makoto; Otagiri, Masaki; Maruyama, Toru

2013-08-01

Fibrinogen γ-chain (dodecapeptide HHLGGAKQAGDV, H12)-coated, ADP-encapsulated liposomes [H12-(ADP)-liposomes] were developed as a synthetic platelet alternative that specifically accumulates at bleeding sites as the result of interactions with activated platelets via glycoprotein IIb/IIIa and augments platelet aggregation by releasing ADP. The aim of this study is to characterize the pharmacokinetic properties of H12-(ADP)-liposomes and structural components in rats, and to predict the blood retention of H12-(ADP)-liposomes in humans. With use of H12-(ADP)-liposomes in which the encapsulated ADP and liposomal membrane cholesterol were radiolabeled with (14)C and (3)H, respectively, it was found that the time courses for the plasma concentration curves of (14)C and (3)H radioactivity showed that the H12-(ADP)-liposomes remained intact in the blood circulation for up to 24 hours after injection, and were mainly distributed to the liver and spleen. However, the (14)C and (3)H radioactivity of H12-(ADP)-liposomes disappeared from organs within 7 days after injection. The encapsulated ADP was metabolized to allantoin, which is the final metabolite of ADP in rodents, and was mainly eliminated in the urine, whereas the cholesterol was mainly eliminated in feces. In addition, the half-life of the H12-(ADP)-liposomes in humans was predicted to be approximately 96 hours from pharmacokinetic data obtained for mice, rats, and rabbits using an allometric equation. These results suggest that the H12-(ADP)-liposome has potential with proper pharmacokinetic and acceptable biodegradable properties as a synthetic platelet substitute.

Hyaluronan–cisplatin conjugate nanoparticles embedded in Eudragit S100-coated pectin/alginate microbeads for colon drug delivery

PubMed Central

Tsai, Shiao-Wen; Yu, Ding-Syuan; Tsao, Shu-Wei; Hsu, Fu-Yin

2013-01-01

Hyaluronan–cisplatin conjugate nanoparticles (HCNPs) were chosen as colon-targeting drug-delivery carriers due to the observation that a variety of malignant tumors overexpress hyaluronan receptors. HCNPs were prepared by mixing cisplatin with a hyaluronan solution, followed by dialysis to remove trace elements. The cells treated with HCNPs showed significantly lower viability than those treated with cisplatin alone. HCNPs were entrapped in Eudragit S100-coated pectinate/alginate microbeads (PAMs) by using an electrospray method and a polyelectrolyte multilayer-coating technique in aqueous solution. The release profile of HCNPs from Eudragit S100-coated HCNP-PAMs was pH-dependent. The percentage of 24-hour drug release was approximately 25.1% and 39.7% in pH 1.2 and pH 4.5 media, respectively. However, the percentage of drug released quickly rose to 75.6% at pH 7.4. Moreover, the result of an in vivo nephrotoxicity study demonstrated that Eudragit S100-coated HCNP-PAMs treatment could mitigate the nephrotoxicity that resulted from cisplatin. From these results, it can be concluded that Eudragit S100-coated HCNP-PAMs are promising carriers for colonspecific drug delivery. PMID:23861585

Development of Active Films From Pectin and Fruit Extracts: Light Protection, Antioxidant Capacity, and Compounds Stability.

PubMed

Eça, Kaliana S; Machado, Mariana T C; Hubinger, Miriam D; Menegalli, Florencia C

2015-11-01

Pectin films containing fruit extracts were developed and tested in relation to ultraviolet light transmission, phytochemical contents, and antioxidant capacity during 90 d shelf life storage. Aqueous and alcoholic extracts from 5 different fruits (acerola, cashew apple, papaya, pequi, and strawberry) were obtained. Because the alcoholic extracts from acerola, cashew apple, and strawberry presented the highest phytochemical content and antioxidant capacity, they were incorporated into pectin films individually or as a mixture. Incorporation of these extracts into pectin films provided antioxidant capacity while retaining the physical properties. The pectin films containing fruit extract acted as adequate light barrier and prevented photooxidation. Among the prepared films, the pectin film containing acerola extract afforded the highest antioxidant capacity, with a half-life of 99 d. Overall, the results revealed that incorporation of fruit extracts into pectin films potentially produces antioxidant films and coatings for different food applications. The production of pectin films incorporated with fruit extract is based on combination of the antioxidant activity, natural color, and optical barrier properties from fruit phytochemical components to the active film. This film could be potentially used as active packing on food products in order to protect their nutrients against free radicals action and photooxidation and, hence, preserve the quality, integrity, and safety of food during the storage period. © 2015 Institute of Food Technologists®

The potential use of novel chitosan-coated deformable liposomes in an ocular drug delivery system.

PubMed

Chen, Hongdan; Pan, Hao; Li, Panpan; Wang, Hui; Wang, Xin; Pan, Weisan; Yuan, Yue

2016-07-01

In this study, novel chitosan-coated deformable liposomes (DL-CS) were proposed as an ocular drug delivery system to prolong pre-corneal retention, and improve transcorneal penetration and absorption. Flurbiprofen-loaded deformable liposomes (FP-DL) were prepared by a modified ethanol injection method and then coated with chitosan. Both DL and DL-CS exhibited a homogeneous particle size distribution, high encapsulation efficiency and good stability. After coating with 0.1% CS, the zeta potential was shifted from negative to positive. The apparent permeability coefficient of FP-DL-0.1% CS evaluated using isolated rabbit corneas was 1.29-, 1.95- and 4.59- fold greater than that of uncoated FP-DL, conventional liposomes and FP solution (P<0.01), respectively. The in vivo pre-corneal retention time and elimination dynamics were assessed using gamma scintigraphy technology. The area under the remaining activity-time of FP-DL-0.1% CS was prolonged 2.84- and 1.53-fold compared with that of the FP solution and FP-DL groups, respectively. Moreover, the ocular irritation test in vivo revealed that DL-0.1% CS produced no ocular damage or abnormal clinical signs. These results indicate that DL-CS appears to be a novel ophthalmic drug delivery strategy with the potential to overcome the limitations of conventional eye drops. Copyright © 2016 Elsevier B.V. All rights reserved.

Liposome-coated mesoporous silica nanoparticles loaded with L-cysteine for photoelectrochemical immunoassay of aflatoxin B1.

PubMed

Lin, Youxiu; Zhou, Qian; Zeng, Yongyi; Tang, Dianping

2018-06-02

The authors describe a photoelectrochemical (PEC) immunoassay for determination of aflatoxin B 1 (AFB 1 ) in foodstuff. The competitive immunoreaction is carried out on a microplate coated with a capture antibody against AFB 1 using AFB 1 -bovine serum albumin (BSA)-liposome-coated mesoporous silica nanoparticles (MSN) loaded with L-cysteine as a support. The photocurrent is produced by a photoactive material consisting of cerium-doped Bi 2 MoO 6 . Initially, L-cysteine acting as the electron donor is gated in the pores by interaction between mesoporous silica and liposome. Thereafter, AFB 1 -BSA conjugates are covalently bound to the liposomes. Upon introduction of the analyte (AFB 1 ), the labeled AFB 1 -BSA complex competes with the analyte for the antibody deposited on the microplate. Accompanying with the immunocomplex, the liposomes on the MSNs are lysed upon addition of Triton X-100. This results in the opening of the pores and in a release of L-cysteine. Free cysteine then induces the electron-hole scavenger of the photoactive nanosheets to increase the photocurrent. The photocurrent (relative to background signal) increases with increasing AFB 1 concentration. Under optimum conditions, the photoactive nanosheets display good photoelectrochemical responses, and allow the detection of AFB 1 at a concentration as low as 0.1 pg·mL -1 within a linear response in the 0.3 pg·mL -1 to 10 ng·mL -1 concentration range. Accuracy was evaluated by analyzing naturally contaminated and spiked peanut samples by using a commercial AFB 1 ELISA kit as the reference, and well-matching results were obtained. Graphical abstract Schematic presentation of a photoelectrochemical immunoassay for AFB 1 . It is based on the use of Ce-doped Bi 2 MoO 6 nanosheets and of liposome-coated mesoporous silica nanoparticles loaded with L-cysteine.

Improvement in physicochemical parameters of DPPC liposomes and increase in skin permeation of aciclovir and minoxidil by the addition of cationic polymers.

PubMed

Hasanovic, Amra; Hollick, Caroline; Fischinger, Kerstin; Valenta, Claudia

2010-06-01

1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes were prepared by high-pressure homogeniser and coated with two cationic polymers, chitosan (CS) and for the first time Eudragit EPO (EU), respectively. Compared to the control liposomes, the polymeric liposomes showed greater physicochemical stability in terms of mean particle size and zeta potential at room temperature. In the present study, aciclovir and minoxidil have been used as hydrophilic and hydrophobic candidates. In the presence of the drugs, the polymeric liposomes still showed constant particle size and zeta potential. Influences of polymers and model drugs on thermotropic phase transition of DPPC liposomes were studied by micro-differential scanning calorimetry (microDSC). The influences on configuration of DPPC liposomes were investigated by Fourier transform infrared spectroscopy (FTIR). According to DSC results, cationic polymers had a stabilising effect, whereas aciclovir and minoxidil changed the physical properties of the DPPC bilayers by influencing the main phase transition temperature and erasing the pre-transition. The investigation of CO stretching bands of DPPC at 1736 cm(-1) in FTIR spectra showed that aciclovir has strong hydrogen bonding with CO groups of DPPC, whereas carbonyl groups were free in minoxidil presence. Moreover, the coating of liposomes with CS or EU led to higher skin diffusion for both drugs. This could be explained as an effect of positively charged liposomes to interact stronger with skin negatively charged surface and their possible interactions with structures below the stratum corneum. Copyright 2010 Elsevier B.V. All rights reserved.

Multifunctional gold coated thermo-sensitive liposomes for multimodal imaging and photo-thermal therapy of breast cancer cells

NASA Astrophysics Data System (ADS)

Rengan, Aravind Kumar; Jagtap, Madhura; de, Abhijit; Banerjee, Rinti; Srivastava, Rohit

2013-12-01

Plasmon resonant gold nanoparticles of various sizes and shapes have been extensively researched for their applications in imaging, drug delivery and photothermal therapy (PTT). However, their ability to degrade after performing the required function is essential for their application in healthcare. When combined with biodegradable liposomes, they appear to have better degradation capabilities. They degrade into smaller particles of around 5 nm that are eligible candidates for renal clearance. Distearoyl phosphatidyl choline : cholesterol (DSPC : CHOL, 8 : 2 wt%) liposomes have been synthesized and coated with gold by in situ reduction of chloro-auric acid. These particles of size 150-200 nm are analyzed for their stability, degradation capacity, model drug-release profile, biocompatibility and photothermal effects on cancer cells. It is observed that when these particles are subjected to low power continuous wave near infra-red (NIR) laser for more than 10 min, they degrade into small gold nanoparticles of size 5 nm. Also, the gold coated liposomes appear to have excellent biocompatibility and high efficiency to kill cancer cells through photothermal transduction. These novel materials are also useful in imaging using specific NIR dyes, thus exhibiting multifunctional properties for theranostics of cancer.Plasmon resonant gold nanoparticles of various sizes and shapes have been extensively researched for their applications in imaging, drug delivery and photothermal therapy (PTT). However, their ability to degrade after performing the required function is essential for their application in healthcare. When combined with biodegradable liposomes, they appear to have better degradation capabilities. They degrade into smaller particles of around 5 nm that are eligible candidates for renal clearance. Distearoyl phosphatidyl choline : cholesterol (DSPC : CHOL, 8 : 2 wt%) liposomes have been synthesized and coated with gold by in situ reduction of chloro-auric acid. These particles of size 150-200 nm are analyzed for their stability, degradation capacity, model drug-release profile, biocompatibility and photothermal effects on cancer cells. It is observed that when these particles are subjected to low power continuous wave near infra-red (NIR) laser for more than 10 min, they degrade into small gold nanoparticles of size 5 nm. Also, the gold coated liposomes appear to have excellent biocompatibility and high efficiency to kill cancer cells through photothermal transduction. These novel materials are also useful in imaging using specific NIR dyes, thus exhibiting multifunctional properties for theranostics of cancer. Electronic supplementary information (ESI) available: Additional figures. See DOI: 10.1039/c3nr04448c

Glycosaminoglycan-resistant and pH-sensitive lipid-coated DNA complexes produced by detergent removal method.

PubMed

Lehtinen, Julia; Hyvönen, Zanna; Subrizi, Astrid; Bunjes, Heike; Urtti, Arto

2008-10-21

Cationic polymers are efficient gene delivery vectors in in vitro conditions, but these carriers can fail in vivo due to interactions with extracellular polyanions, i.e. glycosaminoglycans (GAG). The aim of this study was to develop a stable gene delivery vector that is activated at the acidic endosomal pH. Cationic DNA/PEI complexes were coated by 1,2-dioleylphosphatidylethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS) (3:2 mol/mol) using two coating methods: detergent removal and mixing with liposomes prepared by ethanol injection. Only detergent removal produced lipid-coated DNA complexes that were stable against GAGs, but were membrane active at low pH towards endosome mimicking liposomes. In relation to the low cellular uptake of the coated complexes, their transfection efficacy was relatively high. PEGylation of the coated complexes increased their cellular uptake but reduced the pH-sensitivity. Detergent removal was thus a superior method for the production of stable, but acid activatable, lipid-coated DNA complexes.

Antibacterial activity of contact lenses bearing surface-immobilized layers of intact liposomes loaded with levofloxacin.

PubMed

Danion, Anne; Arsenault, Isabelle; Vermette, Patrick

2007-09-01

In vitro methods to evaluate antibacterial activity were used with contact lenses bearing levofloxacin-loaded liposomes developed for the prevention and treatment of bacterial ocular infections such as keratitis. Levofloxacin was incorporated into liposomes before these intact liposomes were immobilized onto the surfaces of soft contact lenses using a multilayer immobilization strategy. The release of levofloxacin from contact lenses bearing 2, 5, and 10 layers of liposomes into a saline buffer at 37 degrees C was monitored by fluorescence. The levofloxacin release, as a function of time, was described by a mechanism taking into account two independent first-order kinetic models. The total release of levofloxacin from the contact lenses was completed within 6 days. The release of levofloxacin from contact lenses bearing 10 layers of liposomes and subsequently soaked overnight in a levofloxacin solution was also studied and compare to that of dried contact lenses without any chemical modification rehydrated in a levofloxacin solution. The antibacterial activity of the liposome-coated contact lenses against Staphylococcus aureus was evaluated by measuring (i) the diameters of the inhibition zone on an agar plate and (ii) the optical density using a broth assay. The liposome-coated lenses showed an antibacterial activity both on agar and in broth following 24 h. When initial bacteria inocula were equal or below 10(6) CFU/mL, all the bacteria were inhibited within 2 h. When using initial bacteria inocula of 10(8) CFU/mL, an initial burst release provided by soaking the liposomal lenses was required for the first hours to inhibit bacteria growth. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

Size-dependent extravasation and interstitial localization of polyethyleneglycol liposomes in solid tumor-bearing mice.

PubMed

Ishida, O; Maruyama, K; Sasaki, K; Iwatsuru, M

1999-11-10

We have examined the size dependence of extravasation and interstitial localization of polyethyleneglycol-coated liposomes (PEG-liposomes) in the solid tumor tissue by means of electron microscopic observation. Liposomes composed of distearoyl phosphatidylcholine, cholesterol and distearoylphosphatidylethanolamine derivative of polyethyleneglycol (PEG) were prepared in various size ranges. PEG-liposomes with an average diameter of 100-200 nm showed the most prolonged circulation time and the greatest tumor accumulation in all the solid tumors employed in this experiment. Although large PEG-liposomes with a diameter of 400 nm showed a short circulation time in normal mice, the results in splenectomized mice indicated that they do have an intrinsic prolonged circulation character in vivo. However, large PEG-liposomes could not extravasate into solid tumor tissue. These results indicate that the size of liposomes is critical for extravasation. The electron microscopic observations revealed the almost exclusive engulfment of extravasated liposomes by tumor-associated macrophages; very few were taken up by tumor cells.

Ag@4ATP-coated liposomes: SERS traceable delivery vehicles for living cells.

PubMed

Zhu, Dan; Wang, Zhuyuan; Zong, Shenfei; Chen, Hui; Wu, Xin; Pei, Yuwei; Chen, Peng; Ma, Xueqin; Cui, Yiping

2014-07-21

A liposome-Ag nanohybrid has been demonstrated as a SERS traceable intracellular drug nanocarrier. Liposomes have been introduced for their special qualities in drug delivery systems. In essence, 4-aminothiophenol (4ATP) tagged Ag nanoparticles (Ag@4ATP) were adsorbed onto the surfaces of liposomes via electrostatic interactions, in which 4ATP was used as a SERS reporter. In such a nanohybrid, the locations of the carrier can be tracked by SERS signals while those of the drugs can be monitored through their fluorescence, allowing the simultaneous investigation of the intracellular distribution of both the carriers and the drugs. Our experimental results suggest that the reported liposomal system has substantial potential for intracellular drug delivery.

pHLIP®-Mediated Delivery of PEGylated Liposomes to Cancer Cells

PubMed Central

Yao, Lan; Daniels, Jennifer; Wijesinghe, Dayanjali; Andreev, Oleg A.; Reshetnyak, Yana K.

2013-01-01

We develop a method for pH-dependent fusion between liposomes and cellular membranes using pHLIP® (pH Low Insertion Peptide), which inserts into lipid bilayer of membrane only at low pH. Previously we establish the molecular mechanism of peptide action and show that pHLIP can target acidic diseased tissue. Here we investigate how coating of PEGylated liposomes with pHLIP might affect liposomal uptake by cells. The presence of pHLIP on the surface of PEGylated-liposomes enhanced membrane fusion and lipid exchange in a pH dependent fashion, leading to increase of cellular uptake and payload release, and inhibition of cell proliferation by liposomes containing ceramide. A novel type of pH-sensitive, “fusogenic” pHLIP-liposomes was developed, which could be used to selectively deliver various diagnostic and therapeutic agents to acidic diseased cells. PMID:23416366

Preparation, characterization, and in vitro release study of albendazole-encapsulated nanosize liposomes

PubMed Central

Panwar, Preety; Pandey, Bhumika; Lakhera, P C; Singh, K P

2010-01-01

The purpose of the present study was to formulate effective and controlled release albendazole liposomal formulations. Albendazole, a hydrophobic drug used for the treatment of hydatid cysts, was encapsulated in nanosize liposomes. Rapid evaporation method was used for the preparation of albendazole-encapsulated conventional and PEGylated liposomes consisting of egg phosphatidylcholine (PC) and cholesterol (CH) in the molar ratios of (6:4) and PC:CH: polyethylene glycol (PEG) (5:4:1), respectively. In this study, PEGylated and conventional liposomes containing albendazole were prepared and their characteristics, such as particle size, encapsulation efficiency, and in vitro drug release were investigated. The drug encapsulation efficiency of PEGylated and conventional liposomes was 81% and 72%, respectively. The biophysical characterization of both conventional and PEG-coated liposomes were done by transmission electron microscopy and UV-vis spectrophotometry. Efforts were made to study in vitro release of albendazole. The drug release rate showed decrease in albendazole release in descending order: free albendazole, albendazole-loaded conventional liposomes, and least with albendazole-loaded PEG-liposomes. Biologically relevant vesicles were prepared and in vitro release of liposome-entrapped albendazole was determined. PMID:20309396

A liposomal hydrogel for the prevention of bacterial adhesion to catheters.

PubMed

DiTizio, V; Ferguson, G W; Mittelman, M W; Khoury, A E; Bruce, A W; DiCosmo, F

1998-10-01

The adhesion of bacteria to medical implants and the subsequent development of a biofilm frequently results in the infection of surrounding tissue and may require removal of the device. We have developed a liposomal hydrogel system that significantly reduces bacterial adhesion to silicone catheter material. The system consists of a poly (ethylene glycol)-gelatin hydrogel in which liposomes containing the antibiotic ciprofloxacin are sequestered. A poly (ethylene glycol)-gelatin-liposome mixture was applied to a silicone surface that had been pre-treated with phenylazido-modified gelatin. Hydrogel cross-linking and attachment to surface-immobilized gelatin was accomplished through the formation of urethane bonds between gelatin and nitrophenyl carbonate-activated poly (ethylene glycol). Liposomal hydrogel-coated catheters were shown to have an initial ciprofloxacin content of 185+/-16 microg cm(-2). Ciprofloxacin was released over seven days with an average release rate of 1.9+/-0.2 microg cm(-2) h(-1) for the first 94 h. In vitro assays using a clinical isolate of Pseudomonas aeruginosa established the antimicrobial efficacy of the liposomal hydrogel. A modified Kirby-Bauer assay produced growth-inhibition zone diameters of 39+/-1 mm, while bacterial adhesion was completely inhibited on catheter surfaces throughout a seven-day in vitro adhesion assay. This new antimicrobial coating shows promise as a prophylactic and/or treatment for catheter-related infection.

The effect of polymer backbone chemistry on the induction of the accelerated blood clearance in polymer modified liposomes.

PubMed

Kierstead, Paul H; Okochi, Hideaki; Venditto, Vincent J; Chuong, Tracy C; Kivimae, Saul; Fréchet, Jean M J; Szoka, Francis C

2015-09-10

A variety of water-soluble polymers, when attached to a liposome, substantially increase liposome circulation half-life in animals. However, in certain conditions, liposomes modified with the most widely used polymer, polyethylene glycol (PEG), induce an IgM response resulting in an accelerated blood clearance (ABC) of the liposome upon the second injection. Modification of liposomes with other water-soluble polymers: HPMA (poly[N-(2-hydroxypropyl) methacrylamide]), PVP (poly(vinylpyrrolidone)), PMOX (poly(2-methyl-2-oxazoline)), PDMA (poly(N,N-dimethyl acrylamide)), and PAcM (poly(N-acryloyl morpholine)), increases circulation times of liposomes; but a precise comparison of their ability to promote long circulation or induce the ABC effect has not been reported. To obtain a more nuanced understanding of the role of polymer structure/MW to promote long circulation, we synthesized a library of polymer diacyl chain lipids with low polydispersity (1.04-1.09), similar polymer molecular weights (2.1-2.5kDa) and incorporated them into 100nm liposomes of a narrow polydispersity (0.25-1.3) composed of polymer-lipid/hydrogenated soy phosphatidylcholine/cholesterol/diD: 5.0/54.5/40/0.5. We confirm that HPMA, PVP, PMOX, PDMA and PAcM modified liposome have increased circulation times in rodents and that PVP, PDMA, and PAcM do not induce the ABC effect. We demonstrate for the first time, that HPMA does not cause an ABC effect whereas PMOX induces a pronounced ABC effect in rats. We find that a single dose of liposomes coated with PEG and PMOX generates an IgM response in rats towards the respective polymer. Finally, in this homologous polymer series, we observe a positive correlation (R=0.84 in rats, R=0.92 in mice) between the circulation time of polymer-modified liposomes and polymer viscosity; PEG and PMOX, the polymers that can initiate an ABC response were the two most viscous polymers. Our findings suggest that polymers that do not cause an ABC effect such as, HPMA or PVP, deserve further consideration as polymer coatings to improve the circulation of liposomes and other nanoparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

RGD-modified pH-sensitive liposomes for docetaxel tumor targeting.

PubMed

Chang, Minglu; Lu, Shanshan; Zhang, Fang; Zuo, Tiantian; Guan, Yuanyuan; Wei, Ting; Shao, Wei; Lin, Guimei

2015-05-01

Phosphatidylethanolamine-based pH-sensitive liposomes of various compositions have been described as efficient systems for delivery of therapeutic molecules into tumor cells. The aim of this work was to develop a drug delivery system based on pH-sensitive liposomes (PLPs) that were modified with arginine-glycine-aspartic acid (RGD) peptide to enhance the effectiveness of docetaxel treatment. Docetaxel/coumarin-6 loaded PLPs were prepared by the thin-film dispersion method and characterized in detail, including by particle size, polydispersity, zeta potential and drug encapsulation efficiency. In vitro studies using MCF-7, HepG2and A549 cells were employed to investigate cytotoxicity and cellular uptake of the drug solution or docetaxel/coumarin-6 loaded PLPs. The accumulation of 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD)-labeled liposomes in vivo was studied through tumor section imaging of xenograft mouse models of MCF-7 24h after intravenous administration. The particle size of the non-coated or RGD modified PLPs ranged between 146 and 129nm. Drug release in vitro was modestly prolonged and had good pH sensitivity. In the in vitro study, RGD-coated PLPs showed higher cytotoxicity and cellular uptake relative to non-coated ones. The results of the in vivo study showed that RGD-coated PLPs had higher fluorescence, which suggested a more efficient accumulation than normal PLPs in tumors. In conclusion, these results confirmed RGD-modified PLPs as a potential drug delivery system to achieve controlled release and tumor targeting. Copyright © 2015 Elsevier B.V. All rights reserved.

Pros and cons of the liposome platform in cancer drug targeting.

PubMed

Gabizon, Alberto A; Shmeeda, Hilary; Zalipsky, Samuel

2006-01-01

Coating of liposomes with polyethylene-glycol (PEG) by incorporation in the liposome bilayer of PEG-derivatized lipids results in inhibition of liposome uptake by the reticulo-endothelial system and significant prolongation of liposome residence time in the blood stream. Parallel developments in drug loading technology have improved the efficiency and stability of drug entrapment in liposomes, particularly with regard to cationic amphiphiles such as anthracyclines. An example of this new generation of liposomes is a formulation of pegylated liposomal doxorubicin known as Doxil or Caelyx, whose clinical pharmacokinetic profile is characterized by slow plasma clearance and small volume of distribution. A hallmark of these long-circulating liposomal drug carriers is their enhanced accumulation in tumors. The mechanism underlying this passive targeting effect is the phenomenon known as enhanced permeability and retention (EPR) which has been described in a broad variety of experimental tumor types. Further to the passive targeting effect, the liposome drug delivery platform offers the possibility of grafting tumor-specific ligands on the liposome membrane for active targeting to tumor cells, and potentially intracellular drug delivery. The pros and cons of the liposome platform in cancer targeting are discussed vis-à-vis nontargeted drugs, using as an example a liposome drug delivery system targeted to the folate receptor.

The effect of intestinal bacteria adherence on drug diffusion through solid films under stationary conditions.

PubMed

Rubinstein, A; Radai, R; Friedman, M; Fischer, P; Rokem, J S

1997-04-01

To study the in vitro and in vivo the role of surface bacterial adhesion on the diffusion of model drugs at stationary conditions. Salicylic acid (SA) diffusion through ethyl cellulose (EC) films was measured in vitro in side-by-side diffusion cells with and without E. coli of intestinal origin. Insulin (I) release from paper strips coated or uncoated with pectin films, with or without antibiotic treatment, was measured in vivo in conscious rats after cecal implantation by comparing blood glucose levels at Tmax of the pharmacodynamic effect. During five hours of diffusion studies which were performed immediately following incubation of EC films with bacteria, the diffusion rate of SA throughout the films was 2.72-fold lower in the presence of bacteria compared with the diffusion rate in the control studies conducted without bacteria. The mean blood glucose levels dropped in the rat to 40.6 +/- 21.6% of glucose basal levels within 2.4 +/- 1.4 h when uncoated I solid carriers were used. Glucose levels did not change for pectin-coated dosage forms. After antibiotic treatment which prevented the formation of bacterial biofilm on the surface of the I solid dosage forms, blood glucose levels dropped to 22.0 +/- 4.7% and 50.9 +/- 20.5% of glucose basal levels within 7.4 +/- 2.6 h and 1.8 +/- 0.9 h for pectin uncoated or coated dosage forms, respectively. Maximum bacterial adherence occurred at stationary conditions (RPM = 0), while at maximum agitation (200 RPM), almost no adherence occurred. (a) Bacterial adherence shows down the diffusion rate of SA through EC films; (b) Under stationary conditions bacterial adherence may also interfere with drug release from biodegradable (pectin) films; (c) Successful functioning of biodegradable colon-specific delivery systems depends on agitation and surface friction in the lumen of the colon.

LDRD final report on nanovehicle light-driven propulsion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Anup K.; van Swol, Frank B.; Shelnutt, John Allen

2004-12-01

Having demonstrated the possibility of constructing nanoscale metallic vehicular bodies as described in last year's proposal, our goals have been to make uniform preparations of the metallized lipid assemblies and to determine the feasibility of powering these nanostructures with biological motors that are activated and driven by visible light. We desired that the propulsion system be constructed entirely by self-assembly and powered by a photocatalytic process partially already built into the nanovehicle. The nanovehicle we desire to build is composed of both natural biological components (ATPase, kinesin-microtubules) and biomimetic components (platinized liposomes, photosynthetic membrane) as functional units. The vehicle's bodymore » was originally envisioned to be composed of a surfactant liposomal bilayer coated with platinum nanoparticles, but instead of the expected nanoparticles we were able to grow dendritic 2-nm thick platinum sheets on the liposomes. Now, we have shown that it is possible to completely enclose the liposomes with sheeting to form porous platinum spheres, which show good structural stability as evidenced by their ability to survive the stresses of electron-microscopy sample preparation. Our goals were to control the synthesis of the platinized liposomes well enough to make uniform preparations of the coated individual liposomes and to develop the propulsion system for these nanovehicles a hydrogen-evolving artificial photosynthetic system in the liposomal bilayer that generates the pH gradient across the membrane that is necessary to drive the synthesis of ATP by ATP-synthase incorporated in the membrane. ATP produced would fuel the molecular motor (kinesin) attached to the vehicle, needing only light, storable ADP, phosphate, and an electron donor to be produced by ATP-synthase in the membrane. These research goals appear to be attainable, but growing the uniform preparations of the liposomes coated with dendritic platinum sheeting, a necessary accomplishment that would simplify the task of incorporating and verifying the photosynthetic function of the nanovehicle membrane, has proved to be difficult. The detailed understanding of the relative locations of surfactant and Pt in the liposomal bodies has also forced a change in the nanovehicle design strategies. Nevertheless, we have found no insurmountable obstacles to making these nanovehicles given a larger and longer term research effort. These nanovehicles could potentially respond to chemical gradients, light intensity, and field gradients, in the same manner that magnetic bacteria navigate. The cargo might include decision-making and guidance components, drugs and other biological and chemical agents, explosives, catalytic reactors, and structural materials.« less

Surfactant-stable and pH-sensitive liposomes coated with N-succinyl-chitosan and chitooligosaccharide for delivery of quercetin.

PubMed

Seong, Joon Seob; Yun, Mid Eum; Park, Soo Nam

2018-02-01

Layer-by-layer (LbL) self-assembly of multilayered liposomes is used to improve the stability of conventional liposomes. In this study, the LbL technology was used to prepare novel multilayered liposomes from chitooligosaccharide and N-succinyl-chitosan. We propose that this preparation can be used as a transdermal drug delivery system (TDDS) to enhance stability against surfactants and control drug release. Particle size increased with the number of layers in the multilayer and the zeta potential varied between positive and negative values with alternate deposition of polyelectrolytes. Finally, approximately 300-400nm-thick four-layered liposomes were prepared. These liposomes were more stable against surfactants and showed a relatively high release of quercetin at pH 5.5 than the uncoated liposomes as assessed via in vitro drug release and skin permeation studies. In summary, the multilayered liposomes showed potential for use as a surfactant-stable TDDS that effectively enhanced the permeation of quercetin, a poorly soluble drug, into the skin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physicochemical, total phenols and pectin methylesterase changes on quality maintenance on guava fruit (Psidium guajava L.) coated with candeuba wax solid lipid nanoparticles-xanthan gum.

PubMed

García-Betanzos, Claudia Idalid; Hernández-Sánchez, Humberto; Bernal-Couoh, Tanía Florencia; Quintanar-Guerrero, David; Zambrano-Zaragoza, María de la Luz

2017-11-01

The objective of this work was to evaluate the application of candeuba wax solid lipid nanoparticles (SLN) and xanthan gum (XG) as coatings on guava, and their effect on the fruit's physicochemical and nutritional parameters, complementing a previous publication carried out by Zambrano-Zaragoza et al. (2013). The concentrations of SLN were selected according to those reported as the most (65g/L) and least (75g/L) efficient in post-harvest life preservation, and were compared to a coating of XG and untreated control samples. According to results, the submicron-sized systems used in the coatings with a particle size range of 267-344nm, a polydispersity index <0.2, and zeta potential of -22.8 to -30mV remained stable during 8weeks of storage. The best results were from the fruits coated with 65g/L of SLN and stored at 10°C, as they showed the lowest O 2 and CO 2 respiration rates and, consequently, less weight loss. They also had the best retention of ascorbic acid and total phenol content, with less change in fruit color compared to the control guava and those coated only with XG. These findings indicate that this batch continued their natural maturation process, but at a slower rate than the other samples. The firmness was affected by the activity of the enzyme pectin methylesterase, but results show that the 65g/L coating was efficient in maintaining fruit texture. In contrast, the 75g/L coating produced epoxy in the fruit, causing physiological damage. Finally, the guava coated with XG only had a maturation rate similar to that of the control fruit. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cross-linkable liposomes stabilize a magnetic resonance contrast-enhancing polymeric fastener.

PubMed

Smith, Cartney E; Kong, Hyunjoon

2014-04-08

Liposomes are commonly used to deliver drugs and contrast agents to their target site in a controlled manner. One of the greatest obstacles in the performance of such delivery vehicles is their stability in the presence of serum. Here, we demonstrate a method to stabilize a class of liposomes that load gadolinium, a magnetic resonance (MR) contrast agent, as a model cargo on their surfaces. We hypothesized that the sequential adsorption of a gadolinium-binding chitosan fastener on the liposome surface followed by covalent cross-linking of the lipid bilayer would provide enhanced stability and improved MR signal in the presence of human serum. To investigate this hypothesis, liposomes composed of diyne-containing lipids were assembled and functionalized via chitosan conjugated with a hydrophobic anchor and diethylenetriaminepentaacetic acid (DTPA). This postadsorption cross-linking strategy served to stabilize the thermodynamically favorable association between liposome and polymeric fastener. Furthermore, the chitosan-coated, cross-linked liposomes proved more effective as delivery vehicles of gadolinium than uncross-linked liposomes due to the reduced liposome degradation and chitosan desorption. Overall, this study demonstrates a useful method to stabilize a broad class of particles used for systemic delivery of various molecular payloads.

Cross-Linkable Liposomes Stabilize a Magnetic Resonance Contrast-Enhancing Polymeric Fastener

PubMed Central

2015-01-01

Liposomes are commonly used to deliver drugs and contrast agents to their target site in a controlled manner. One of the greatest obstacles in the performance of such delivery vehicles is their stability in the presence of serum. Here, we demonstrate a method to stabilize a class of liposomes that load gadolinium, a magnetic resonance (MR) contrast agent, as a model cargo on their surfaces. We hypothesized that the sequential adsorption of a gadolinium-binding chitosan fastener on the liposome surface followed by covalent cross-linking of the lipid bilayer would provide enhanced stability and improved MR signal in the presence of human serum. To investigate this hypothesis, liposomes composed of diyne-containing lipids were assembled and functionalized via chitosan conjugated with a hydrophobic anchor and diethylenetriaminepentaacetic acid (DTPA). This postadsorption cross-linking strategy served to stabilize the thermodynamically favorable association between liposome and polymeric fastener. Furthermore, the chitosan-coated, cross-linked liposomes proved more effective as delivery vehicles of gadolinium than uncross-linked liposomes due to the reduced liposome degradation and chitosan desorption. Overall, this study demonstrates a useful method to stabilize a broad class of particles used for systemic delivery of various molecular payloads. PMID:24635565

Arraying of intact liposomes into chemically functionalized microwells.

PubMed

Kalyankar, Nikhil D; Sharma, Manoj K; Vaidya, Shyam V; Calhoun, David; Maldarelli, Charles; Couzis, Alexander; Gilchrist, Lane

2006-06-06

Here, we describe a protocol to bind individual, intact phospholipid bilayer liposomes, which are on the order of 1 microm in diameter, in microwells etched in a regular array on a silicon oxide substrate. The diameter of the wells is on the order of the liposome diameter, so only one liposome is located in each well. The background of the silicon oxide surface is functionalized with a PEG oligomer using the contact printing of a PEG silane to present a surface that resists the adsorption of proteins, lipid material, and liposomes. The interiors of the wells are functionalized with an aminosilane to facilitate the conjugation of biotin, which is then bound to Neutravidin. The avidin-coated well interiors bind the liposomes whose surfaces contain biotinylated lipids. The specific binding of the liposomes to the surface using the biotin-avidin linkage, together with the resistant nature of the background and the physical confinement of the wells, allows the liposomes to remain intact and to not unravel, rupture, and fuse onto the surface. We demonstrate this intact arraying using confocal laser scanning microscopy of fluorophores specifically tagging the microwells, the lipid bilayer, and the aqueous interior of the liposome.

Biocompatibility and light transmission of liposomal lenses.

PubMed

Danion, Anne; Doillon, Charles J; Giasson, Claude J; Djouahra, Saliha; Sauvageau, Patrick; Paradis, Renée; Vermette, Patrick

2007-10-01

To validate the biocompatibility and transmittance properties of contact lenses bearing intact liposomes. These liposomal lenses loaded with therapeutics can be used as ophthalmic drug delivery systems. The biocompatibility of soft contact lenses, coated with liposomes was evaluated through in vitro direct and indirect cytocompatibility assays on human corneal epithelial cells, on reconstructed human corneas and on ex vivo rabbit corneas. The direct and indirect transmission spectra of liposome-covered lenses were also evaluated to test if they transmit all wavelengths of the ultraviolet-visible spectrum, to thereby fulfill their optical function, without gross alteration of the colors perception and with a minimum of light dispersion. Contact lenses bearing layers of stable liposomes did not induce any significant changes in cell viability and in cell growth, compared with lenses bearing no liposome. Elution assays revealed that no cytotoxic compound leaks from the lenses whether bearing liposomes or not. Histological analyses of reconstructed human corneas and ex vivo rabbit corneas directly exposed to liposomal lenses revealed neither alteration to the cell nor to the tissue structures. Contact lenses bearing layers of liposomes did not significantly affect light transmission compared with control lenses without liposome at the wavelength of maximal photopic sensitivity, i.e., 550 nm. In addition, the contact lenses afford more eye protection in the ultraviolet spectrum, compared with the control lenses. Liposomal contact lenses are biocompatible and their transmittance properties are not affected in the visible light range.

The in vitro kinetics of the interactions between PEG-ylated magnetic-fluid-loaded liposomes and macrophages.

PubMed

Martina, Marie-Sophie; Nicolas, Valerie; Wilhelm, Claire; Ménager, Christine; Barratt, Gillian; Lesieur, Sylviane

2007-10-01

Binding and uptake kinetics of magnetic-fluid-loaded liposomes (MFL) by endocytotic cells were investigated in vitro on the model cell-line J774. MFL consisted of unilamellar phosphatidylcholine vesicles (mean hydrodynamic diameter close to 200nm) encapsulating 8-nm nanocrystals of maghemite (gamma-Fe(2)O(3)) and sterically stabilized by introducing 5mol% of distearylphosphatidylcholine poly(ethylene glycol)(2,000) (DSPE-PEG(2,000)) in the vesicle bilayer. The association processes with living macrophages were followed at two levels. On one hand, the lipid vesicles were imaged by confocal fluorescence microscopy. For this purpose 1mol% of rhodamine-marked phosphatidylethanolamine was added to the liposome composition. On the other hand, the iron oxide particles associated with cells were independently quantified by magnetophoresis. All the experiments were similarly performed with PEG-ylated or conventional MFL to point out the role of polymer coating. The results showed cell association with both types of liposomes resulting from binding followed by endocytosis. Steric stabilization by PEG chains reduced binding efficiency limiting the amount of MFL internalized by the macrophages. In contrast, PEG coating did not change the kinetics of endocytosis which exhibited the same first-order rate constant for both conventional and PEG-ylated liposomes. Moreover, lipids and iron oxide particle uptakes were perfectly correlated, indicating that MFL vesicle structure and encapsulation rate were preserved upon cell penetration.

Cerasomes and Bicelles: Hybrid Bilayered Nanostructures with Silica-like Surface in Cancer Theranostics

NASA Astrophysics Data System (ADS)

Hameed, Sadaf; Bhattarai, Pravin; Dai, Zhifei

2018-04-01

Over years, theranostic nanoplatforms have provided a new avenue for the diagnosis and treatment of various cancer types. To this end, a myriad of nanocarriers such as polymeric micelles, liposomes, and inorganic nanoparticles (NPs) with distinct physiochemical and biological properties are routinely investigated for preclinical and clinical studies. So far, liposomes have received great attention for various biomedical applications, however, it still suffers from insufficient morphological stability. On the other hand, inorganic NPs depicting excellent therapeutic ability have failed to address biocompatibility issues. This has raised a serious concern about the clinical approval of multifunctional organic or inorganic-based theranostic agents. Recently, partially silica coated nanohybrids such as cerasomes and bicelles demonstrating both diagnostic and therapeutic ability in a single system, have drawn profound attention as a fascinating novel drug delivery system. Compared with traditional liposomal or inorganic-based nanoformulations, this new and highly stable nanocarriers integrates the functional attributes of biomimetic liposomes and silica NPs, therefore, synergize strengths and functions, or even surpass weaknesses of individual components. This review at its best enlightens the emerging concept of such partially silica coated nanohybrids, fabrication strategies, and theranostic opportunities to combat cancer and related diseases.

Cerasomes and Bicelles: Hybrid Bilayered Nanostructures With Silica-Like Surface in Cancer Theranostics

PubMed Central

Hameed, Sadaf; Bhattarai, Pravin; Dai, Zhifei

2018-01-01

Over years, theranostic nanoplatforms have provided a new avenue for the diagnosis and treatment of various cancer types. To this end, a myriad of nanocarriers such as polymeric micelles, liposomes, and inorganic nanoparticles (NPs) with distinct physiochemical and biological properties are routinely investigated for preclinical and clinical studies. So far, liposomes have received great attention for various biomedical applications, however, it still suffers from insufficient morphological stability. On the other hand, inorganic NPs depicting excellent therapeutic ability have failed to address biocompatibility issues. This has raised a serious concern about the clinical approval of multifunctional organic or inorganic-based theranostic agents. Recently, partially silica coated nanohybrids such as cerasomes and bicelles demonstrating both diagnostic and therapeutic ability in a single system, have drawn profound attention as a fascinating novel drug delivery system. Compared with traditional liposomal or inorganic-based nanoformulations, this new and highly stable nanocarriers integrates the functional attributes of biomimetic liposomes and silica NPs, therefore, synergize strengths and functions, or even surpass weaknesses of individual components. This review at its best enlightens the emerging concept of such partially silica coated nanohybrids, fabrication strategies, and theranostic opportunities to combat cancer and related diseases. PMID:29721494

Inhibition of HIV Virus by Neutralizing Vhh Attached to Dual Functional Liposomes Encapsulating Dapivirine.

PubMed

Wang, Scarlet Xiaoyan; Michiels, Johan; Ariën, Kevin K; New, Roger; Vanham, Guido; Roitt, Ivan

2016-12-01

Although highly active antiretroviral therapy (HAART) has greatly improved the life expectancy of HIV/AIDS patients, the treatment is not curative. It is a global challenge which fosters an urgent need to develop an effective drug or neutralizing antibody delivery approach for the prevention and treatment of this disease. Due to the low density of envelope spikes with restricted mobility present on the surface of HIV virus, which limit the antibody potency and allow virus mutation and escape from the immune system, it is important for a neutralizing antibody to form bivalent or multivalent bonds with the virus. Liposome constructs could fulfil this need due to the flexible mobility of the membrane with its attached antibodies and the capacity for drug encapsulation. In this study, we evaluated the neutralization activity of a range of liposome formulations in different sizes coated with anti-gp120 llama antibody fragments (Vhhs) conjugated via either non-covalent metal chelation or a covalent linkage. The non-covalent construct demonstrated identical binding affinity to HIV-1 envelope glycoprotein gp120 and neutralizing ability for HIV virus as free Vhh. Although covalently linked Vhh showed significant binding affinity to gp120, it unexpectedly had a lower neutralization potency. This may be due to the comparability in size of the viral and liposome particles restricting the number which can be bound to the liposome surface so involving only a fraction of the antibodies, whereas non-covalently attached antibodies dissociate from the surface after acting with gp120 and free the remainder to bind further viruses. Covalently conjugated Vhh might also trigger the cellular uptake of a liposome-virion complex. To explore the possible ability of the antibody-coated liposomes to have a further function, we encapsulated the hydrophobic antiviral drug dapivirine into both of the non-covalently and covalently conjugated liposome formulations, both of which revealed high efficacy in reducing viral replication in vitro. Thus, dual function liposomes may lead to a novel strategy for the prophylaxis of HIV/AIDS by combining the neutralizing activity of Vhh with antiviral effects of high drug concentrations.

Inhibition of HIV Virus by Neutralizing Vhh Attached to Dual Functional Liposomes Encapsulating Dapivirine

NASA Astrophysics Data System (ADS)

Wang, Scarlet Xiaoyan; Michiels, Johan; Ariën, Kevin K.; New, Roger; Vanham, Guido; Roitt, Ivan

2016-07-01

Although highly active antiretroviral therapy (HAART) has greatly improved the life expectancy of HIV/AIDS patients, the treatment is not curative. It is a global challenge which fosters an urgent need to develop an effective drug or neutralizing antibody delivery approach for the prevention and treatment of this disease. Due to the low density of envelope spikes with restricted mobility present on the surface of HIV virus, which limit the antibody potency and allow virus mutation and escape from the immune system, it is important for a neutralizing antibody to form bivalent or multivalent bonds with the virus. Liposome constructs could fulfil this need due to the flexible mobility of the membrane with its attached antibodies and the capacity for drug encapsulation. In this study, we evaluated the neutralization activity of a range of liposome formulations in different sizes coated with anti-gp120 llama antibody fragments (Vhhs) conjugated via either non-covalent metal chelation or a covalent linkage. The non-covalent construct demonstrated identical binding affinity to HIV-1 envelope glycoprotein gp120 and neutralizing ability for HIV virus as free Vhh. Although covalently linked Vhh showed significant binding affinity to gp120, it unexpectedly had a lower neutralization potency. This may be due to the comparability in size of the viral and liposome particles restricting the number which can be bound to the liposome surface so involving only a fraction of the antibodies, whereas non-covalently attached antibodies dissociate from the surface after acting with gp120 and free the remainder to bind further viruses. Covalently conjugated Vhh might also trigger the cellular uptake of a liposome-virion complex. To explore the possible ability of the antibody-coated liposomes to have a further function, we encapsulated the hydrophobic antiviral drug dapivirine into both of the non-covalently and covalently conjugated liposome formulations, both of which revealed high efficacy in reducing viral replication in vitro. Thus, dual function liposomes may lead to a novel strategy for the prophylaxis of HIV/AIDS by combining the neutralizing activity of Vhh with antiviral effects of high drug concentrations.

Innovative bionanocomposite films of edible proteins containing liposome-encapsulated nisin and halloysite nanoclay.

PubMed

Boelter, Juliana Ferreira; Brandelli, Adriano

2016-09-01

Films and coatings based on natural polymers have gained increased interest for food packaging applications. In this work, halloysite and phosphatidylcholine liposomes encapsulating nisin were used to develop nanocomposite films of gelatin and casein. Liposomes prepared with either soybean lecithin or Phospholipon(®) showed particle size ranging from 124 to 178nm and high entrapment efficiency (94-100%). Considering their stability, Phospholipon(®) liposomes with 1.0mg/ml nisin were selected for incorporation into nanocomposite films containing 0.5g/l halloysite. The films presented antimicrobial activity against Listeria monocytogenes, Clostridium perfringens and Bacillus cereus. Scanning electron microscopy revealed that the films had a smooth surface, but showed increased roughness with addition of liposomes and halloysite. Casein films were thinner and slightly yellowish, less rigid and very elastic as compared with gelatin films. Thermogravimetric analysis showed a decrease of the degradation temperature for casein films added with liposomes. The glass transition temperature decreased with addition of liposomes and halloysite. Gelatin and casein films containing nisin-loaded liposomes and halloysite represent an interesting alternative for development of active food packaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Poly(γ-glutamic acid)-coated lipoplexes loaded with Doxorubicin for enhancing the antitumor activity against liver tumors

NASA Astrophysics Data System (ADS)

Qi, Na; Tang, Bo; Liu, Guang; Liang, Xingsi

2017-05-01

The study was to develop poly-γ-glutamic acid (γ-PGA)-coated Doxorubicin (Dox) lipoplexes that enhance the antitumor activity against liver tumors. γ-PGA-coated lipoplexes were performed by electrostatistically attracting to the surface of cationic charge liposomes with anionic γ-PGA. With the increasing of γ-PGA concentration, the particle size of γ-PGA-coated Dox lipoplexes slightly increased, the zeta potential from positive shifted to negative, and the entrapment efficiency (EE) were no significant change. The release rate of γ-PGA-coated Dox lipoplexes slightly increased at acidic pH, the accelerated Dox release might be attributed to greater drug delivery to tumor cells, resulting in a higher antitumor activity. Especially, γ-PGA-coated Dox lipoplexes exhibited higher cellular uptake, significant in vitro cytotoxicity in HepG2 cells, and improved in vivo antitumor efficacy toward HepG2 hepatoma-xenografted nude models in comparison with Dox liposomes and free Dox solution. In addition, the analysis results via flow cytometry showed that γ-PGA-coated Dox lipoplexes induce S phase cell cycle arrest and significantly increased apoptosis rate of HepG2 cells. In conclusion, the presence of γ-PGA on the surface of Dox lipoplexes enhanced antitumor effects of liver tumors.

Synthetic surfactant- and cross-linker-free preparation of highly stable lipid-polymer hybrid nanoparticles as potential oral delivery vehicles.

PubMed

Wang, Taoran; Xue, Jingyi; Hu, Qiaobin; Zhou, Mingyong; Chang, Chao; Luo, Yangchao

2017-06-05

The toxicity associated with concentrated synthetic surfactants and the poor stability at gastrointestinal condition are two major constraints for practical applications of solid lipid nanoparticles (SLN) as oral delivery vehicles. In this study, a synthetic surfactant-free and cross-linker-free method was developed to fabricate effective, safe, and ultra-stable lipid-polymer hybrid nanoparticles (LPN). Bovine serum albumin (BSA) and dextran varying in molecular weights were first conjugated through Maillard reaction and the conjugates were exploited to emulsify solid lipid by a solvent diffusion and sonication method. The multilayer structure was formed by self-assembly of BSA-dextran micelles to envelope solid lipid via a pH- and heating-induced facile process with simultaneous surface deposition of pectin. The efficiency of different BSA-dextran conjugates was systematically studied to prepare LPN with the smallest size, the most homogeneous distribution and the greatest stability. The molecular interactions were characterized by Fourier transform infrared and fluorescence spectroscopies. Both nano spray drying and freeze-drying methods were tested to produce spherical and uniform pectin-coated LPN powders that were able to re-assemble nanoscale structure when redispersed in water. The results demonstrated the promise of a synthetic surfactant- and cross-linker-free technique to prepare highly stable pectin-coated LPN from all natural biomaterials as potential oral delivery vehicles.

Japan Report, Science and Technology

DTIC Science & Technology

1986-07-02

prepared in liposomes of lecithin cholesterol and phosphatidic acid . In order to study whether or not liposome-coated kazusamycin has a cytocidal action...Kazusamycin is a substance in which an unsaturated fatty acid is bonded to an s-lactam ring. Although it does not act on ordinary gram-positive and...organic semiconductor at the heart of the battery is made of polyacene, a polymer with powerful heat and acid resistance and alterable electrical

Transferrin liposomes of docetaxel for brain-targeted cancer applications: formulation and brain theranostics.

PubMed

Sonali; Singh, Rahul Pratap; Singh, Nitesh; Sharma, Gunjan; Vijayakumar, Mahalingam R; Koch, Biplob; Singh, Sanjay; Singh, Usha; Dash, Debabrata; Pandey, Bajarangprasad L; Muthu, Madaswamy S

2016-05-01

Diagnosis and therapy of brain cancer was often limited due to low permeability of delivery materials across the blood-brain barrier (BBB) and their poor penetration into the brain tissue. This study explored the possibility of utilizing theranostic d-alpha-tocopheryl polyethylene glycol 1000 succinate mono-ester (TPGS) liposomes as nanocarriers for minimally invasive brain-targeted imaging and therapy (brain theranostics). The aim of this work was to formulate transferrin conjugated TPGS coated theranostic liposomes, which contain both docetaxel and quantum dots (QDs) for imaging and therapy of brain cancer. The theranostic liposomes with and without transferrin decoration were prepared and characterized for their particle size, polydispersity, morphology, drug encapsulation efficiency, in-vitro release study and brain theranostics. The particle sizes of the non-targeted and targeted theranostic liposomes were found below 200 nm. Nearly, 71% of drug encapsulation efficiency was achieved with liposomes. The drug release from transferrin conjugated theranostic liposomes was sustained for more than 72 h with 70% of drug release. The in-vivo results indicated that transferrin receptor-targeted theranostic liposomes could be a promising carrier for brain theranostics due to nano-sized delivery and its permeability which provided an improved and prolonged brain targeting of docetaxel and QDs in comparison to the non-targeted preparations.

Polydopamine-coated liposomes as pH-sensitive anticancer drug carriers.

PubMed

Zong, Wei; Hu, Ying; Su, Yingchun; Luo, Nan; Zhang, Xunan; Li, Qingchuan; Han, Xiaojun

2016-05-01

Stimuli-responsive drug carriers are considered to play important roles in chemotherapy. We fabricated pH-sensitive polydopamine-protected liposomes (liposome@PDA) drug delivery systems, which were characterised with microscope, scanning electron microscope (SEM), UV-vis spectrometer and Fourier transform infrared (FTIR) technieques. The typical chemotherapeutic agent, 5-fluorouracil (5-FU), was loaded into liposome@PDA capsules. The maximum release percentages of 5-FU are 3.2%, 29.5%, 52.7%, 76.7% in the solution with pH 7.42, 6.87, 4.11 and 3.16, respectively. The in vitro cell cytotoxity experiments were carried out using 5-FU-loaded capsules at pH 6.87 solution, which simulate the true pH around cancerous cells. At 1.5 μM concentration, the free 5-FU, 5-FU-loaded liposome capsules and 5-FU-loaded capsules showed the cell viability of 50.56%, 22.66% and 21.63%, respectively. It confirms that drug-loaded capsules performed better than free drug. The results demonstrate the great potential of liposome@PDA capsules as carriers in biomedical applications.

Secreted phospholipase A(2) as a new enzymatic trigger mechanism for localised liposomal drug release and absorption in diseased tissue.

PubMed

Davidsen, Jesper; Jørgensen, Kent; Andresen, Thomas L; Mouritsen, Ole G

2003-01-10

Polymer-coated liposomes can act as versatile drug-delivery systems due to long vascular circulation time and passive targeting by leaky blood vessels in diseased tissue. We present an experimental model system illustrating a new principle for improved and programmable drug-delivery, which takes advantage of an elevated activity of secretory phospholipase A(2) (PLA(2)) at the diseased target tissue. The secretory PLA(2) hydrolyses a lipid-based proenhancer in the carrier liposome, producing lyso-phospholipids and free fatty acids, which are shown in a synergistic way to lead to enhanced liposome destabilization and drug release at the same time as the permeability of the target membrane is enhanced. Moreover, the proposed system can be made thermosensitive and offers a rational way for developing smart liposome-based drug delivery systems. This can be achieved by incorporating specific lipid-based proenhancers or prodestabilisers into the liposome carrier, which automatically becomes activated by PLA(2) only at the diseased target sites, such as inflamed or cancerous tissue.

Antitumoral activity and toxicity of PEG-coated and PEG-folate-coated pH-sensitive liposomes containing ¹⁵⁹Gd-DTPA-BMA in Ehrlich tumor bearing mice.

PubMed

Soares, Daniel Crístian Ferreira; Cardoso, Valbert Nascimento; de Barros, André Luís Branco; de Souza, Cristina Maria; Cassali, Geovanni Dantas; de Oliveira, Mônica Cristina; Ramaldes, Gilson Andrade

2012-01-23

In the present study, PEG-coated pH-sensitive and PEG-folate-coated pH-sensitive liposomes containing the ¹⁵⁹Gd-DTPA-BMA were prepared and radiolabeled through neutron activation technique, aiming to study the in vivo antitumoral activity and toxicity on mice bearing a previously-developed solid Ehrlich tumor. The treatment efficacy was verified through tumoral volume increase and histomorphometry studies. The toxicity of formulations was investigated through animal weight variations, as well as hematological and biochemical tests. The results showed that after 31 days of treatment, animals treated with radioactive formulations had a lower increase in tumor volume and a significantly higher percentage of necrosis compared with controls revealed by histomorphometry studies. Furthermore, mice treated with radioactive formulations exhibited lower weight gain without significant hematological or biochemical changes, except for toxicity to hepatocytes which requires more detailed studies. From the results obtained to date, we believe that the radioactive formulations can be considered potential therapeutic agents for cancer. Copyright © 2011 Elsevier B.V. All rights reserved.

LDRD final report on light-powered nanovehicles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shelnutt, John Allen; van Swol, Frank B.; Miller, James Edward

2003-11-01

We have investigated the possibility of constructing nanoscale metallic vehicles powered by biological motors or flagella that are activated and powered by visible light. The vehicle's body is to be composed of the surfactant bilayer of a liposome coated with metallic nanoparticles or nanosheets grown together into a porous single crystal. The diameter of the rigid metal vesicles is from about 50 nm to microns. Illumination with visible light activates a photosynthetic system in the bilayer that can generate a pH gradient across the liposomal membrane. The proton gradient can fuel a molecular motor that is incorporated into the membrane.more » Some molecular motors require ATP to fuel active transport. The protein ATP synthase, when embedded in the membrane, will use the pH gradient across the membrane to produce ATP from ADP and inorganic phosphate. The nanoscale vehicle is thus composed of both natural biological components (ATPase, flagellum; actin-myosin, kinesin-microtubules) and biomimetic components (metal vehicle casing, photosynthetic membrane) as functional units. Only light and storable ADP, phosphate, water, and weak electron donor are required fuel components. These nano-vehicles are being constructed by self-assembly and photocatalytic and autocatalytic reactions. The nano-vehicles can potentially respond to chemical gradients and other factors such as light intensity and field gradients, in a manner similar to the way that magnetic bacteria navigate. The delivery package might include decision-making and guidance components, drugs or other biological and chemical agents, explosives, catalytic reactors, and structural materials. We expected in one year to be able only to assess the problems and major issues at each stage of construction of the vehicle and the likely success of fabricating viable nanovehicles with our biomimetic photocatalytic approach. Surprisingly, we have been able to demonstrate that metallized photosynthetic liposomes can indeed be made. We have completed the synthesis of metallized liposomes with photosynthetic function included and studied these structures by electron microscopy. Both platinum and palladium nanosheeting have been used to coat the micelles. The stability of the vehicles to mechanical stress and the solution environment is enhanced by the single-crystalline platinum or palladium coating on the vesicle. With analogous platinized micelles, it is possible to dry the vehicles and re-suspend them with full functionality. However, with the liposomes drying on a TEM grid may cause the platinized liposomes to collapse, although probably stay viable in solution. It remains to be shown whether a proton motive force across the metallized bilayer membrane can be generated and whether we will also be able to incorporate various functional capabilities including ATP synthesis and functional molecular motors. Future tasks to complete the nanovehicles would be the incorporation of ATP synthase into metallized liposomes and the incorporation of a molecular motor into metallized liposomes.« less

Hyaluronic acid-coated liposomes for targeted delivery of paclitaxel, in-vitro characterization and in-vivo evaluation.

PubMed

Ravar, Fatemeh; Saadat, Ebrahim; Gholami, Mehdi; Dehghankelishadi, Pouya; Mahdavi, Mehdi; Azami, Samira; Dorkoosh, Farid A

2016-05-10

Breast cancer is the leading cause of cancer death in women. Chemotherapy is regarded as the most essential strategy in inhibiting the proliferation of tumor cells. Paclitaxel is a widely used taxane; however, the side effects of available Cremophor-based formulations and also the limitations of passive targeting uncovered an essential need to develop tumor-specific targeted nanocarriers. A hyaluronic acid targeted liposomal formulation of paclitaxel was prepared in which, hyaluronic acid was electrostatistically attracted to the surface of liposomes. Liposomes, had a particle size of 106.4±3.2nm, a weakly negative zeta potential of -9.7±0.8mV and an acceptable encapsulation efficiency of 92.1±1.7%. The release profile of liposomes in buffer showed that 95% of PTX was released during 40h. Confocal laser scanning microscopy and flow cytometry analysis showed the greater cellular internalization of coumarin-loaded liposomes compared to free coumarin. MTT assay on 4T1 and T47D cells demonstrated the stronger cytotoxic activity of liposomes in comparison to free paclitaxel. Cell cycle analysis showed that cells were mainly blocked at G2/M phases after 48h treatment with liposomes. In vivo real time imaging on 4T1 tumor-bearing mice revealed that the liposomal formulation mainly accumulated in the tumor area. Liposomes also had better antitumor efficacy against Cremophor-based formulation. In conclusion, hyaluronic acid targeted paclitaxel liposome can serve as a promising targeted formulation of paclitaxel for future cancer chemotherapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Core-shell biopolymer nanoparticle delivery systems: synthesis and characterization of curcumin fortified zein-pectin nanoparticles.

PubMed

Hu, Kun; Huang, Xiaoxia; Gao, Yongqing; Huang, Xulin; Xiao, Hang; McClements, David Julian

2015-09-01

Biopolymer core-shell nanoparticles were fabricated using a hydrophobic protein (zein) as the core and a hydrophilic polysaccharide (pectin) as the shell. Particles were prepared by coating cationic zein nanoparticles with anionic pectin molecules using electrostatic deposition (pH 4). The core-shell nanoparticles were fortified with curcumin (a hydrophobic bioactive molecule) at a high loading efficiency (>86%). The resulting nanoparticles were spherical, relatively small (diameter ≈ 250 nm), and had a narrow size distribution (polydispersity index ≈ 0.24). The encapsulated curcumin was in an amorphous (rather than crystalline form) as detected by differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) and Raman spectra indicated that the encapsulated curcumin interacted with zein mainly through hydrophobic interactions. The nanoparticles were converted into a powdered form that had good water-dispersibility. These core-shell biopolymer nanoparticles could be useful for incorporating curcumin into functional foods and beverages, as well as dietary supplements and pharmaceutical products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Acoustical properties of individual liposome-loaded microbubbles.

PubMed

Luan, Ying; Faez, Telli; Gelderblom, Erik; Skachkov, Ilya; Geers, Bart; Lentacker, Ine; van der Steen, Ton; Versluis, Michel; de Jong, Nico

2012-12-01

A comparison between phospholipid-coated microbubbles with and without liposomes attached to the microbubble surface was performed using the ultra-high-speed imaging camera (Brandaris 128). We investigated 73 liposome-loaded microbubbles (loaded microbubbles) and 41 microbubbles without liposome loading (unloaded microbubbles) with a diameter ranging from 3-10 μm at frequencies ranging from 0.6-3.8 MHz and acoustic pressures ranging from 5-100 kPa. The experimental data showed nearly the same shell elasticity for the loaded and unloaded bubbles, but the shell viscosity was higher for loaded bubbles compared with unloaded bubbles. For loaded bubbles, a higher pressure threshold for the bubble vibrations was noticed. In addition, an "expansion-only" behavior was observed for up to 69% of the investigated loaded bubbles, which mostly occurred at low acoustic pressures (≤30 kPa). Finally, fluorescence imaging showed heterogeneity of liposome distributions of the loaded bubbles. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Sticking to cellulose: exploiting Arabidopsis seed coat mucilage to understand cellulose biosynthesis and cell wall polysaccharide interactions.

PubMed

Griffiths, Jonathan S; North, Helen M

2017-05-01

The cell wall defines the shape of cells and ultimately plant architecture. It provides mechanical resistance to osmotic pressure while still being malleable and allowing cells to grow and divide. These properties are determined by the different components of the wall and the interactions between them. The major components of the cell wall are the polysaccharides cellulose, hemicellulose and pectin. Cellulose biosynthesis has been extensively studied in Arabidopsis hypocotyls, and more recently in the mucilage-producing epidermal cells of the seed coat. The latter has emerged as an excellent system to study cellulose biosynthesis and the interactions between cellulose and other cell wall polymers. Here we review some of the major advances in our understanding of cellulose biosynthesis in the seed coat, and how mucilage has aided our understanding of the interactions between cellulose and other cell wall components required for wall cohesion. Recently, 10 genes involved in cellulose or hemicellulose biosynthesis in mucilage have been identified. These discoveries have helped to demonstrate that xylan side-chains on rhamnogalacturonan I act to link this pectin directly to cellulose. We also examine other factors that, either directly or indirectly, influence cellulose organization or crystallization in mucilage. © 2017 INRA. New Phytologist © 2017 New Phytologist Trust.

Tri-membrane nanoparticles produced by combining liposome fusion and a novel patchwork of bicelles to overcome endosomal and nuclear membrane barriers to cargo delivery.

PubMed

Yamada, Asako; Mitsueda, Asako; Hasan, Mahadi; Ueda, Miho; Hama, Susumu; Warashina, Shota; Nakamura, Takashi; Harashima, Hideyoshi; Kogure, Kentaro

2016-03-01

Membrane fusion is a rational strategy for crossing intracellular membranes that present barriers to liposomal nanocarrier-mediated delivery of plasmid DNA into the nucleus of non-dividing cells, such as dendritic cells. Based on this strategy, we previously developed nanocarriers consisting of a nucleic acid core particle coated with four lipid membranes [Akita, et al., Biomaterials, 2009, 30, 2940-2949]. However, including the endosomal membrane and two nuclear membranes, cells possess three intracellular membranous barriers. Thus, after entering the nucleus, nanoparticles coated with four membranes would still have one lipid membrane remaining, and could impede cargo delivery. Until now, coating a core particle with an odd number of lipid membranes was challenging. To produce nanocarriers with an odd number of lipid membranes, we developed a novel coating method involving lipid nano-discs, also known as bicelles, as a material for packaging DNA in a carrier with an odd number of lipid membranes. In this procedure, bicelles fuse to form an outer coating that resembles a patchwork quilt, which allows the preparation of nanoparticles coated with only three lipid membranes. Moreover, the transfection activity of dendritic cells with these three-membrane nanoparticles was higher than that for nanoparticles coated with four lipid membranes. In summary, we developed novel nanoparticles coated with an odd number of lipid membranes using the novel "patchwork-packaging method" to deliver plasmid DNA into the nucleus via membrane fusion.

Starch-coated magnetic liposomes as an inhalable carrier for accumulation of fasudil in the pulmonary vasculature.

PubMed

Nahar, Kamrun; Absar, Shahriar; Patel, Brijeshkumar; Ahsan, Fakhrul

2014-04-10

In this study, we tested the feasibility of magnetic liposomes as a carrier for pulmonary preferential accumulation of fasudil, an investigational drug for the treatment of pulmonary arterial hypertension (PAH). To develop an optimal inhalable formulation, various magnetic liposomes were prepared and characterized for physicochemical properties, storage stability and in vitro release profiles. Select formulations were evaluated for uptake by pulmonary arterial smooth muscle cells (PASMCs) - target cells - using fluorescence microscopy and HPLC. The efficacy of the magnetic liposomes in reducing hyperplasia was tested in 5-HT-induced proliferated PASMCs. The drug absorption profiles upon intratracheal administration were monitored in healthy rats. Optimized spherical liposomes - with mean size of 170 nm, zeta potential of -35mV and entrapment efficiency of 85% - exhibited an 80% cumulative drug release over 120 h. Fluorescence microscopic study revealed an enhanced uptake of liposomes by PASMCs under an applied magnetic field: the uptake was 3-fold greater compared with that observed in the absence of magnetic field. PASMC proliferation was reduced by 40% under the influence of the magnetic field. Optimized liposomes appeared to be safe when incubated with PASMCs and bronchial epithelial cells. Compared with plain fasudil, intratracheal magnetic liposomes containing fasudil extended the half-life and area under the curve by 27- and 14-fold, respectively. Magnetic-liposomes could be a viable delivery system for site-specific treatment of PAH. Copyright © 2014 Elsevier B.V. All rights reserved.

The protein corona of circulating PEGylated liposomes.

PubMed

Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

2016-02-01

Following systemic administration, liposomes are covered by a 'corona' of proteins, and preserving the surface functionality is challenging. Coating the liposome surface with polyethylene glycol (PEG) is the most widely used anti-opsonization strategy, but it cannot fully preclude protein adsorption. To date, protein binding has been studied following in vitro incubation to predict the fate of liposomes in vivo, while dynamic incubation mimicking in vivo conditions remains largely unexplored. The main aim of this investigation was to determine whether shear stress, produced by physiologically relevant dynamic flow, could influence the liposome-protein corona. The corona of circulating PEGylated liposome was thoroughly compared with that formed by incubation in vitro. Systematic comparison in terms of size, surface charge and quantitative composition was made by dynamic light scattering, microelectrophoresis and nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS). Size of coronas formed under static vs. dynamic incubation did not appreciably differ from each other. On the other side, the corona of circulating liposomes was more negatively charged than its static counterpart. Of note, the variety of protein species in the corona formed in a dynamic flow was significantly wider. Collectively, these results demonstrated that the corona of circulating PEGylated liposomes can be considerably different from that formed in a static fluid. This seems to be a key factor to predict the biological activity of a liposomal formulation in a physiological environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of ca2+ to salicylic acid release in pectin based controlled drug delivery system

NASA Astrophysics Data System (ADS)

Kistriyani, L.; Wirawan, S. K.; Sediawan, W. B.

2016-01-01

Wastes from orange peel are potentially be utilized to produce pectin, which are currently an import commodity. Pectin can be used in making edible film. Edible films are potentially used as a drug delivery system membrane after a tooth extraction. Drug which is used in the drug delivery system is salicylic acid. It is an antiseptic. In order to control the drug release rate, crosslinking process is added in the manufacturing of membrane with CaCl2.2H2O as crosslinker. Pectin was diluted in water and mixed with a plasticizer and CaCl2.2H2O solution at 66°C to make edible film. Then the mixture was dried in an oven at 50 °C. After edible film was formed, it was coated using plasticizer and CaCl2.2H2O solution with various concentration 0, 0.015, 0.03 and 0.05g/mL. This study showed that the more concentration of crosslinker added, the slower release of salicylic acid would be. This was indicated by the value of diffusivites were getting smaller respectively. The addition of crosslinker also caused smaller gels swelling value,which made the membrane is mechanically stronger

Modification of wool surface by liposomes for dyeing with weld.

PubMed

Montazer, Majid; Zolfaghari, Alireza; Toliat, Taibeh; Moghadam, Mohammad Bameni

2009-01-01

In this research work, wool surface has been modified by liposome to investigate its effects on dyeing with weld, a yellow natural dye. To do this, samples were first treated with aluminium sulphate and afterward with different concentrations of liposomes at various temperatures for 30 minutes and, finally, dyed with weld at 75, 85, and 95 degrees C for 30, 45, and 60 minutes. K/S values of fabric samples were calculated and washing, light and rub fastness properties of the samples were indicated. The results proposed that the sample treated with 1% liposomes and dyed at 75 degrees C for 60 min has the highest K/S value. The central composite design (CCD) used for the experimental plan with three variables on the results of color strength and statistical analysis confirms the optimum conditions obtained by the experimental results. It was also found that washing, light, wet, and dry rub fastness properties of samples dyed with weld, including liposomes, have not significantly changed. The results of water drop absorption indicated that the hydrophobicity is higher for the samples pretreated with liposomes. The SEM picture of wool sample treated with mordant and liposomes and finally dyed with weld shows a coated layer on the fiber surface.

Ultrasmall superparamagnetic iron oxide (USPIO)-based liposomes as magnetic resonance imaging probes.

PubMed

Frascione, Daniela; Diwoky, Clemens; Almer, Gunter; Opriessnig, Peter; Vonach, Caroline; Gradauer, Kerstin; Leitinger, Gerd; Mangge, Harald; Stollberger, Rudolf; Prassl, Ruth

2012-01-01

Magnetic liposomes (MLs) are phospholipid vesicles that encapsulate magnetic and/or paramagnetic nanoparticles. They are applied as contrast agents for magnetic resonance imaging (MRI). MLs have an advantage over free magnetic nanocores, in that various functional groups can be attached to the surface of liposomes for ligand-specific targeting. We have synthesized PEG-coated sterically-stabilized magnetic liposomes (sMLs) containing ultrasmall superparamagnetic iron oxides (USPIOs) with the aim of generating stable liposomal carriers equipped with a high payload of USPIOs for enhanced MRI contrast. Regarding iron oxide nanoparticles, we have applied two different commercially available surface-coated USPIOs; sMLs synthesized and loaded with USPIOs were compared in terms of magnetization and colloidal stability. The average diameter size, morphology, phospholipid membrane fluidity, and the iron content of the sMLs were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), fluorescence polarization, and absorption spectroscopy, respectively. A colorimetric assay using potassium thiocyanate (KSCN) was performed to evaluate the encapsulation efficiency (EE%) to express the amount of iron enclosed into a liposome. Subsequently, MRI measurements were carried out in vitro in agarose gel phantoms to evaluate the signal enhancement on T1- and T2-weighted sequences of sMLs. To monitor the biodistribution and the clearance of the particles over time in vivo, sMLs were injected in wild type mice. DLS revealed a mean particle diameter of sMLs in the range between 100 and 200 nm, as confirmed by TEM. An effective iron oxide loading was achieved just for one type of USPIO, with an EE% between 74% and 92%, depending on the initial Fe concentration (being higher for lower amounts of Fe). MRI measurements demonstrated the applicability of these nanostructures as MRI probes. Our results show that the development of sMLs is strictly dependent on the physicochemical characteristics of the nanocores. Once established, sMLs can be further modified to enable noninvasive targeted molecular imaging.

A polymeric fastener can easily functionalize liposome surfaces with gadolinium for enhanced magnetic resonance imaging.

PubMed

Smith, Cartney E; Shkumatov, Artem; Withers, Sarah G; Yang, Binxia; Glockner, James F; Misra, Sanjay; Roy, Edward J; Wong, Chun-Ho; Zimmerman, Steven C; Kong, Hyunjoon

2013-11-26

Common methods of loading magnetic resonance imaging (MRI) contrast agents into nanoparticles often suffer from challenges related to particle formation, complex chemical modification/purification steps, and reduced contrast efficiency. This study presents a simple, yet advanced process to address these issues by loading gadolinium, an MRI contrast agent, exclusively on a liposome surface using a polymeric fastener. The fastener, so named for its ability to physically link the two functional components together, consisted of chitosan substituted with diethylenetriaminepentaacetic acid (DTPA) to chelate gadolinium, as well as octadecyl chains to stabilize the modified chitosan on the liposome surface. The assembly strategy, mimicking the mechanisms by which viruses and proteins naturally anchor to a cell, provided greater T1 relaxivity than liposomes loaded with gadolinium in both the interior and outer leaflet. Gadolinium-coated liposomes were ultimately evaluated in vivo using murine ischemia models to highlight the diagnostic capability of the system. Taken together, this process decouples particle assembly and functionalization and, therefore, has considerable potential to enhance imaging quality while alleviating many of the difficulties associated with multifunctional particle fabrication.

[Liposomes: support for the formation of stable capsules made of reticulated polyelectrolytes or silicum].

PubMed

Germain, M; Paquereau, L; Winterhalter, M; Hochepied, J-F; Fournier, D

2007-03-01

Uses of enzymes for therapeutic purpose or for biosensing require a well-controlled nanoenvironnement to avoid degradation by proteolytic agents, pH variations or dilution effects. A solution is encapsulation under undenaturating conditions into a nanometer sized and stable capsule. The nanometer scall decreases recognition by the reticulo-endothelial system recognition and subsequent immune reaction. Liposomes are the method of choice since they allow protein encapsulation under mild conditions. However they lack in stability. In contrast, other type of capsules exhibit strong stability but with conditions required for formation that are incompatible with enzyme integrity. Here we combine different capsule formation techniques and use liposomes as templates for further stabilization. Here we demonstrate two types of multicomposite capsules. The first type is to coat the liposome surface with polyelectrolytes followed by secondary covalent crosslinking of the polyelectrolytes multilayer. In the second type of capsules we used silica to build an inorganic shell around liposome. Both techniques allow the formation of detergent stable nanocapsules which exhibits properties protective against acetylcholinesterase protein degradation, an enzyme of much interest for pesticide detection.

A Polymeric Fastener can Easily Functionalize Liposome Surfaces with Gadolinium for Enhanced Magnetic Resonance Imaging

PubMed Central

Smith, Cartney E.; Shkumatov, Artem; Withers, Sarah G.; Glockner, James F.; Misra, Sanjay; Roy, Edward J.; Wong, Chun-Ho; Zimmerman, Steven C.; Kong, Hyunjoon

2013-01-01

Common methods of loading magnetic resonance imaging (MRI) contrast agents into nanoparticles often suffer from challenges related to particle formation, complex chemical modification/purification steps, and reduced contrast efficiency. This study presents a simple, yet advanced process to address these issues by loading gadolinium, an MRI contrast agent, exclusively on a liposome surface using a polymeric fastener. The fastener, so named for its ability to physically link the two functional components together, consisted of chitosan substituted with diethylenetriaminepentaacetic acid (DTPA) to chelate gadolinium, as well as octadecyl chains to stabilize the modified chitosan on the liposome surface. The assembly strategy, mimicking the mechanisms by which viruses and proteins naturally anchor to a cell, provided greater T1 relaxivity than liposomes loaded with gadolinium in both the interior and outer leaflet. Gadolinium-coated liposomes were ultimately evaluated in vivo using murine ischemia models to highlight the diagnostic capability of the system. Taken together, this process decouples particle assembly and functionalization, and therefore has considerable potential to enhance imaging quality while alleviating many of the difficulties associated with multifunctional particle fabrication. PMID:24083377

Development of "all natural" layer-by-layer redispersible solid lipid nanoparticles by nano spray drying technology.

PubMed

Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xia, Yan; Nieh, Mu-Ping; Luo, Yangchao

2016-10-01

Solid lipid nanoparticles (SLNs) have gained tremendous attraction as carriers for controlled drug delivery. Despite numerous advances in the field, one long-standing historical challenge for their practical applications remains unmet: redispersibility after drying. In this work, a novel design of SLNs using a layer-by-layer (LbL) technique was developed and the formulations were optimized by surface response methodology (Box-Behnken design). To the best of our knowledge, this is the first study reporting the fabrication of SLNs from all natural ingredients in the absence of any synthetic surfactants or coatings. The SLNs were prepared by a combined solvent-diffusion and hot homogenization method, with soy lecithin as natural emulsifier (first layer), followed by the subsequent coating with sodium caseinate (second layer) and pectin (third layer), both of which are natural food biopolymers. The adsorption of pectin coating onto caseinate was reinforced by hydrophobic and electrostatic interactions induced by a pH-driven process along with thermal treatment. The innovative nano spray drying technology was further explored to obtain ultra-fine powders of SLNs. Compared to uncoated or single-layer coated SLNs powders, which showed severe aggregation after spray drying, the well-separated particles with spherical shape and smooth surface were obtained for layer-by-layer (LbL) SLNs, which were redispersible into water without variation of dimension, shape and morphology. The SLNs were characterized by Fourier transform infrared and high-performance differential scanning calorimetry for their physical properties. The LbL-coated SLNs based on all natural ingredients have promising features for future applications as drug delivery systems, overcoming the major obstacles in conventional spray drying and redispersing SLNs-based formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid phase immobilization of optically responsive liposomes insol-gel materials for chemical and biological sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamanaka, Stacey A.; Charych, Deborah H.; Loy, Douglas A.

1997-04-01

Liposomes enhanced with surface recognition groups have previously been found to have high affinity for heavy metal ions and virus particles with unique fluorescent and colorimetric responses, respectively. These lipid aggregate systems have now been successfully immobilized in a silica matrix via the sol-gel method, affording sensor materials that are robust, are easily handled, and offer optical clarity. The mild processing conditions allow quantitative entrapment of preformed liposomes without modification of the aggregate structure. Lipid extraction studies of immobilized nonpolymerized liposomes showed no lipid leakage in aqueous solution over a period of 3 months. Heavy metal fluorescent sensor materials preparedmore » with 5 percent N-[8-[1-octadecyl-2-(9-(1-pyrenyl)nonyl)-rac-glyceroyl]-3,6-dioxaoctyl]imino acid/distearylphosphatidylcholineliposomes exhibited a 4-50-fold enhancement in sensitivity to various metal ions compared to that of the liposomes in free solution. Through ionic attraction the anionic silicate surface, at the experimental pH of 7.4, may act as a preconcentrator of divalent metal ions, boosting the gel's internal metal concentration. Entrapped sialic acid-coated polydiacetylene liposomes responded with colorimetric signaling to influenza virus X31, although slower than the free liposomes in solution. The successful transport of the virus (50-100 nm diameter) reveals a large pore diameter of the gel connecting the liposome to the bulk solution. The porous and durable silica matrix additionally provides a protective barrier to biological attack (bacterial, fungal) and allows facile recycling of the liposome heavy metal sensor.« less

Exploiting Conjugated Polyelectrolyte Photophysics toward Monitoring Real-Time Lipid Membrane-Surface Interaction Dynamics at the Single-Particle Level.

PubMed

Calver, Christina F; Liu, Hsiao-Wei; Cosa, Gonzalo

2015-11-03

Herein we report the real-time observation of the interaction dynamics between cationic liposomes flowing in solution and a surface-immobilized charged scaffolding formed by the deposition of conjugated polyanion poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene (MPS-PPV) onto 100-nm-diameter SiO2 nanoparticles (NPs). Contact of the freely floating liposomes with the polymer-coated surfaces led to the formation of supported lipid bilayers (SLBs). The interaction of the incoming liposomes with MPS-PPV adsorbed on individual SiO2 nanoparticles promoted the deaggregation of the polymer conformation and led to large emission intensity enhancements. Single-particle total internal reflection fluorescence microscopy studies exploited this phenomenon as a way to monitor the deformation dynamics of liposomes on surface-immobilized NPs. The MPS-PPV emission enhancement (up to 25-fold) reflected on the extent of membrane contact with the surface of the NP and was correlated with the size of the incoming liposome. The time required for the MPS-PPV emission to reach a maximum (ranging from 400 to 1000 ms) revealed the dynamics of membrane deformation and was also correlated with the liposome size. Cryo-TEM experiments complemented these results by yielding a structural view of the process. Immediately following the mixing of liposomes and NPs the majority of NPs had one or more adsorbed liposomes, yet the presence of a fully formed SLB was rare. Prolonged incubation of liposomes and NPs showed completely formed SLBs on all of the NPs, confirming that the liposomes eventually ruptured to form SLBs. We foresee that the single-particle studies we report herein may be readily extended to study membrane dynamics of other lipids including cellular membranes in live cell studies and to monitor the formation of polymer-cushioned SLBs.

Cell mechanics in biomedical cavitation

PubMed Central

Wang, Qianxi; Manmi, Kawa; Liu, Kuo-Kang

2015-01-01

Studies on the deformation behaviours of cellular entities, such as coated microbubbles and liposomes subject to a cavitation flow, become increasingly important for the advancement of ultrasonic imaging and drug delivery. Numerical simulations for bubble dynamics of ultrasound contrast agents based on the boundary integral method are presented in this work. The effects of the encapsulating shell are estimated by adapting Hoff's model used for thin-shell contrast agents. The viscosity effects are estimated by including the normal viscous stress in the boundary condition. In parallel, mechanical models of cell membranes and liposomes as well as state-of-the-art techniques for quantitative measurement of viscoelasticity for a single cell or coated microbubbles are reviewed. The future developments regarding modelling and measurement of the material properties of the cellular entities for cutting-edge biomedical applications are also discussed. PMID:26442142

Near infrared fluorescent chlorophyll nanoscale liposomes for sentinel lymph node mapping

PubMed Central

Fan, Lina; Wu, Qiang; Chu, Maoquan

2012-01-01

Background Sentinel lymph node (SLN) mapping using in vivo near infrared fluorescence imaging has attracted great attention during the past few years. Here we report on the early use of poorly water-soluble chlorophyll with near infrared fluorescence extracted from the leaf of Chimonanthus salicifolius, for mouse axillary SLN mapping. Methods and results To improve the water solubility and SLN targeting of the chlorophyll, we encapsulated the chlorophyll in nanoscale liposomes. The liposome-coated chlorophyll nanocomposites obtained were spherical in shape and had an average diameter of 21.7 ± 6.0 nm. The nanocomposites dispersed well in water, and in aqueous suspension they exhibited brighter near infrared fluorescence than chlorophyll alone. After incubation of the nanocomposites with normal liver cells (QSG-7701) and macrophage cells (Ana-1) for no more than 48 hours, there was no obvious reduction in cell viability. When the nanocomposites were injected intradermally into the paw of a mouse, the axillary SLN was found to be strongly fluorescent and was easily visualized in real time without a requirement for surgery. The intensity of the near infrared fluorescence emitted by the SLN was obviously brighter than that emitted by the SLN of another mouse that had been intradermally injected with chlorophyll alone. Conclusion Our data show that the liposome-coated chlorophyll nanocomposites could have great potential for clinical SLN mapping due to their lack of toxicity, bright near infrared fluorescence, and small diameter. PMID:22787402

Influence of the state of phase of lipid bilayer on the exposure of glucose residues on the surface of liposomes.

PubMed

Villalva, Denise Gradella; Giansanti, Luisa; Mauceri, Alessandro; Ceccacci, Francesca; Mancini, Giovanna

2017-11-01

The presence of carbohydrate-binding proteins (i.e. lectins) on the surface of various bacterial strains and their overexpression in some tumor tissues makes the use of glycosylated liposomes a promising approach for the specific drug delivery in antibacterial and anti-cancer therapies. However, the functionalization of liposome surface with sugar moieties by glycosylated amphiphiles does not ensure the binding of sugar-coated vesicles with lectins. In fact, the composition and properties of lipid bilayer play a pivotal role in the exposure of sugar residues and in the interaction with lectins. The influence of the length of the hydrophilic spacer that links the sugar to liposome surface and of the presence of saturated or unsaturated phospholipids in the lipid bilayer on the ability of glucosylated liposomes to interact with a model lectin, Concanavalin A, was investigated. Our results demonstrate that both the chain length and the prensece of unsaturation, parameters that strongly affect the fluidity of the lipid bilayer, affect agglutination. In particular, agglutination is favored when liposomes are in the gel phase within a defined range of temperature. Moreover, the obtained results confirm that the length of the PEG spacer, that influences both lipid organization and the exposure of sugar moieties to the bulk, plays a crucial role in liposome/lectin interaction. Copyright © 2017 Elsevier B.V. All rights reserved.

Aerosol Stable Peptide-Coated Liposome Nanoparticles: A Proof-of-Concept Study with Opioid Fentanyl in Enhancing Analgesic Effects and Reducing Plasma Drug Exposure

PubMed Central

HOEKMAN, JOHN D; SRIVASTAVA, PRAMOD; HO, RODNEY J Y

2014-01-01

Previous we reported a novel pressurized olfactory drug (POD) delivery device that deposit aerosolized drug preferentially to upper nasal cavity. This POD device provided sustained CNS levels of soluble morphine analgesic effects. However, analgesic onset of less soluble fentanyl was more rapid but brief, likely due to hydrophobic fentanyl redistribution readily back to blood. To determine whether fentanyl incorporated into an aerosol stable liposome that binds to nasal epithelial cells will enhance CNS drug exposure and analgesic effects and reduce plasma exposure, we constructed RGD liposomes anchored with acylated integrin binding peptides (palmitoyl-GRGDS). The RGD liposomes, which assume gel-phase membrane structure at 25°C were stable under the stress of aerosolization as only 2.2 ± 0.5 % calcein leakage detected. The RGD mediated integrin binding of liposome is also verified to be unaffected by aerosolization. Rats treated with fentanyl in RGD-liposome and POD device exhibited greater analgesic effect, compared to the free drug counterpart (AUCeffect = 1387.l vs. 760.1 %MPE*min); while ~20% reduced plasma drug exposure was noted (AUC0-120 = 208.2 vs 284.8 ng*min/ml). Collectively, fentanyl incorporated in RGD-liposomes are physically and biologically stable under aerosolization, enhanced the overall analgesic effects and reduced plasma drug exposure for the first 2 hours. PMID:24909764

Retrograded starch/pectin coated gellan gum-microparticles for oral administration of insulin: A technological platform for protection against enzymatic degradation and improvement of intestinal permeability.

PubMed

Meneguin, Andréia B; Beyssac, Eric; Garrait, Ghislain; Hsein, Hassana; Cury, Beatriz S F

2018-02-01

Gellan gum microparticles coated with colon-specific films based on retrograded starch and pectin was developed for enhancing the oral release of insulin (INS). The system developed promoted an impressive protection of INS (80%) after 120 min of incubation with trypsin and alpha-chymotrypsin, while only 3% of free INS remained intact after the same time, possibility due to the calcium chelating activity of the polymers in inhibiting the proteolytic activity. In vitro INS release in media simulating the gastrointestinal portions revealed a pH-dependent behavior, as well as the significance of the coating in lowering the release rates in relation to their counterparts. The permeability of INS on Caco-2 cells monolayers and excised rat intestine were significantly improved, mainly due to the influence of the anionic polymers on tight junctions opening, along with the excellent mucoadhesive properties of the gellan gum. All these features together contributed greatly to the hypoglycemic effect observed after the oral administration of the INS-loaded MP in diabetic rats, with reduction of up to 51% of blood glucose levels. The important findings of this work should contribute to the advances about the search of alternatives for oral administration of INS. Copyright © 2017. Published by Elsevier B.V.

Impact of dietary fiber coatings on behavior of protein-stabilized lipid droplets under simulated gastrointestinal conditions.

PubMed

Tokle, Tanushree; Lesmes, Uri; Decker, Eric Andrew; McClements, David Julian

2012-01-01

Multilayer emulsions containing lipid droplets coated by lactoferrin (LF) - anionic polysaccharide layers have improved resistance to environmental stresses (such as pH, salt, and temperature), but their behavior within the gastrointestinal tract (GIT) is currently unknown. The objective of this research was therefore to monitor changes in the physicochemical properties and digestibility of these systems under simulated GIT conditions. Primary emulsions (5% corn oil, 0.5% LF) were prepared using a high-pressure homogenizer. Secondary emulsions (5% corn oil, 0.5% LF, 0.5% polysaccharide) were prepared by incorporating alginate, low methoxyl pectin (LMP) or high methoxyl pectin (HMP) into primary emulsions. Emulsions were then subjected to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) conditions in sequence. LF, LF-LMP and LF-HMP emulsions were stable to droplet aggregation in the stomach but aggregated in the small intestine, whereas LF-alginate emulsions aggregated in both the stomach and small intestine. The presence of a dietary fiber coating around the initial lipid droplets had little influence on the total extent of lipid digestion in SIF, but LF-alginate emulsions had a slower initial digestion rate than the other emulsions. These results suggest that the dietary fiber coatings may become detached in the small intestine, or that they were permeable to digestive enzymes. Pepsin was found to have little influence on the physical stability or digestibility of the emulsions. The knowledge obtained from this study is important for the design of delivery systems for encapsulation and release of lipophilic bioactive ingredients.

Microencapsulation and characterization of liposomal vesicles using a supercritical fluid process coupled with vacuum-driven cargo loading.

PubMed

Tsai, Wen-Chyan; Rizvi, Syed S H

2017-06-01

A new technique of liposomal microencapsulation, consisting of supercritical fluid extraction followed by rapid expansion of the supercritical solution and vacuum-driven cargo loading, was successfully developed. It is a continuous flow-through process without usage of any toxic organic solvent. For use as a coating material, the solubility of soy phospholipids in supercritical carbon dioxide was first determined using a dynamic equilibrium system and the data was correlated with the Chrastil model with good agreement. Liposomes were made with D-(+)-glucose as a cargo and their properties were characterized as functions of expansion pressure, temperature, and cargo loading rates. The highest encapsulation efficiency attained was 31.7% at the middle expansion pressure of 12.41MPa, highest expansion temperature of 90°C, and lowest cargo loading rate of 0.25mL/s. The large unilamellar vesicles and multivesicular vesicles were observed to be a majority of the liposomes produced using this eco-friendly process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oleanolic acid liposomes with polyethylene glycol modification: promising antitumor drug delivery

PubMed Central

Gao, Dawei; Tang, Shengnan; Tong, Qi

2012-01-01

Background Oleanolic acid is a pentacyclic triterpene present in many fruits and vegetables, and has received much attention on account of its biological properties. However, its poor solubility and low bioavailability limit its use. The objective of this study was to encapsulate oleanolic acid into nanoliposomes using the modified ethanol injection method. Methods The liposomes contain a hydrophobic oleanolic acid core, an amphiphilic soybean lecithin monolayer, and a protective hydrophilic polyethylene glycol (PEG) coating. During the preparation process, the formulations described were investigated by designing 34 orthogonal experiments as well as considering the effects of different physical characteristics. The four factors were the ratios of drug to soybean phosphatidylcholine (w/w), cholesterol (w/w), PEG-2000 (w/w), and temperature of phosphate-buffered saline at three different levels. We identified the optimized formulation which showed the most satisfactory lipid stability and particle formation. The morphology of the liposomes obtained was determined by transmission electron microscopy and atomic force microscopy. The existence of PEG in the liposome component was validated by Fourier transform infrared spectrum analysis. Results The PEGylated liposomes dispersed individually and had diameters of around 110–200 nm. Encapsulation efficiency was more than 85%, as calculated by high-performance liquid chromatography and Sephadex® gel filtration. Furthermore, when compared with native oleanolic acid, the liposomal formulations showed better stability in vitro. Finally, the cytotoxicity of the oleanolic acid liposomes was evaluated using a microtiter tetrazolium assay. Conclusion These results suggest that PEGylated liposomes would serve as a potent delivery vehicle for oleanolic acid in future cancer therapy. PMID:22848175

Imaging experimental intraabdominal abscesses with 99mTc-PEG liposomes and 99mTc-HYNIC IgG.

PubMed Central

Dams, E T; Reijnen, M M; Oyen, W J; Boerman, O C; Laverman, P; Storm, G; van der Meer, J W; Corstens, F H; van Goor, H

1999-01-01

OBJECTIVE: To evaluate the accuracy of technetium-99m-labeled polyethylene glycol-coated liposomes (99mTc-PEG liposomes) and technetium-99m-labeled nonspecific human immunoglobulin G (99mTc-HYNIC IgG) for the scintigraphic detection of experimental intraabdominal abscesses in comparison with that of a standard agent, gallium-67 citrate. BACKGROUND: Scintigraphic imaging techniques can be very useful for the rapid and accurate localization of intraabdominal abscesses. Two newly developed radiolabeled agents, 99mTc-PEG liposomes and 99mTc-HYNIC IgG, have shown to be excellent agents for imaging experimental focal infection, but have not yet been studied in the detection of abdominal abscesses. METHODS: Intraabdominal abscesses were induced in 42 rats using the cecal ligation and puncture technique. Seven days later, randomized groups of rats received 99mTc-PEG liposomes, 99mTc-HYNIC IgG, or 67Ga citrate intravenously. The rats were imaged up to 24 hours after the injection. The biodistribution of the radiolabel was determined by counting dissected tissues ex vivo. Macroscopic intraabdominal abnormalities and focal uptake on the images were independently scored on a semiquantitative scale. RESULTS: 99mTc-PEG liposomes provided the earliest scintigraphic visualization of the abscess (as soon as 2 hours after the injection vs. 4 hours for the other two agents). Liposomes, IgG, and gallium all showed similarly high absolute uptake in the abscess. Focal uptake of liposomes and gallium correlated best with the extent of the macroscopic abnormalities. CONCLUSIONS: 99mTc-PEG liposomes and 99mTc-HYNIC IgG performed at least as well as the standard agent, 67Ga citrate, in the detection of experimental intraabdominal abscesses, with obvious advantages such as lower radiation exposure and more favorable physical properties. Of the two technetium agents, the liposomes seemed to be superior, providing the earliest diagnostic image and the best correlation with the inflammatory abnormalities. In addition, the preferential localization of radiolabeled PEG liposomes holds promise for targeted delivery of liposome-encapsulated drugs. Images Figure 1. PMID:10203089

Polysaccharide based edible coating on sapota fruit

NASA Astrophysics Data System (ADS)

Menezes, Joslin; Athmaselvi, K. A.

2016-10-01

Sapota fruits are highly perishable and have short shelf life at the ambient conditions. The edible coatings have been used on different agricultural products in order to extend their post harvest life. In the present study, the polysaccharide based edible coating made up of sodium alginate and pectin (2%) was studied on the shelf life of sapota fruits. The coating of the fruits is done by dipping method with two dipping time (2 and 4 min). The both control and coated sapota fruits were stored at refrigerated temperature (4±1°C). The physico-chemical analysis including acidity, total soluble solids, ascorbic acid, pH, weight loss, colour and firmness were measured on 1, 8, 15, 23 and 30th day of storage. There was significant difference (p≤0.05) in these physico-chemical parameters between control and coated sapota fruits with 2 and 4 min dipping time. The sensory analysis of control and coated sapota fruits showed that, the polysaccharide coating with 2 minutes dipping time was effective in maintaining the organoleptic properties of the fruits.

Influence of multilayer rhBMP-2 DNA coating on the proliferation and differentiation of MC3T3-E1 cells seeded on roughed titanium surface.

PubMed

Jiang, Qiao-Hong; Liu, Li; Shen, Jian-Wei; Peel, Sean; Yang, Guo-Li; Zhao, Shi-Fang; He, Fu-Ming

2012-10-01

For bone morphogenetic protein (BMP) gene therapy to be a viable approach for enhancing implant osseointegration clinically, requires the development of efficient nonviral delivery vectors that can coat the implant. This study evaluated a multilayer cationic liposome-DNA complex (LDc) coating as a delivery vehicle for recombinant human BMP-2 (rhBMP-2). Multilayered coatings, comprising hyaluronic acid (HA) and LDc, were fabricated onto titanium using a layer-by-layer (LBL) assembly technique. Preosteoblastic MC3T3-E1 cells were cultured on the roughened titanium surfaces coated with multilayers of HA/LDc, or on uncoated or HA/liposome only surfaces as controls. The amount of rhBMP-2 secreted by the MC3T3-E1 cells and the effect of the various surfaces on cell viability, proliferation, alkaline phosphatase (ALP) activity, osteocalcin (OC) secretion, and calcium deposition were evaluated. Messenger RNA levels of OC, ALP, Runx2, and Osx were also investigated. The results demonstrated that rhBMP-2 protein secreted into culture medium at 3 days was significantly higher than control groups. MC3T3-E1 cells cultured on the HA/LDc coating displayed significantly higher ALP activity and OC secretion at 7 days and 14 days culture, respectively. MC3T3-E1 cells cultured on HA/LDc upregulated expression of the osteoblast differentiation markers, especially on days 12 for OC and on days 6 and 12 for ALP and Osx. In conclusion, MC3T3-E1 cell cultured on the multilayer HA/LDc coating surface can secret rhBMP-2 protein and the protein levels were effective in inducing early osteogenic differentiation. Copyright © 2012 Wiley Periodicals, Inc.

Biocompatibility and therapeutic evaluation of magnetic liposomes designed for self-controlled cancer hyperthermia and chemotherapy.

PubMed

Gogoi, Manashjit; Jaiswal, Manish K; Sarma, Haladhar Dev; Bahadur, Dhirendra; Banerjee, Rinti

2017-06-19

Magnetic liposome-mediated combined chemotherapy and hyperthermia is gaining importance as an effective therapeutic modality for cancer. However, control and maintenance of optimum hyperthermia are major challenges in clinical settings due to the overheating of tissues. To overcome this problem, we developed a novel magnetic liposomes formulation co-entrapping a dextran coated biphasic suspension of La 0.75 Sr 0.25 MnO 3 (LSMO) and iron oxide (Fe 3 O 4 ) nanoparticles for self-controlled hyperthermia and chemotherapy. However, the general apprehension about biocompatibility and safety of the newly developed formulation needs to be addressed. In this work, in vitro and in vivo biocompatibility and therapeutic evaluation studies of the novel magnetic liposomes are reported. Biocompatibility study of the magnetic liposomes formulation was carried out to evaluate the signs of preliminary systemic toxicity, if any, following intravenous administration of the magnetic liposomes in Swiss mice. Therapeutic efficacy of the magnetic liposomes formulation was evaluated in the fibrosarcoma tumour bearing mouse model. Fibrosarcoma tumour-bearing mice were subjected to hyperthermia following intratumoral injection of single or double doses of the magnetic liposomes with or without chemotherapeutic drug paclitaxel. Hyperthermia (three spurts, each at 3 days interval) with drug loaded magnetic liposomes following single dose administration reduced the growth of tumours by 2.5 fold (mean tumour volume 2356 ± 550 mm 3 ) whereas the double dose treatment reduced the tumour growth by 3.6 fold (mean tumour volume 1045 ± 440 mm 3 ) compared to their corresponding control (mean tumour volume 3782 ± 515 mm 3 ). At the end of the tumour efficacy studies, the presence of MNPs was studied in the remnant tumour tissues and vital organs of the mice. No significant leaching or drainage of the magnetic liposomes during the study was observed from the tumour site to the other vital organs of the body, suggesting again the potential of the novel magnetic liposomes formulation for possibility of developing as an effective modality for treatment of drug resistant or physiologically vulnerable cancer.

Control over Silica Particle Growth and Particle–Biomolecule Interactions Facilitates Silica Encapsulation of Mammalian Cells with Thickness Control

DOE PAGES

Johnston, Robert K.; Harper, Jason C.; Tartis, Michaelann S.

2017-07-13

Over the past 20 years, many strategies utilizing sol–gel chemistry to integrate biological cells into silica-based materials have been reported. One such strategy, Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition, shows promise as an efficient encapsulation technique due to the ability to vary the silica encapsulation morphology obtained by this process through variation of SG-CViL reaction conditions. In this report, we develop SG-CViL as a tunable, multi-purpose silica encapsulation strategy by investigating the mechanisms governing both silica particle generation and subsequent interaction with phospholipid assemblies (liposomes and living cells). Using Dynamic Light Scattering (DLS) measurements, linear and exponential silica particlemore » growth dynamics were observed which were dependent on deposition buffer ion constituents and ion concentration. Silica particle growth followed a cluster–cluster growth mechanism at acidic pH, and a monomer-cluster growth mechanism at neutral to basic pH. Increasing silica sol aging temperature resulted in higher rates of particle growth and larger particles. DLS measurements employing PEG-coated liposomes and cationic liposomes, serving as model phospholipid assemblies, revealed that electrostatic interactions promote more stable liposome–silica interactions than hydrogen bonding and facilitate silica coating on suspension cells. However, continued silica reactivity leads to aggregation of silica-coated suspension cells, revealing the need for cell isolation to tune deposited silica thickness. As a result, utilizing these mechanistic study insights, silica was deposited onto adherent HeLa cells under biocompatible conditions with micrometer-scale control over silica thickness, minimal cell manipulation steps, and retained cell viability over several days.« less

Control over Silica Particle Growth and Particle–Biomolecule Interactions Facilitates Silica Encapsulation of Mammalian Cells with Thickness Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, Robert K.; Harper, Jason C.; Tartis, Michaelann S.

Over the past 20 years, many strategies utilizing sol–gel chemistry to integrate biological cells into silica-based materials have been reported. One such strategy, Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition, shows promise as an efficient encapsulation technique due to the ability to vary the silica encapsulation morphology obtained by this process through variation of SG-CViL reaction conditions. In this report, we develop SG-CViL as a tunable, multi-purpose silica encapsulation strategy by investigating the mechanisms governing both silica particle generation and subsequent interaction with phospholipid assemblies (liposomes and living cells). Using Dynamic Light Scattering (DLS) measurements, linear and exponential silica particlemore » growth dynamics were observed which were dependent on deposition buffer ion constituents and ion concentration. Silica particle growth followed a cluster–cluster growth mechanism at acidic pH, and a monomer-cluster growth mechanism at neutral to basic pH. Increasing silica sol aging temperature resulted in higher rates of particle growth and larger particles. DLS measurements employing PEG-coated liposomes and cationic liposomes, serving as model phospholipid assemblies, revealed that electrostatic interactions promote more stable liposome–silica interactions than hydrogen bonding and facilitate silica coating on suspension cells. However, continued silica reactivity leads to aggregation of silica-coated suspension cells, revealing the need for cell isolation to tune deposited silica thickness. As a result, utilizing these mechanistic study insights, silica was deposited onto adherent HeLa cells under biocompatible conditions with micrometer-scale control over silica thickness, minimal cell manipulation steps, and retained cell viability over several days.« less

Composite coating of alginate-olive oil enriched with antioxidants enhances postharvest quality and shelf life of Ber fruit (Ziziphus mauritiana Lamk. Var. Gola).

PubMed

Ramana Rao, T V; Baraiya, Nilanjana S; Vyas, Pinal B; Patel, Dhara M

2016-01-01

The present study has been carried out to evaluate the effect of a composite edible coating of 2 % Sodium alginate and 0.2 % Olive oil with combination of 1 % ascorbic acid and 1 % citric acid on the post harvest nutritional quality and shelf life of Ber fruit stored at 25 ± 2 °C and 65 % R.H. The coatings reduced the decay occurrence, weight loss, accumulation of total soluble solids (TSS) and total sugars in Ber fruit and enhanced the level of antioxidants. The delayed activity of polygalacturonase (PG), Pectate lyase (PL) and Pectin methyl esterase (PME) was noticed in coated fruits than that of the control fruit indicating the reduced softening and ripening process. These findings suggest that the composite edible coating tested under the current study has the potential to control decaying incidence of Ber fruit, extends its storage life and also improves its valuable nutritional characteristics.

Pectin-coated boron nitride nanotubes: In vitro cyto-/immune-compatibility on RAW 264.7 macrophages.

PubMed

Rocca, Antonella; Marino, Attilio; Del Turco, Serena; Cappello, Valentina; Parlanti, Paola; Pellegrino, Mario; Golberg, Dmitri; Mattoli, Virgilio; Ciofani, Gianni

2016-04-01

Boron nitride nanotubes (BNNTs) represent a new opportunity for drug delivery and clinical therapy. The present work has the objective to investigate pectin-coated BNNTs (P-BNNTs) for their biocompatibility on macrophage cultures, since these cells are among the first components of the immune system to interact with administered nanoparticles. As first step, the potential toxicity of P-BNNTs is verified in terms of proliferation, oxidative stress induction and apoptosis/necrosis phenomena. Thereafter, the modulation of immune cell response following P-BNNT exposure is evaluated at gene and protein level, in particular focusing on cytokine release. Finally, P-BNNT internalization is assessed through transmission electron microscopy and confocal microscopy. The results proved that P-BNNTs are not toxic for macrophages up to 50 μg/ml after 24 h of incubation. The cytokine expression is not affected by P-BNNT administration both at gene and protein level. Moreover, P-BNNTs are internalized by macrophages without impairments of the cell structures. Collected data suggest that P-BNNTs cause neither adverse effects nor inflammation processes in macrophages. These findings represent the first and fundamental step in immune compatibility evaluation of BNNTs, mandatory before any further pre-clinical testing. Copyright © 2016 Elsevier B.V. All rights reserved.

Magnetic iron oxide nanoparticles mediated gene therapy for breast cancer--an in vitro study.

PubMed

Wei, Weizhong; Xu, Chunfang; Wu, Hua

2006-01-01

The aim of this study was to evaluate the feasibility and efficacy of using TRAIL gene to treat breast cancer mediated with a novel carrier - magnetic iron oxide nanoparticles (poly-MAG-1000) coated with PEI. The magnetic iron oxide nanoparticles were used as gene carrier to transfect TRAIL gene into MCF-7 cells. The polyMAG-1000 without TRAIL gene was transfected into the tumor cells as negative control. TRAIL gene transfection with liposome as carrier served as positive control. The apoptosis of cells was detected with TUNEL method. The apoptosis ratio of tumor cells was measured with flow cytometry (FCM). It was found that the apoptosis occurred in the tumor cells after transfection of TRAIL gene mediated by both polyMAG-1000 and liposome. The apoptosis ratio in the group with polyMAG-1000 as gene carrier was (25.11+/-2.85) %, whereas it was (5.06+/- 1.05) % in the control group with polyMAG-1000 (P<0.01). The apoptosis ratio was as low as (18.31+/-2.44) % in the group with liposome as gene carrier (P<0.05, as compared with the group with polyMAG-1000 as gene carrier). It is suggested that TRAIL gene may induce apoptosis in MCF-7 breast cancer cells. The magnetic iron oxide nanoparticles coated with PEI may be a potential gene carrier with high transfection efficacy for cancer gene therapy..

Chitosan-coated liposome dry-powder formulations loaded with ghrelin for nose-to-brain delivery.

PubMed

Salade, Laurent; Wauthoz, Nathalie; Vermeersch, Marjorie; Amighi, Karim; Goole, Jonathan

2018-06-11

The nose-to-brain delivery of ghrelin loaded in liposomes is a promising approach for the management of cachexia. It could limit the plasmatic degradation of ghrelin and provide direct access to the brain, where ghrelin's specific receptors are located. Anionic liposomes coated with chitosan in either a liquid or a dry-powder formulation were compared. The powder formulation showed stronger adhesion to mucins (89 ± 4% vs 61 ± 4%), higher ghrelin entrapment efficiency (64 ± 2% vs 55 ± 4%), higher enzymatic protection against trypsin (26 ± 2% vs 20 ± 3%) and lower ghrelin storage degradation at 25°C (2.67 ± 1.1% vs 95.64 ± 0.85% after 4 weeks). The powder formulation was also placed in unit-dose system devices that were able to generate an appropriate aerosol characterized by a Dv50 of 38 ± 6 µm, a limited percentage of particles smaller than 10 µm of 4 ± 1% and a reproducible mass delivery (CV: 1.49%). In addition, the device was able to deposit a large amount of powder (52.04% w/w) in the olfactory zone of a 3D-printed nasal cast. The evaluated combination of the powder formulation and the device could provide a promising treatment for cachexia. Copyright © 2018. Published by Elsevier B.V.

Progression of pectinate ligament dysplasia over time in two populations of Flat-Coated Retrievers.

PubMed

Pearl, Rose; Gould, David; Spiess, Bernhard

2015-01-01

Two of the authors (DG, BS) independently observed that a number of Flat-Coated Retrievers (FCRs) previously unaffected by pectinate ligament dysplasia (PLD) appeared to develop the condition later in life. This study was instigated to investigate progression of PLD within individual dogs over time. Flat-Coated Retrievers that had previously undergone gonioscopy under the UK/ECVO hereditary eye schemes were included in the study. A second gonioscopic examination was performed 1.92-12.58 years later (mean 6, median 5.75 years) and the results compared. 39 FCR (17 males, 22 females) in the UK and 57 FCR (27 males, 30 females) in Switzerland were included. Slit-lamp biomicroscopy, indirect ophthalmoscopy, and gonioscopy were performed in all dogs. Gonioscopy allowed classification as either unaffected or affected; percentage of the iridocorneal drainage angle (ICA) affected by PLD was determined, before calculating progression observed as mild, moderate, or severe. 39 of 96 (40.6%) dogs demonstrated progression of PLD (P < 0.0001). Of these, 13 of 96 (13.5%) were classified as mild progression (from either unaffected to 10-20% or 10-20% to 20-90% ICA affected). Progression was more extensive in 26 of 96 (27.1%) dogs (P < 0.0001), of which 12 of 96 (12.5%) went from unaffected to severe PLD of >90% ICA affected, consistent with a high risk of glaucoma. To the authors' knowledge, this is the first report describing progression of PLD in individual dogs over time, in a breed affected by primary, angle closure glaucoma. © 2013 American College of Veterinary Ophthalmologists.

Magnetic liposomes for colorectal cancer cells therapy by high-frequency magnetic field treatment

NASA Astrophysics Data System (ADS)

Hardiansyah, Andri; Huang, Li-Ying; Yang, Ming-Chien; Liu, Ting-Yu; Tsai, Sung-Chen; Yang, Chih-Yung; Kuo, Chih-Yu; Chan, Tzu-Yi; Zou, Hui-Ming; Lian, Wei-Nan; Lin, Chi-Hung

2014-09-01

In this study, we developed the cancer treatment through the combination of chemotherapy and thermotherapy using doxorubicin-loaded magnetic liposomes. The citric acid-coated magnetic nanoparticles (CAMNP, ca. 10 nm) and doxorubicin were encapsulated into the liposome (HSPC/DSPE/cholesterol = 12.5:1:8.25) by rotary evaporation and ultrasonication process. The resultant magnetic liposomes ( ca. 90 to 130 nm) were subject to characterization including transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), zeta potential, Fourier transform infrared (FTIR) spectrophotometer, and fluorescence microscope. In vitro cytotoxicity of the drug carrier platform was investigated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using L-929 cells, as the mammalian cell model. In vitro cytotoxicity and hyperthermia (inductive heating) studies were evaluated against colorectal cancer (CT-26 cells) with high-frequency magnetic field (HFMF) exposure. MTT assay revealed that these drug carriers exhibited no cytotoxicity against L-929 cells, suggesting excellent biocompatibility. When the magnetic liposomes with 1 μM doxorubicin was used to treat CT-26 cells in combination with HFMF exposure, approximately 56% cells were killed and found to be more effective than either hyperthermia or chemotherapy treatment individually. Therefore, these results show that the synergistic effects between chemotherapy (drug-controlled release) and hyperthermia increase the capability to kill cancer cells.

In Vivo Biomolecule Corona around Blood-Circulating, Clinically Used and Antibody-Targeted Lipid Bilayer Nanoscale Vesicles.

PubMed

Hadjidemetriou, Marilena; Al-Ahmady, Zahraa; Mazza, Mariarosa; Collins, Richard F; Dawson, Kenneth; Kostarelos, Kostas

2015-08-25

The adsorption of proteins and their layering onto nanoparticle surfaces has been called the "protein corona". This dynamic process of protein adsorption has been extensively studied following in vitro incubation of many different nanoparticles with plasma proteins. However, the formation of protein corona under dynamic, in vivo conditions remains largely unexplored. Extrapolation of in vitro formed protein coronas to predict the fate and possible toxicological burden from nanoparticles in vivo is of great interest. However, complete lack of such direct comparisons for clinically used nanoparticles makes the study of in vitro and in vivo formed protein coronas of great importance. Our aim was to study the in vivo protein corona formed onto intravenously injected, clinically used liposomes, based on the composition of the PEGylated liposomal formulation that constitutes the anticancer agent Doxil. The formation of in vivo protein corona was determined after the recovery of the liposomes from the blood circulation of CD-1 mice 10 min postinjection. In comparison, in vitro protein corona was formed by the incubation of liposomes in CD-1 mouse plasma. In vivo and in vitro formed protein coronas were compared in terms of morphology, composition and cellular internalization. The protein coronas on bare (non-PEGylated) and monoclonal antibody (IgG) targeted liposomes of the same lipid composition were also comparatively investigated. A network of linear fibrillary structures constituted the in vitro formed protein corona, whereas the in vivo corona had a different morphology but did not appear to coat the liposome surface entirely. Even though the total amount of protein attached on circulating liposomes correlated with that observed from in vitro incubations, the variety of molecular species in the in vivo corona were considerably wider. Both in vitro and in vivo formed protein coronas were found to significantly reduce receptor binding and cellular internalization of antibody-conjugated liposomes; however, the in vivo corona formation did not lead to complete ablation of their targeting capability.

Hybrid lipid-based nanostructures

NASA Astrophysics Data System (ADS)

Dayani, Yasaman

Biological membranes serve several important roles, such as structural support of cells and organelles, regulation of ionic and molecular transport, barriers to non-mediated transport, contact between cells within tissues, and accommodation of membrane proteins. Membrane proteins and other vital biomolecules incorporated into the membrane need a lipid membrane to function. Due to importance of lipid bilayers and their vital function in governing many processes in the cell, the development of various models as artificial lipid membranes that can mimic cell membranes has become a subject of great interest. Using different models of artificial lipid membranes, such as liposomes, planar lipid bilayers and supported or tethered lipid bilayers, we are able to study many biophysical processes in biological membranes. The ability of different molecules to interact with and change the structure of lipid membranes can be also investigated in artificial lipid membranes. An important application of lipid bilayer-containing interfaces is characterization of novel membrane proteins for high throughput drug screening studies to investigate receptor-drug interactions and develop biosensor systems. Membrane proteins need a lipid bilayer environment to preserve their stability and functionality. Fabrication of materials that can interact with biomolecules like proteins necessitates the use of lipid bilayers as a mimic of cell membranes. The objective of this research is to develop novel hybrid lipid-based nanostructures mimicking biological membranes. Toward this aim, two hybrid biocompatible structures are introduced: lipid bilayer-coated multi-walled carbon nanotubes (MWCNTs) and hydrogel-anchored liposomes with double-stranded DNA anchors. These structures have potential applications in biosensing, drug targeting, drug delivery, and biophysical studies of cell membranes. In the first developed nanostructure, lipid molecules are covalently attached to the surfaces of MWCNTs, and then, using a sonication process, a uniform lipid bilayer that supports the incorporation of membrane proteins is formed. These bilayer-coated carbon nanotubes are highly dispersible and stable in aqueous solution, and they can be used in development of various biosensors and energy producing devices. In the other hybrid nanostructure, the lipid bilayer of a liposome is covalently anchored to a biocompatible poly(ethylene) glycol (PEG) hydrogel core using double-stranded DNA (dsDNA) linkers. Release studies shows that nano-size hydrogel-anchored liposomes are exceptionally stable, and they can be used as biomimetic model membranes that mimic the connectivity between the cytoskeleton and the plasma membrane. After lipid bilayer removal, dsDNA linkers can provide programmable nanogels decorated with oligonucleotides with potential sites for further molecular assembly. These stable nanostructures can be useful for oligonucleotide and drug delivery applications. The developed hydrogel-anchored liposomes are exploited for encapsulation and intracellular delivery of therapeutic peptide. Peptides with anti-cancer properties are successfully encapsulated in hydrogel core of pH-sensitive liposomes during rehydration process. Liposomes release their cargo at acidic pH. Confocal microscopy confirms the intracellular delivery of liposomes through an endocytotic pathway.

Effect of superparamagnetic iron oxide nanoparticles on fluidity and phase transition of phosphatidylcholine liposomal membranes

PubMed Central

Santhosh, Poornima Budime; Drašler, Barbara; Drobne, Damjana; Kreft, Mateja Erdani; Kralj, Slavko; Makovec, Darko; Ulrih, Nataša Poklar

2015-01-01

Superparamagnetic iron oxide nanoparticles (SPIONs) with multifunctional properties have shown great promise in theranostics. The aim of our work was to compare the effects of SPIONs on the fluidity and phase transition of the liposomal membranes prepared with zwitterionic phosphatidylcholine lipids. In order to study if the surface modification of SPIONs has any influence on these membrane properties, we have used four types of differently functionalized SPIONs, such as: plain SPIONs (primary size was shown to bê11 nm), silica-coated SPIONs, SPIONs coated with silica and functionalized with positively charged amino groups or negatively charged carboxyl groups (the primary size of all the surface-modified SPIONs was ~20 nm). Small unilamellar vesicles prepared with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine lipids and multilamellar vesicles prepared with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine lipids were encapsulated or incubated with the plain and surface-modified SPIONs to determine the fluidity and phase transition temperature of the bilayer lipids, respectively. Fluorescent anisotropy and differential scanning calorimetric measurements of the liposomes that were either encapsulated or incubated with the suspension of SPIONs did not show a significant difference in the lipid ordering and fluidity; though the encapsulated SPIONs showed a slightly increased effect on the fluidity of the model membranes in comparison with the incubated SPIONs. This indicates the low potential of the SPIONs to interact with the nontargeted cell membranes, which is a desirable factor for in vivo applications. PMID:26491286

Encapsulated microbubbles and echogenic liposomes for contrast ultrasound imaging and targeted drug delivery

PubMed Central

Paul, Shirshendu; Nahire, Rahul; Mallik, Sanku; Sarkar, Kausik

2014-01-01

Micron- to nanometer-sized ultrasound agents, like encapsulated microbubbles and echogenic liposomes, are being developed for diagnostic imaging and ultrasound mediated drug/gene delivery. This review provides an overview of the current state of the art of the mathematical models of the acoustic behavior of ultrasound contrast microbubbles. We also present a review of the in vitro experimental characterization of the acoustic properties of microbubble based contrast agents undertaken in our laboratory. The hierarchical two-pronged approach of modeling contrast agents we developed is demonstrated for a lipid coated (Sonazoid™) and a polymer shelled (poly D-L-lactic acid) contrast microbubbles. The acoustic and drug release properties of the newly developed echogenic liposomes are discussed for their use as simultaneous imaging and drug/gene delivery agents. Although echogenicity is conclusively demonstrated in experiments, its physical mechanisms remain uncertain. Addressing questions raised here will accelerate further development and eventual clinical approval of these novel technologies. PMID:26097272

Microencapsulation structures based on protein-coated liposomes obtained through electrospraying for the stabilization and improved bioaccessibility of curcumin.

PubMed

Gómez-Mascaraque, Laura G; Casagrande Sipoli, Caroline; de La Torre, Lucimara Gaziola; López-Rubio, Amparo

2017-10-15

Novel food-grade hybrid encapsulation structures based on the entrapment of phosphatidylcholine liposomes, within a WPC matrix through electrospraying, were developed and used as delivery vehicles for curcumin. The loading capacity and encapsulation efficiency of the proposed system was studied, and the suitability of the approach to stabilize curcumin and increase its bioaccessibility was assessed. Results showed that the maximum loading capacity of the liposomes was around 1.5% of curcumin, although the loading capacity of the hybrid microencapsulation structures increased with the curcumin content by incorporation of curcumin microcrystals upon electrospraying. Microencapsulation of curcumin within the proposed hybrid structures significantly increased its bioaccessibility (∼1.7-fold) compared to the free compound, and could successfully stabilize it against degradation in PBS (pH=7.4). The proposed approach thus proved to be a promising alternative to produce powder-like functional ingredients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Peritoneal retention of liposomes: Effects of lipid composition, PEG coating and liposome charge.

PubMed

Dadashzadeh, S; Mirahmadi, N; Babaei, M H; Vali, A M

2010-12-01

In the treatment of peritoneal carcinomatosis, systemic chemotherapy is not quite effective due to the poor penetration of cytotoxic agents into the peritoneal cavity, whereas intraperitoneal administration of chemotherapeutic agents is generally accompanied by quick absorption of the free drug from the peritoneum. Local delivery of drugs with controlled-release delivery systems like liposomes could provide sustained, elevated drug levels and reduce local and systemic toxicity. In order to achieve an ameliorated liposomal formulation that results in higher peritoneal levels of the drug and retention, vesicles composed of different phospholipid compositions (distearoyl [DSPC]; dipalmitoyl [DPPC]; or dimiristoylphosphatidylcholine [DMPC]) and various charges (neutral; negative, containing distearoylphosphatidylglycerol [DSPG]; or positive, containing dioleyloxy trimethylammonium propane [DOTAP]) were prepared at two sizes of 100 and 1000nm. The effect of surface hydrophilicity was also investigated by incorporating PEG into the DSPC-containing neutral and charged liposomes. Liposomes were labeled with (99m)Tc and injected into mouse peritoneum. Mice were then sacrificed at eight different time points, and the percentage of injected radiolabel in the peritoneal cavity and the tissue distribution in terms of the percent of the injected dose/gram of tissue (%ID/g) were obtained. The ratio of the peritoneal AUC to the free label ranged from a minimum of 4.95 for DMPC/CHOL (cholesterol) 100nm vesicles to a maximum of 24.99 for DSPC/CHOL/DOTAP 1000nm (DOTAP 1000) vesicles. These last positively charged vesicles had the greatest peritoneal level; moreover, their level remained constant at approximately 25% of the injected dose from 2 to 48h. Among the conventional (i.e., without PEG) 100nm liposomes, the positively charged vesicles again showed the greatest retention. Incorporation of PEG at this size into the lipid structures augmented the peritoneal level, particularly for negatively charged liposomes. The positively charged PEGylated vesicles (DOTAP/PEG 100) had the second-greatest peritoneal level after DOTAP 1000; however, their peritoneal-to-blood AUC ratio was low (3.05). Overall, among the different liposomal formulations, the positively charged conventional liposomes (100 and 1000nm) provided greater peritoneal levels and retention. DOTAP/PEG100 may also be a more efficient formulation because this formulation can provide a high level of anticancer drug into the peritoneal cavity and also can passively target the primary tumor. Copyright © 2010 Elsevier B.V. All rights reserved.

pH-Sensitive carboxymethyl chitosan-modified cationic liposomes for sorafenib and siRNA co-delivery.

PubMed

Yao, Yao; Su, Zhihui; Liang, Yanchao; Zhang, Na

2015-01-01

Combination of chemotherapeutic drug and small interfering RNA (siRNA) can affect multiple disease pathways and has been proven effective in suppressing tumor progression. Co-delivery of drug and siRNA within a same nanocarrier is a vital means in this field. The present study aimed at the development of a pH-sensitive liposome to co-deliver drug and siRNA to tumor region. Driven by the electrostatic interaction, the pH-sensitive material, carboxymethyl chitosan (CMCS), was coated onto the surface of the cationic liposome (CL) preloaded with sorafenib (Sf) and siRNA (Si). To evaluate whether the resulting CMCS-modified Sf and siRNA co-delivery cationic liposome (CMCS-SiSf-CL) enhanced antitumor efficiency after systematic administration, in vitro and in vivo experiments were evaluated in HepG2 cells and the H22 cells-bearing Kunming mice model. The experimental results demonstrated that CMCS-SiSf-CL was able to condense siRNA efficiently and protect siRNA from being degraded by serum and RNase. The release rate of Sf from CMCS-modified liposome exhibited pH-sensitive release behavior. Furthermore, in vitro cellular uptake results showed that CMCS-SiSf-CL yielded higher fluorescence intensity at pH 6.5 than at pH 7.4, and that siRNA could be delivered to tumor site by CMCS-SiSf-CL in vivo. The in vivo antitumor efficacy showed that CMCS-Sf-CL inhibits tumor growth effectively when compared with free Sf solution. In current experimental conditions, this liposomal formulation did not show significant toxicity both in vitro and in vivo. Therefore, co-delivering Sf with siRNA by CMCS-SiSf-CL might provide a promising approach for tumor therapy.

Effects of phosphonium-based ionic liquids on phospholipid membranes studied by small-angle X-ray scattering.

PubMed

Kontro, Inkeri; Svedström, Kirsi; Duša, Filip; Ahvenainen, Patrik; Ruokonen, Suvi-Katriina; Witos, Joanna; Wiedmer, Susanne K

2016-12-01

The effects of ionic liquids on model phospholipid membranes were studied by small-angle X-ray scattering, dynamic light scattering (DLS) and zeta potential measurements. Multilamellar 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes and large unilamellar vesicles composed of l-α-phosphatidylcholine (eggPC) and l-α-phosphatidylglycerol (eggPG) (80:20mol%) or eggPC, eggPG, and cholesterol (60:20:20mol%) were used as biomimicking membrane models. The effects of the phosphonium-based ionic liquids: tributylmethylphosphonium acetate, trioctylmethylphosphonium acetate, tributyl(tetradecyl)-phosphonium acetate, and tributyl(tetradecyl)-phosphonium chloride, were compared to those of 1-ethyl-3-methyl-imidazolium acetate. With multilamellar vesicles, the ionic liquids that did not disrupt liposomes decreased the lamellar spacing as a function of concentration. The magnitude of the effect depended on concentration for all studied ionic liquids. Using large unilamellar vesicles, first a slight decrease in the vesicle size, then aggregation of vesicles was observed by DLS for increasing ionic liquid concentrations. At concentrations just below those that caused aggregation of liposomes, large unilamellar vesicles were coated by ionic liquid cations, evidenced by a change in their zeta potential. The ability of phosphonium-based ionic liquids to affect liposomes is related to the length of the hydrocarbon chains in the cation. Generally, the ability of ionic liquids to disrupt liposomes goes hand in hand with inducing disorder in the phospholipid membrane. However, trioctylmethylphosphonium acetate selectively extracted and induced a well-ordered lamellar structure in phospholipids from disrupted cholesterol-containing large unilamellar vesicles. This kind of effect was not seen with any other combination of ionic liquids and liposomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Inhibition of ovarian development by methyl farnesoate in the tadpole shrimp, Triops longicaudatus.

PubMed

Tsukimura, B; Nelson, W K; Linder, C J

2006-06-01

Methyl farnesoate (MF), a putative crustacean hormone, is the immediate precursor of insect juvenile hormone III (JHIII) in the biosynthetic pathway. We examined whether MF, shown to inhibit adult metamorphosis in several crustacean species, is a juvenilizing factor in the tadpole shrimp, Triops longicaudatus. Oocyte production was chosen as a parameter for measuring reproductive development. MF was administered to juveniles by ingestion via biological vector (Artemia nauplii), MF-coated food pellets, and MF liposome food pellets. Artemia were incubated in 30 microl of 5 microg/ml MF. The MF-coated and MF liposome pellets were prepared with MF concentrations ranging between 0.1 microg/g and 10 microg/g MF by weight. Groups of tadpole shrimp were treated with these vectors from the time of hatching for 5 or 10 days in laboratory and field studies. The treatment groups of all the MF vectors showed reductions in oocyte production. Lower concentrations of MF (0.75 microg/g-3.8 microg/g MF) appeared to have a physiological effect on fecundity, but higher concentrations (10 microg/g MF) reduced somatic growth. MF-coated pellets (1 microg/g MF) administered to adults (after 5 days) caused no difference in oocyte production. The observed reductions of fecundity and the disparity of results between MF treatment on juveniles and adults suggest that MF may regulate ovarian development.

Impact of pectin esterification on the antimicrobial activity of nisin-loaded pectin particles.

PubMed

Krivorotova, Tatjana; Staneviciene, Ramune; Luksa, Juliana; Serviene, Elena; Sereikaite, Jolanta

2017-01-01

The relationship between pectin structure and the antimicrobial activity of nisin-loaded pectin particles was examined. The antimicrobial activity of five different nisin-loaded pectin particles, i.e., nisin-loaded high methoxyl pectin, low methoxyl pectin, pectic acid, dodecyl pectin with 5.4 and 25% degree of substitution were tested in the pH range of 4.0-7.0 by agar-diffusion assay and agar plate count methods. It was found that the degree of esterification of carboxyl group of galacturonic acid in pectin molecule is important for the antimicrobial activity of nisin-loaded pectin particles. Nisin-loaded particles prepared using pectic acid or the pectin with low degree of esterification exhibit higher antimicrobial activity than nisin-loaded high methoxyl pectin particles. Pectins with free carboxyl groups or of low degree of esterification are the most suitable for particles preparation. Moreover, nisin-loaded pectin particles were active at close to neutral or neutral pH values. Therefore, they could be effectively applied for food preservation. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:245-251, 2017. © 2016 American Institute of Chemical Engineers.

Structural characteristics of pumpkin pectin extracted by microwave heating.

PubMed

Yoo, Sang-Ho; Lee, Byeong-Hoo; Lee, Heungsook; Lee, Suyong; Bae, In Young; Lee, Hyeon Gyu; Fishman, Marshall L; Chau, Hoa K; Savary, Brett J; Hotchkiss, Arland T

2012-11-01

To improve extraction yield of pumpkin pectin, microwave heating was adopted in this study. Using hot acid extraction, pumpkin pectin yield decreased from 5.7% to 1.0% as pH increased from pH 1.0 to 2.0. At pH 2.5, no pectin was recovered from pumpkin flesh powder. After a pretreatment at pH 1.0 and 25 °C for 1 h, pumpkin powder was microwave-extracted at 120 °C for 3 min resulting in 10.5% of pectin yield. However, premicrowave treatment at 60 °C for 20 min did not improve extraction yield. When microwave heating at 80 °C for 10 min was applied after premicrowave treatment, final pectin yield increased to 11.3%. When pH was adjusted to 2.0, the yield dropped to 7.7% under the same extraction conditions. Molecular shape and properties as well as chemical composition of pumpkin pectin were significantly affected depending on extraction methods. Galacturonic acid content (51% to 58%) of pumpkin pectin was lower than that detected in commercial acid-extracted citrus pectin, while higher content of neutral sugars and acetyl esters existed in pumpkin pectin structure. Molecular weight (M(w) ) and intrinsic viscosity (η(w) ) determined for microwave-extracted pumpkin pectins were substantially lower than acid-extracted pectin, whereas polydispersity was greater. However, microwave-extracted pectin at pH 2.0 had more than 5 times greater M(w) than did the pectin extracted at pH 1.0. The η(w) of microwave-extracted pectin produced at pH 2.0 was almost twice that of other microwave-extracted pectins, which were comparable to that of acid-extracted pectin. These results indicate that extraction yield of pumpkin pectin would be improved by microwave extraction and different pectin structure and properties can be obtained compared to acid extraction. Pumpkin is a promising alternative source for pectin material. Pumpkin pectin has a unique chemical structure and physical properties, presumably providing different functional properties compared to conventional commercial pectin sources. Depending on the conditions to produce pumpkin pectin, diverse molecular structures can be obtained and utilized in various food applications. © 2012 Institute of Food Technologists®

Liposomes as lubricants: beyond drug delivery.

PubMed

Goldberg, Ronit; Klein, Jacob

2012-05-01

In this paper we review recent work (Goldberg et al., 2011a,b) on a new use for phosphatidylcholine liposomes: as ultra-efficient boundary lubricants at up to the highest physiological pressures. Using a surface force balance, we have measured the normal and shear interactions as a function of surface separation between layers of hydrogenated soy phophatidylcholine (HSPC) small unilamellar vesicles (SUVs) adsorbed from dispersion, at both pure water and physiologically high salt concentrations of 0.15 M NaNO(3). Cryo-Scanning Electron Microscopy shows each surface to be coated by a close-packed HSPC-SUV layer with an over-layer of liposomes on top. The shear forces reveal strikingly low friction coefficients down to 2×10(-5) in pure water system or 6×10(-4) in the 150 mM salt system, up to contact pressures of at least 12 MPa (pure water) or 6 MPa (high salt), comparable with those in the major joints. This low friction is attributed to the hydration lubrication mechanism arising from rubbing of the highly hydrated phosphocholine-headgroup layers exposed at the outer surface of each liposome, and provides support for the conjecture that phospholipids may play a significant role in biological lubrication. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Edible films from pectin: Physical-mechanical and antimicrobial properties - A Review

USDA-ARS?s Scientific Manuscript database

Pectin is one of the main components of the plant cell wall and chemically, pectin is constituted by poly a1–4-galacturonic acids. According to its degree of esterification with methanol, pectin can be classified as high methoxyl pectin or low methoxyl pectin. In food industry, pectin is listed as g...

Engineering Remotely Triggered Liposomes to Target Triple Negative Breast Cancer

PubMed Central

Sneider, Alexandra; Jadia, Rahul; Piel, Brandon; VanDyke, Derek; Tsiros, Christopher; Rai, Prakash

2017-01-01

Triple Negative Breast Cancer (TNBC) continues to present a challenge in the clinic, as there is still no approved targeted therapy. TNBC is the worst sub-type of breast cancer in terms of prognosis and exhibits a deficiency in estrogen, progesterone, and human epidermal growth factor 2 (HER2) receptors. One possible option for the treatment of TNBC is chemotherapy. The issue with many chemotherapy drugs is that their effectiveness is diminished due to poor water solubility, and the method of administration directly or with a co-solvent intravenously can lead to an increase in toxicity. The issues of drug solubility can be avoided by using liposomes as a drug delivery carrier. Liposomes are engineered, biological nanoconstructs that possess the ability to encapsulate both hydrophobic and hydrophilic drugs and have been clinically approved to treat cancer. Specific targeting of cancer cell receptors through the use of ligands conjugated to the surface of drug-loaded liposomes could lessen damage to normal, healthy tissue. This study focuses on polyethylene glycol (PEG)-coated, folate conjugated, benzoporphyrin derivative (BPD)-loaded liposomes for treatment via photodynamic therapy (PDT). The folate receptor is over expressed on TNBC cells so these liposomes are targeted for greater uptake into cancer cells. PDT involves remotely irradiating light at 690 nm to trigger BPD, a hydrophobic photosensitive drug, to form reactive oxygen species that cause tumor cell death. BPD also displays a fluorescence signal when excited by light making it possible to image the fluorescence prior to PDT and for theranostics. In this study, free BPD, non-targeted and folate-targeted PEGylated BPD-loaded liposomes were introduced to a metastatic breast cancer cell line (MDA-MB-231) in vitro. The liposomes were reproducibly synthesized and characterized for size, polydispersity index (PDI), zeta potential, stability, and BPD release kinetics. Folate competition tests, fluorescence confocal imaging, and MTT assay were used to observe and quantify targeting effectiveness. The toxicity of BPD before and after PDT in monolayer and 3D in vitro cultures with TNBC cells was observed. This study may contribute to a novel nanoparticle-mediated approach to target TNBC using PDT. PMID:28174679

Thiolated pectin-doxorubicin conjugates: Synthesis, characterization and anticancer activity studies.

PubMed

Cheewatanakornkool, Kamonrak; Niratisai, Sathit; Manchun, Somkamol; Dass, Crispin R; Sriamornsak, Pornsak

2017-10-15

In this paper, pectin was cross-linked by a coupling reaction with either thioglycolic acid or cystamine dihydrochloride to form thiolated pectins. The thiolated pectins were then coupled with doxorubicin (DOX) derivative to obtain thiolated pectin-DOX conjugates by two different methods, disulfide bond formation and disulfide bond exchange. The disulfide bond exchange method provided a simple, fast, and efficient approach for synthesis of thiolated pectin-DOX conjugates, compared to the disulfide bond formation. Characteristics, physicochemical properties, and morphology of thiolated pectins and thiolated pectin-DOX conjugates were determined. DOX content in thiolated pectin-DOX conjugates using low methoxy pectin was found to be higher than that using high methoxy pectin. The in vitro anticancer activity of thiolated pectin-DOX conjugates was significantly higher than that of free DOX, in mouse colon carcinoma and human bone osteosarcoma cells, but insignificantly different from that of free DOX, in human prostate cancer cells. Due to their promising anticancer activity in mouse colon carcinoma cells, the thiolated pectin-DOX conjugates might be suitable for building drug platform for colorectal cancer-targeted delivery of DOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cholesterol-lowering properties of different pectin types in mildly hyper-cholesterolemic men and women.

PubMed

Brouns, F; Theuwissen, E; Adam, A; Bell, M; Berger, A; Mensink, R P

2012-05-01

Viscous fibers typically reduce total cholesterol (TC) by 3-7% in humans. The cholesterol-lowering properties of the viscous fiber pectin may depend on its physico-chemical properties (viscosity, molecular weight (MW) and degree of esterification (DE)), but these are not typically described in publications, nor required by European Food Safety Authority (EFSA) with respect to its generic pectin cholesterol-lowering claim. Here, different sources and types of well-characterized pectin were evaluated in humans. Cross-over studies were completed in mildly hyper-cholesterolemic persons receiving either 15 g/day pectin or cellulose with food for 4 weeks. Relative low-density lipoprotein (LDL) cholesterol (LDL-C) lowering was as follows: citrus pectin DE-70=apple pectin DE-70 (7-10% reduction versus control)>apple pectin DE-35=citrus pectin DE-35>OPF (orange pulp fiber) DE-70 and low-MW pectin DE-70>citrus DE-0. In a subsequent 3-week trial with 6 g/day pectin, citrus DE-70 and high MW pectin DE-70 reduced LDL-C 6-7% versus control (without changes in TC). In both studies, high DE and high MW were important for cholesterol lowering. Source may also be important as citrus and apple DE-70 pectin were more effective than OPF DE-70 pectin. Pectin did not affect inflammatory markers high-sensitivity C-reactive protein (hsCRP) nor plasma homocysteine. Pectin source and type (DE and MW) affect cholesterol lowering. The EFSA pectin cholesterol-lowering claim should require a minimum level of characterization, including DE and MW.

Textural properties of gelling system of low-methoxy pectins produced by demethoxylating reaction of pectin methyl esterase.

PubMed

Kim, Y; Yoo, Y-H; Kim, K-O; Park, J-B; Yoo, S-H

2008-06-01

After deesterification of commercial pectins with a pectin methyl esterase (PME), their gelling properties were characterized using instrumental texture analysis. The final degree of esterification (DE) of the high- and low-methoxy pectins reached approximately 6% after the PME treatment, while deesterification of low-methoxy amidated pectin stopped at 18% DE. Furthermore, DE of high-methoxy pectin was tailored to be 40%, which is equivalent to the DE of commercial low-methoxy pectin. As a result, significant changes in molecular weight (Mw) distribution were observed in the PME-treated pectins. The texture profile analysis showed that PME modification drastically increased hardness, gumminess, and chewiness, while decreasing cohesiveness and adhesiveness of the pectin gels (P < 0.05). The pectin gel with relatively high peak molecular weight (Mp, 3.5 x 10(5)) and low DE (6), which was produced from high-methoxy pectin, exhibited the greatest hardness, gumminess, chewiness, and resilience. The hardness of low-methoxy amidated pectin increased over 300% after PME deesterification, suggesting that the effects of amide substitution could be reinforced when DE is even lower. The partial least square regression analysis indicated that the Mw and DE of the pectin molecule are the most crucial factors for hardness, chewiness, gumminess, and resilience of gel matrix.

pH-sensitive stearoyl-PEG-poly(methacryloyl sulfadimethoxine) decorated liposomes for the delivery of gemcitabine to cancer cells.

PubMed

Bersani, Sara; Vila-Caballer, Marian; Brazzale, Chiara; Barattin, Michela; Salmaso, Stefano

2014-11-01

Novel, acid-sensitive liposomes that respond to physiopathological pH for tumour targeting applications were obtained by surface decoration with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)] (mPEG-DSPE) and stearoyl-poly(ethylene glycol)-poly(methacryloyl sulfadimethoxine) copolymer (stearoyl-PEG-polySDM). The pH-sensitive stearoyl-PEG-polySDM copolymer contained an average of seven methacryloyl sulfadimethoxines per molecule and was found to possess an apparent pKa of 7.2. Preliminary cloud point studies showed that the hydrophilic/hydrophobic copolymer conversion occurred at pH 7.0. The copolymer was soluble above pH 7.0 and underwent aggregation at lower pH. Liposome formulations were prepared with 0.2:0.6:100, 0.5:1.5:100 and 1:3:100 mPEG-DSPE/stearoyl-PEG-polySDM/lipids molar ratios. All of the liposome formulations were stable at pH 7.4, even in the presence of foetal bovine serum, but they underwent rapid size increase at pH 6.5. TEM analysis showed that, at pH 6.5, the formulations coated with a stearoyl-PEG-polySDM/lipids molar ratio greater than 1:100 underwent aggregation. At pH 7.4, the liposomes showed negative zeta potential that significantly decreased after incubation at pH 6.5. Cell-culture studies indicated that the liposomes were not toxic up to 10mg/mL. Fluorescence spectroscopy, cytofluorimetry and confocal microscopy showed that at pH 6.5, the incubation of MCF-7 tumour cells with fluorescein-labelled 1:3:100 mPEG-DSPE/stearoyl-PEG-polySDM/lipids molar ratio liposomes resulted in time-dependent cell association, while at pH 7.4 the cell interaction was significantly lower. The same pH-responsive liposome formulation loaded with gemcitabine (98.2±4.7nmol gemcitabine/lipid μmol loading capacity) was stable at pH 7.4 for several hours, while at pH 6.5 it rapidly aggregated. At pH 6.5, these liposomes displayed higher cytotoxicity than at pH 7.4 or compared to non-responsive control liposomes at both incubation pH. Notably, treatment with free gemcitabine did not yield cytotoxic effects, indicating that the carrier can efficiently deliver the anticancer drug to the cytosolic compartment. Copyright © 2014 Elsevier B.V. All rights reserved.

Time-evolution of in vivo protein corona onto blood-circulating PEGylated liposomal doxorubicin (DOXIL) nanoparticles.

PubMed

Hadjidemetriou, Marilena; Al-Ahmady, Zahraa; Kostarelos, Kostas

2016-04-07

Nanoparticles (NPs) are instantly modified once injected in the bloodstream because of their interaction with the blood components. The spontaneous coating of NPs by proteins, once in contact with biological fluids, has been termed the 'protein corona' and it is considered to be a determinant factor for the pharmacological, toxicological and therapeutic profile of NPs. Protein exposure time is thought to greatly influence the composition of protein corona, however the dynamics of protein interactions under realistic, in vivo conditions remain unexplored. The aim of this study was to quantitatively and qualitatively investigate the time evolution of in vivo protein corona, formed onto blood circulating, clinically used, PEGylated liposomal doxorubicin. Protein adsorption profiles were determined 10 min, 1 h and 3 h post-injection of liposomes into CD-1 mice. The results demonstrated that a complex protein corona was formed as early as 10 min post-injection. Even though the total amount of protein adsorbed did not significantly change over time, the fluctuation of protein abundances observed indicated highly dynamic protein binding kinetics.

The Role of Pectin in Pb Binding by Carrot Peel Biosorbents: Isoterm Adsorption Study

NASA Astrophysics Data System (ADS)

Hastuti, B.; Totiana, F.; Winiasih, R.

2018-04-01

Cheaply and abundantly biosorption available materials such as carrot peels can be a cost-efficient method for removing heavy metals from wastewater. To investigate the role pectin plays in metal binding by carrot peels, commerce pectin was compared. FTIR spectra confirmed the presence of carboxyl and hydroxyl groups in commerce pectin and carrot pectin. Isoterm experiments showed that all materials could remove Pb (II) ion. All of materials binding Pb (II) follow Freundlich models adsorption. The commerce pectin bindsPb (II) by involving energy 16.6 KJ/mole whereas pectin from carrot peel involves energy 21.09 KJ/mole. It indicates that commerce pectin binds the Pb (II) by physics adsorption whereas pectin from carrot peel by physics and chemical adsorption.

Pectin methyl esterase treatment on high-methoxy pectin for making fruit jam with reduced sugar content.

PubMed

Wang, Yuh-Tai; Lien, Ling-Lan; Chang, Ya-Chu; Wu, James Swi-Bea

2013-01-01

Pectin methyl esterase (PME) has been postulated to catalyse the transacylation reaction between pectin molecules. The present study aimed to prove the occurrence of this reaction. The feasibility of applying PME-catalysed transacylation between high-methoxy pectin molecules in making fruit jam with reduced sugar content was also investigated. PME treatment increased the turbidity and particle size in pectin solution and the molecular weight of pectin, while it decreased the number of methoxy ester linkages and the intensity of the CH₃ absorption peak in the Fourier transform infrared spectrum without changes in the number of total ester linkages in pectin molecules. These findings support the occurrence of PME-catalysed transacylation between pectin molecules. Higher values of hardness, gumminess and chewiness were found in a jam containing PME-treated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) as compared with either a jam containing untreated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) or strawberry jam containing pectin (10 g L⁻¹) from the fruit and sugar (650 g L⁻¹). The demand for sugar in jam making can be greatly reduced by the use of PME-treated high-methoxy pectin. Copyright © 2012 Society of Chemical Industry.

Pectin-modifying enzymes and pectin-derived materials: applications and impacts.

PubMed

Bonnin, Estelle; Garnier, Catherine; Ralet, Marie-Christine

2014-01-01

Pectins are complex branched polysaccharides present in primary cell walls. As a distinctive feature, they contain high amount of partly methyl-esterified galacturonic acid and low amount of rhamnose and carry arabinose and galactose as major neutral sugars. Due to their structural complexity, they are modifiable by many different enzymes, including hydrolases, lyases, and esterases. Their peculiar structure is the origin of their physicochemical properties. Among others, their remarkable gelling properties make them a key additive for food industries. Pectin-degrading enzymes and -modifying enzymes may be used in a wide variety of applications to modulate pectin properties or produce pectin derivatives and oligosaccharides with functional as well as nutritional interests. This paper reviews the scientific information available on pectin structure, pectin-modifying enzymes, and the use of enzymes to produce pectin with controlled structure or pectin-derived oligosaccharides, with functional or nutritional interesting properties.

Pectin anaphylaxis and possible association with cashew allergy.

PubMed

Ferdman, Ronald M; Ong, Peck Y; Church, Joseph A

2006-12-01

Inhalation of pectin has been identified as a cause of occupational asthma. However, allergic reactions to orally ingested pectin have not been reported. To describe a child with pectin-induced food anaphylaxis and to discuss its possible relationship to cashew allergy. A 3 1/2-year-old boy developed anaphylaxis once after eating cashews and later after eating a pectin-containing fruit "smoothie." He also has a history of generalized pruritus after eating grapefruit. Skin tests or radioallergosorbent tests (RASTs) were performed to pectin and other suspected food allergens. The child had a positive skin prick test reaction to pectin and a high RAST reaction to cashew and pistachio. He had a low-level positive RAST reaction to grapefruit. Results of allergy tests for the other potential food allergens were negative. The pectin in the smoothie was confirmed to be of citrus origin. Review of previous case reports of pectin-induced occupational asthma revealed several patients with allergies to and cross-reactivity with cashew. Ingestion, not only inhalation, of pectin can cause hypersensitivity reactions. Cashew, and possibly pistachio, allergy may be associated with pectin allergy, and the possibility of pectin allergy should be considered in cashew- or pistachio-allergic patients who have unexplained allergic reactions.

Environmentally friendly preparation of pectins from agricultural byproducts and their structural/rheological characterization.

PubMed

Min, Bockki; Lim, Jongbin; Ko, Sanghoon; Lee, Kwang-Geun; Lee, Sung Ho; Lee, Suyong

2011-02-01

Apple pomace which is the main waste of fruit juice industry was utilized to extract pectins in an environmentally friendly way, which was then compared with chemically-extracted pectins. The water-based extraction with combined physical and enzymatic treatments produced pectins with 693.2 mg g(-1) galacturonic acid and 4.6% yield, which were less than those of chemically-extracted pectins. Chemically-extracted pectins exhibited lower degree of esterification (58%) than the pectin samples obtained by physical/enzymatic treatments (69%), which were also confirmed by FT-IR analysis. When subjected to steady-shear rheological conditions, both pectin solutions were shown to have shear-thinning properties. However, decreased viscosity was observed in the pectins extracted by combined physical/enzymatic methods which could be mainly attributed to the presence of more methyl esters, thus limiting polymer chain interactions. Moreover, the pectins which were extracted by combined physical/enzymatic treatments, showed less elastic properties under high shear rate conditions, compared to the chemically-extracted pectins. Copyright © 2010 Elsevier Ltd. All rights reserved.

Preparation of ultra-fine powders from polysaccharide-coated solid lipid nanoparticles and nanostructured lipid carriers by innovative nano spray drying technology.

PubMed

Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

2016-09-10

In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20-30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication, characterization and application of pectin degrading Fe3O4-SiO2 nanobiocatalyst.

PubMed

Seenuvasan, Muthulingam; Malar, Carlin Geor; Preethi, Sridhar; Balaji, Nagarajan; Iyyappan, Jeyaraj; Kumar, Madhava Anil; Kumar, Kannaiyan Sathish

2013-05-01

The covalent binding of pectinase onto amino functionalized silica-coated magnetic nanoparticles (CSMNPs) through glutaraldehyde activation was investigated for nanobiocatalyst fabrication. The average particle size and morphology of the nanoparticles were characterized using transmission electron microscopy (TEM). The statistical analysis for TEM image suggests that the coating and binding process did not cause any significant change in size of MNPs. The morphological and phase change of the magnetic nanoparticles (MNPs) after various coatings and immobilization were characterized by X-ray diffraction (XRD) studies. The various surface modifications and pectinase binding onto nanoparticles were confirmed by Fourier transform infrared (FT-IR) spectroscopy. The maximum activity of immobilized pectinase was obtained at its weight ratio of 19.0×10(-3) mg bound pectinase/mg CSMNPs. The pH, temperature, reusability, storage ability and kinetic studies were established to monitor their improved stability and activity of the fabricated nanobiocatalyst. Furthermore, the application was extended in the clarification of Malus domestica juice. Copyright © 2013 Elsevier B.V. All rights reserved.

Dissecting Seed Mucilage Adherence Mediated by FEI2 and SOS5

PubMed Central

Griffiths, Jonathan S.; Crepeau, Marie-Jeanne; Ralet, Marie-Christine; Seifert, Georg J.; North, Helen M.

2016-01-01

The plant cell wall is held together by the interactions between four major components: cellulose, pectin, hemicellulose, and proteins. Mucilage is a powerful model system to study the interactions between these components as it is formed of polysaccharides that are deposited in the apoplast of seed coat epidermal cells during seed development. When seeds are hydrated, these polysaccharides expand rapidly out of the apoplastic pocket, and form an adherent halo of mucilage around the seed. In Arabidopsis, mutations in multiple genes have similar loss of mucilage adherence phenotypes including CELLULOSE SYNTHASE 5 (CESA5)/MUCILAGE-MODIFIED 3 (MUM3), MUM5/MUCI21, SALT-OVERLY SENSITIVE 5 (SOS5), and FEI2. Here, we examine the interactions between these factors to better understand how they participate to control mucilage adherence. Double mutant phenotypes indicated that MUM5 and CESA5 function in a common mechanism that adheres pectin to the seed through the biosynthesis of cellulose and xylan, whereas SOS5 and FEI2, encoding a fasciclin-like arabinogalactan protein or a receptor-like kinase, respectively, function through an independent pathway. Cytological analyses of mucilage indicates that heteromannans are associated with cellulose, and not in the pathway involving SOS5 or FEI2. A SOS5 fluorescent protein fusion (SOS5-mCITRINE) was localized throughout the mucilage pocket, consistent with a structural role in pectin adhesion. The relationship between SOS5 and FEI2 mediated mucilage adherence was examined in more detail and while sos5 and fei2 mutants show similar phenotypes, key differences in the macromolecular characteristics and amounts of mucilage polymers were observed. FEI2 thus appears to have additional, as well as overlapping functions, with SOS5. Given that FEI2 is required for SOS5 function, we propose that FEI2 serves to localize SOS5 at the plasma membrane where it establishes interactions with mucilage polysaccharides, notably pectins, required for mucilage adherence prior to SOS5 being released into the apoplast. PMID:27524986

Delayed post-harvest ripening-associated changes in Manilkara zapota L. var. Kalipatti with composite edible coating.

PubMed

Vishwasrao, Chandrahas; Ananthanarayan, Laxmi

2017-01-01

There has been limited research on extending the shelf-life of sapota (Manilkara zapota L. var. Kalipatti) fruit. An edible coating made up of methyl cellulose (MC) and palm oil (PO) was applied to study the extension in shelf-life. Changes in physical and chemical properties of fruit were studied along with peroxidase (POD), polyphenol oxidase (PPO) and pectin methylesterase (PME) activities during post-harvest ripening of sapota. The fruits coated with 15 g L -1 MC and 11.25 g L -1 PO showed significant (P < 0.05) delay in physiological weight loss, decrease in fruit firmness losses as well as slower fruit darkening. The coating on the fruits resulted in better retention of ascorbic acid, delayed the loss of total phenolic content, and delayed the increase in total soluble solids and total reducing sugars as compared to control fruits. The coating either delayed or reduced the enzyme activities of POD, PPO and PME of the fruit. The results suggest that edible coating made up of MC-PO has potential to maintain the quality of sapota fruit. The edible coating extended the shelf-life of sapota fruit by 3 days preserving fruit quality up to 7 days at 24 ± 1 °C and 65 ± 5 %RH. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Structurally modified pectin for targeted lipid antioxidant capacity in linseed/sunflower oil-in-water emulsions.

PubMed

Celus, Miete; Salvia-Trujillo, Laura; Kyomugasho, Clare; Maes, Ine; Van Loey, Ann M; Grauwet, Tara; Hendrickx, Marc E

2018-02-15

The present work explored the lipid antioxidant capacity of citrus pectin addition to 5%(w/v) linseed/sunflower oil emulsions stabilized with 0.5%(w/v) Tween 80, as affected by pectin molecular characteristics. The peroxide formation in the emulsions, containing tailored pectin structures, was studied during two weeks of storage at 35°C. Low demethylesterified pectin (≤33%) exhibited a higher antioxidant capacity than high demethylesterified pectin (≥58%), probably due to its higher chelating capacity of pro-oxidative metal ions (Fe 2+ ), whereas the distribution pattern of methylesters along the pectin chain only slightly affected the antioxidant capacity. Nevertheless, pectin addition to the emulsions caused emulsion destabilization probably due to depletion or bridging effect, independent of the pectin structural characteristics. These results evidence the potential of structurally modified citrus pectin as a natural antioxidant in emulsions. However, optimal conditions for emulsion stability should be carefully selected. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soft poly(2-chloroaniline)/pectin hydrogel and its electromechanical properties.

PubMed

Kongkaew, Wanar; Sangwan, Watchara; Lerdwijitjarud, Wanchai; Sirivat, Anuvat

2018-01-01

Pectin hydrogels were successfully fabricated with various physical crosslinkers and concentrations for soft actuator applications. A small amount of synthesized P2ClAn was added as a dispersed phase into the pectin matrix. The electromechanical properties of the pectin hydrogels and blends were investigated under the effects of electric field strength, ionic crosslinker type and concentration, and P2ClAn concentration. The electromechanical properties of the pectin hydrogel as crosslinked by Fe 2+ were superior to other pectin hydrogels. The pristine pectin hydrogel and the P2ClAn/Pectin hydrogel blended with 0.10%v/v P2ClAn provided the high storage modulus sensitivity values of 8.61 and 14.01, respectively, under the electric field strength of 800 V/mm. The P2ClAn/Pectin hydrogel blend responded to the electric field with higher dielectrophoretic forces, but lower deflections relative to the pristine pectin hydrogel due to the additional P2ClAn polarization and the latter lower rigidity.

Lipid-Coated Gold Nanoparticles and FRET Allow Sensitive Monitoring of Liposome Clustering Mediated by the Synaptotagmin-7 C2A Domain.

PubMed

Hamilton, Desmond J; Coffman, Matthew D; Knight, Jefferson D; Reed, Scott M

2017-09-12

Synaptotagmin (Syt) family proteins contain tandem C2 domains, C2A and C2B, which insert into anionic membranes in response to increased cytosolic Ca 2+ concentration and facilitate exocytosis in neuronal and endocrine cells. The C2A domain from Syt7 binds lipid membranes much more tightly than the corresponding domain from Syt1, but the implications of this difference for protein function are not yet clear. In particular, the ability of the isolated Syt7 C2A domain to initiate membrane apposition and/or aggregation has been previously unexplored. Here, we demonstrate that Syt7 C2A induces apposition and aggregation of liposomes using Förster resonance energy transfer (FRET) assays, dynamic light scattering, and spectroscopic techniques involving lipid-coated gold nanoparticles (LCAuNPs). Protein-membrane binding, membrane apposition, and macroscopic aggregation are three separate phenomena with distinct Ca 2+ requirements: the threshold Ca 2+ concentration for membrane binding is lowest, followed by apposition and aggregation. However, aggregation is highly sensitive to protein concentration and can occur even at submicromolar Syt7 C2A; thus, highly sensitive assays are needed for measuring apposition without complications arising from aggregation. Notably, the localized surface plasmon resonance of the LCAuNP is sensitive to ≤10 nM Syt7 C2A concentrations. Furthermore, when the LCAuNPs were added into a FRET-based liposome apposition assay, the resultant energy transfer increased; possible explanations are discussed. Overall, LCAuNP-based methods allow for highly sensitive detection of protein-induced membrane apposition under conditions that miminize large-scale aggregation.

Tissue specific localization of pectin-Ca²⁺ cross-linkages and pectin methyl-esterification during fruit ripening in tomato (Solanum lycopersicum).

PubMed

Hyodo, Hiromi; Terao, Azusa; Furukawa, Jun; Sakamoto, Naoya; Yurimoto, Hisayoshi; Satoh, Shinobu; Iwai, Hiroaki

2013-01-01

Fruit ripening is one of the developmental processes accompanying seed development. The tomato is a well-known model for studying fruit ripening and development, and the disassembly of primary cell walls and the middle lamella, such as through pectin de-methylesterified by pectin methylesterase (PE) and depolymerization by polygalacturonase (PG), is generally accepted to be one of the major changes that occur during ripening. Although many reports of the changes in pectin during tomato fruit ripening are focused on the relation to softening of the pericarp or the Blossom-end rot by calcium (Ca²⁺) deficiency disorder, the changes in pectin structure and localization in each tissues during tomato fruit ripening is not well known. In this study, to elucidate the tissue-specific role of pectin during fruit development and ripening, we examined gene expression, the enzymatic activities involved in pectin synthesis and depolymerisation in fruit using biochemical and immunohistochemical analyses, and uronic acids and calcium (Ca)-bound pectin were determined by secondary ion-microprobe mass spectrometry. These results show that changes in pectin properties during fruit development and ripening have tissue-specific patterns. In particular, differential control of pectin methyl-esterification occurs in each tissue. Variations in the cell walls of the pericarp are quite different from that of locular tissues. The Ca-binding pectin and hairy pectin in skin cell layers are important for intercellular and tissue-tissue adhesion. Maintenance of the globular form and softening of tomato fruit may be regulated by the arrangement of pectin structures in each tissue.

Foaming and emulsifying properties of pectin isolated from different plant materials

NASA Astrophysics Data System (ADS)

Yancheva, Nikoleta; Markova, Daniela; Murdzheva, Dilyana; Vasileva, Ivelina; Slavov, Anton

2016-03-01

The foaming and emulsifying properties of pectins obtained from waste rose petals, citrus pressings, grapefruit peels and celery were studied. It was found that the highest foaming capacity showed pectin derived from celery. The effect of pectin concentration on the foaming capacity of pectin solutions was investigated. For all the investigated pectins increasing the concentration led to increase of the foaming capacity. Emulsifying activity and emulsion stability of model emulsion systems (50 % oil phase) with 0.6 % pectic solutions were determined. The highest emulsifying activity and stability showed pectin isolated by dilute acid extraction from waste rose petals.

Pectin gel vehicles for controlled fragrance delivery.

PubMed

Liu, LinShu; Chen, Guoying; Fishman, Marshall L; Hicks, Kevin B

2005-01-01

Using citronellal as a model compound, pectin gels formulations were evaluated for the controlled fragrance release by kinetic and static methods. The pectins with higher degrees of esterification induced a stronger molecular association with the nonpolar fragrance. This resulted in a prolonged duration of fragrance release and the limitation of fragrance adsorption to the receptor skin layers. The increase in pectin concentrations suppressed the fragrance release by a diffusion mechanism. Blocking the carboxyl groups of pectin with calcium ions reduces the hydrophilicity of pectin and provides physical barriers for citronellal diffusion. The pectin/calcium microparticles are promising materials for controlled fragrance release.

Effect of temperature and high pressure on the activity and mode of action of fungal pectin methyl esterase.

PubMed

Duvetter, Thomas; Fraeye, Ilse; Sila, Daniel N; Verlent, Isabel; Smout, Chantal; Clynen, Elke; Schoofs, Liliane; Schols, Henk; Hendrickx, Marc; Van Loey, Ann

2006-01-01

Pectin was de-esterified with purified recombinant Aspergillus aculeatus pectin methyl esterase (PME) during isothermal-isobaric treatments. By measuring the release of methanol as a function of treatment time, the rate of enzymatic pectin conversion was determined. Elevated temperature and pressure were found to stimulate PME activity. The highest rate of PME-catalyzed pectin de-esterification was obtained when combining pressures in the range 200-300 MPa with temperatures in the range 50-55 degrees C. The mode of pectin de-esterification was investigated by characterizing the pectin reaction products by enzymatic fingerprinting. No significant effect of increasing pressure (300 MPa) and/or temperature (50 degrees C) on the mode of pectin conversion was detected.

Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

PubMed

Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Cortés, Pilar; Maspoch, Daniel; Llagostera, Montserrat

2015-07-01

Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Liposome-Encapsulated Bacteriophages for Enhanced Oral Phage Therapy against Salmonella spp.

PubMed Central

Colom, Joan; Cano-Sarabia, Mary; Otero, Jennifer; Cortés, Pilar

2015-01-01

Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units. The liposome coating also improved the retention of bacteriophages in the chicken intestinal tract. When cocktails of the encapsulated and nonencapsulated phages were administered to broilers, after 72 h the encapsulated phages were detected in 38.1% of the animals, whereas the nonencapsulated phages were present in only 9.5%. The difference was significant. In addition, in an in vitro experiment, the cecal contents of broilers promoted the release of the phages from the liposomes. In broilers experimentally infected with Salmonella, the daily administration of the two cocktails for 6 days postinfection conferred similar levels of protection against Salmonella colonization. However, once treatment was stopped, protection by the nonencapsulated phages disappeared, whereas that provided by the encapsulated phages persisted for at least 1 week, showing the enhanced efficacy of the encapsulated phages in protecting poultry against Salmonella over time. The methodology described here allows the liposome encapsulation of phages of different morphologies. The preparations can be stored for at least 3 months at 4°C and could be added to the drinking water and feed of animals. PMID:25956778

Optimization of pectin extraction and antioxidant activities from Jerusalem artichoke

NASA Astrophysics Data System (ADS)

Liu, Shengyi; Shi, Xuejie; Xu, Lanlan; Yi, Yuetao

2016-03-01

Jerusalem artichoke is an economic crop widely planted in saline-alkaline soil. The use of Jerusalem artichoke is of great significance. In this study, the response surface method was employed to optimize the effects of processing variables (extraction temperature, pH, extraction time, and liquid-to-solid ratio) on the yield of Jerusalem artichoke pectin. Under the optimal extraction conditions: pH 1.52, 63.62 min, 100°C and a liquid-to-solid ratio of 44.4 mL/g, the maximum pectin yield was predicted to be 18.76%. Experiments were conducted under these optimal conditions and a pectin yield of 18.52±0.90% was obtained, which validated the model prediction. The effects of diff erent drying methods (freeze drying, spray drying and vacuum drying) on the properties of Jerusalem artichoke pectin were evaluated and they were compared with apple pectin. FTIR spectral analysis showed no major structural diff erences in Jerusalem artichoke pectin samples produced by various drying treatments. The antioxidant activities of pectin dried by diff erent methods were investigated using in vitro hydroxyl and DPPH radical scavenging systems. The results revealed that the activities of spray dried pectin (SDP) and apple pectin (AP) were stronger than those of vacuum oven dried pectin (ODP) and vacuum freeze dried pectin (FDP). Therefore compared with the other two drying methods, the spray drying method was the best.

Analysis of the microbiota of refrigerated chopped parsley after treatments with a coating containing enterocin AS-48 or by high-hydrostatic pressure.

PubMed

Grande Burgos, María José; López Aguayo, María Del Carmen; Pérez Pulido, Rubén; Galvez, Antonio; Lucas, Rosario

2017-09-01

Parsley can be implicated in foodborne illness, yet chopped parsley is used as an ingredient or garnish for multiple dishes. The aim of the present study was to determine the effect of two different treatments on the bacterial diversity of parsley: (i) coating with a pectin-EDTA solution containing the circular bacteriocin enterocin AS-48, and (ii) treatment by high hydrostatic pressure (HHP) at 600MPa for 8min. Control and treated parsley were stored in trays at 5°C for 10days. Both treatments reduced viable counts by 3.7 log cycles and retarded growth of survivors during storage. The bacterial diversity of the chopped parsley was studied by high throughput sequencing (Illumina Miseq). Bacterial diversity of control samples mainly consists of Proteobacteria (96.87%) belonging to genera Pseudomonas (69.12%), Rheinheimera (8.56%) and Pantoea (6.91%) among others. During storage, the relative abundance of Bacteroidetes (mainly Flavobacterium and Sphingobacterium) increased to 26.66%. Application of the pectin-bacteriocin-EDTA coating reduced the relative abundance of Proteobacteria (63.75%) and increased that of Firmicutes (34.70%). However, the relative abundances of certain groups such as Salmonella, Shigella and Acinetobacter increased at early storage times. Late storage was characterized by an increase in the relative abundance of Proteobacteria, mainly Pseudomonas. Upon application of HHP treatment, the relative abundance of Proteobacteria was reduced (85.88%) while Actinobacteria increased (8.01%). During early storage of HHP-treated samples, the relative abundance of Firmicutes increased. Potentially-pathogenic bacteria (Shigella) only increased in relative abundance by the end of storage. Results of the present study indicate that the two treatments had different effects on the bacterial diversity of parsley. The HHP treatment provided a safer product, since no potentially-pathogenic bacteria were detected until the end of the storage period. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tissue Specific Localization of Pectin–Ca2+ Cross-Linkages and Pectin Methyl-Esterification during Fruit Ripening in Tomato (Solanum lycopersicum)

PubMed Central

Hyodo, Hiromi; Terao, Azusa; Furukawa, Jun; Sakamoto, Naoya; Yurimoto, Hisayoshi; Satoh, Shinobu; Iwai, Hiroaki

2013-01-01

Fruit ripening is one of the developmental processes accompanying seed development. The tomato is a well-known model for studying fruit ripening and development, and the disassembly of primary cell walls and the middle lamella, such as through pectin de-methylesterified by pectin methylesterase (PE) and depolymerization by polygalacturonase (PG), is generally accepted to be one of the major changes that occur during ripening. Although many reports of the changes in pectin during tomato fruit ripening are focused on the relation to softening of the pericarp or the Blossom-end rot by calcium (Ca2+) deficiency disorder, the changes in pectin structure and localization in each tissues during tomato fruit ripening is not well known. In this study, to elucidate the tissue-specific role of pectin during fruit development and ripening, we examined gene expression, the enzymatic activities involved in pectin synthesis and depolymerisation in fruit using biochemical and immunohistochemical analyses, and uronic acids and calcium (Ca)-bound pectin were determined by secondary ion-microprobe mass spectrometry. These results show that changes in pectin properties during fruit development and ripening have tissue-specific patterns. In particular, differential control of pectin methyl-esterification occurs in each tissue. Variations in the cell walls of the pericarp are quite different from that of locular tissues. The Ca-binding pectin and hairy pectin in skin cell layers are important for intercellular and tissue–tissue adhesion. Maintenance of the globular form and softening of tomato fruit may be regulated by the arrangement of pectin structures in each tissue. PMID:24236073

Cellulose-pectin composite hydrogels: Intermolecular interactions and material properties depend on order of assembly.

PubMed

Lopez-Sanchez, Patricia; Martinez-Sanz, Marta; Bonilla, Mauricio R; Wang, Dongjie; Gilbert, Elliot P; Stokes, Jason R; Gidley, Michael J

2017-04-15

Plant cell walls have a unique combination of strength and flexibility however, further investigations are required to understand how those properties arise from the assembly of the relevant biopolymers. Recent studies indicate that Ca 2+ -pectates can act as load-bearing components in cell walls. To investigate this proposed role of pectins, bioinspired wall models were synthesised based on bacterial cellulose containing pectin-calcium gels by varying the order of assembly of cellulose/pectin networks, pectin degree of methylesterification and calcium concentration. Hydrogels in which pectin-calcium assembly occurred prior to cellulose synthesis showed evidence for direct cellulose/pectin interactions from small-angle scattering (SAXS and SANS), had the densest networks and the lowest normal stress. The strength of the pectin-calcium gel affected cellulose structure, crystallinity and material properties. The results highlight the importance of the order of assembly on the properties of cellulose composite networks and support the role of pectin in the mechanics of cell walls. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cerium Binding Activity of Pectins Isolated from the Seagrasses Zostera marina and Phyllospadix iwatensis

PubMed Central

Khotimchenko, Yuri; Khozhaenko, Elena; Kovalev, Valeri; Khotimchenko, Maxim

2012-01-01

Cerium binding activity of three different water soluble pectin compounds of different origin was studied in a batch sorption system. The Langmuir, Freundlich and BET sorption models were adopted to describe the binding reactions between metal ions and pectin molecules. The Langmuir model provided the best fit. Within the pH range from 4.0 to 6.0, the largest amount of the cerium ions was bound by pectin isolated from the seagrass Phylospadix iwatensis in comparison to pectin extracted from the seagrass Zostera marina and pectin obtained from citrus peel (commercial grade). The Langmuir constants were also highest for the pectin samples isolated from the seagrass P. iwatensis. The results obtained from this study suggest that pectin is a prospective source for the development of radioisotope-removing pharmaceuticals. PMID:22690146

Enzyme-Encapsulated Liposome-Linked Immunosorbent Assay Enabling Sensitive Personal Glucose Meter Readout for Portable Detection of Disease Biomarkers.

PubMed

Lin, Bingqian; Liu, Dan; Yan, Jinmao; Qiao, Zhi; Zhong, Yunxin; Yan, Jiawei; Zhu, Zhi; Ji, Tianhai; Yang, Chaoyong James

2016-03-23

There is considerable demand for sensitive, selective, and portable detection of disease-associated proteins, particularly in clinical practice and diagnostic applications. Portable devices are highly desired for detection of disease biomarkers in daily life due to the advantages of being simple, rapid, user-friendly, and low-cost. Herein we report an enzyme-encapsulated liposome-linked immunosorbent assay for sensitive detection of proteins using personal glucose meters (PGM) for portable quantitative readout. Liposomes encapsulating a large amount of amyloglucosidase or invertase are surface-coated with recognition elements such as aptamers or antibodies for target recognition. By translating molecular recognition signal into a large amount of glucose with the encapsulated enzyme, disease biomarkers such as thrombin or C-reactive protein (CRP) can be quantitatively detected by a PGM with a high detection limit of 1.8 or 0.30 nM, respectively. With the advantages of portability, ease of use, and low-cost, the method reported here has potential for portable and quantitative detection of various targets for different POC testing scenarios, such as rapid diagnosis in clinic offices, health monitoring at the bedside, and chemical/biochemical safety control in the field.

A New Route to Liposil Formation by an Interfacial Sol-Gel Process Confined by Lipid Bilayer.

PubMed

Shen, Shukun; Yang, Lu; Lu, Yaxing; Chen, Jian-Gang; Song, Shaofei; Hu, Daodao; Parikh, Atul

2015-11-18

We report a new and simple approach to prepare a class of silica-reinforced liposomes with hybrid core-shell nanostructures. The amphiphilic natural structure of lipids was exploited to sequester hydrophobic molecules, namely precursor TEOS and pyrene, in the hydrophobic midplane of liposomal bilayer assemblies in the aqueous phase. Subsequent interfacial hydrolysis of TEOS at the bilayer/water interface and ensuing condensation within the hydrophobic interstices of the lipid bilayer drives silica formation in situ, producing a novel class of silica-lipid hybrid liposils. Structural characterization by scanning- and transmission electron microscopy confirm that the liposils so generated preserve closed topologies and size-monodipersity of the parent lecithin liposomes, and DSC-TGA and XRD measurements provide evidence for the silica coating. Monitoring fluorescence measurements using embedded pyrene yield detailed information on microenvironment changes, which occur during sol-gel process and shed light on the structural evolution during silica formation. We envisage that liposils formed by this simple, new approach, exploiting the hydrophobic core of the lipid bilayer to spatially localize silica-forming precursors enables preparation of stable liposils exhibiting capacity for cargo encapsulation, bicompatibility, and fluorescence monitoring, more generally opening a window for construction of stable, functional hybrid materials.

Optimization of acoustic liposomes for improved in vitro and in vivo stability.

PubMed

Sax, Nicolas; Kodama, Tetsuya

2013-01-01

Liposomes encapsulating perfluoropropane gas, termed acoustic liposomes (ALs), which can serve both for ultrasound (US) imaging and US-mediated gene delivery, have been reported. However, the echogenicity of ALs decreases within minutes in vivo due to gas diffusion and leakage, hindering time-consuming procedures such as contrast-enhanced 3D US imaging and raising the need for improvement of their stability. The stability of ALs preparations incorporating increasing ratios of anionic / unsaturated phospholipids, polyethylene glycol (PEG)ylated phospholipid and cholesterol was investigated by measurement of their reflectivity over time using a high-frequency US imaging system, both in vitro and in vivo. The retention of echogenicity of ALs in vitro is enhanced with increasing molar ratios of PEGylated lipids. Addition of 10 molar percent of an anionic phospholipid resulted in a 31% longer half-life, while cholesterol had the opposite effect. Assessment of the stability of an optimized composition showed a more than 2-fold increase of the detection half-life in mice. Presence of a PEG coating not only serves to provide "stealth" properties in vivo, but also contributes to the retention of the encapsulated gas. The optimized ALs reported here can be used as a contrast agent for lengthier imaging procedures.

Macromolecular Assemblage in the Design of a Synthetic AIDS Vaccine

NASA Astrophysics Data System (ADS)

Defoort, Jean-Philippe; Nardelli, Bernardetta; Huang, Wolin; Ho, David D.; Tam, James P.

1992-05-01

We describe a peptide vaccine model based on the mimicry of surface coat protein of a pathogen. This model used a macromolecular assemblage approach to amplify peptide antigens in liposomes or micelles. The key components of the model consisted of an oligomeric lysine scaffolding to amplify peptide antigens covalently 4-fold and a lipophilic membrane-anchoring group to further amplify noncovalently the antigens many-fold in liposomal or micellar form. A peptide antigen derived from the third variable domain of glycoprotein gp120 of human immunodeficiency virus type 1 (HIV-1), consisting of neutralizing, T-helper, and T-cytotoxic epitopes, was used in a macromolecular assemblage model (HIV-1 linear peptide amino acid sequence 308-331 in a tetravalent multiple antigen peptide system linked to tripalmitoyl-S-glycerylcysteine). The latter complex, in liposome or micelle, was used to immunize mice and guinea pigs without any adjuvant and found to induce gp120-specific antibodies that neutralize virus infectivity in vitro, elicit cytokine production, and prime CD8^+ cytotoxic T lymphocytes in vivo. Our results show that the macromolecular assemblage approach bears immunological mimicry of the gp120 of HIV virus and may lead to useful vaccines against HIV infection.

Development of New Contrast Agents for Imaging Function and Metabolism by Magnetic Resonance Imaging

PubMed Central

Carvalho, Alexandra; Gonçalves, M Clara; Corvo, M Luísa; Martins, M Bárbara F

2017-01-01

Liposomes are interesting nanosystems with a wide range of medical application. One particular application is their ability to enhance contrast in magnetic resonance images; when properly loaded with magnetic/superparamagnetic nanoparticles, this means to act as contrast agents. The design of liposomes loaded with magnetic particles, magnetoliposomes, presents a large number of possibilities depending on the application from image function to metabolism. More interesting is its double function application as theranostics (diagnostics and therapy). The synthesis, characterization, and possible medical applications of two types of magnetoliposomes are reviewed. Their performance will be compared, in particular, their efficiency as contrast agents for magnetic resonance imaging, measured by their relaxivities r1 and r2 relating to their particular composition. One of the magnetoliposomes had 1,2-diacyl-sn-glycero-3-phosphocholine (soy) as the main phospholipid component, with and without cholesterol, varying its phospholipid to cholesterol molar ratios. The other formulation is a long-circulating liposome composed of 1,2-diacyl-sn-glycero-3-phosphocholine (egg), cholesterol, and 1,2-distearoyl-sn-glycerol-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000]. Both nanosystems were loaded with superparamagnetic iron oxide nanoparticles with different sizes and coatings. PMID:28804244

E-selectin liposomal and nanotube-targeted delivery of doxorubicin to circulating tumor cells

PubMed Central

Mitchell, Michael J.; Chen, Christina S.; Ponmudi, Varun; Hughes, Andrew D.; King, Michael R.

2012-01-01

The presence of circulating tumor cells (CTCs) is believed to lead to the formation of secondary tumors via an adhesion cascade involving interaction between adhesion receptors of endothelial cells and ligands on CTCs. Many CTCs express sialylated carbohydrate ligands on their surfaces that adhere to selectin protein found on inflamed endothelial cells. We have investigated the feasibility of using immobilized selectin proteins as a targeting mechanism for CTCs under flow. Herein, targeted liposomal doxorubicin (L-DXR) was functionalized with recombinant human E-selectin (ES) and polyethylene glycol (PEG) to target and kill cancer cells under shear flow, both when immobilized along a microtube device or sheared in a cone-and-plate viscometer in a dilute suspension. Healthy circulating cells such as red blood cells were not targeted by this mechanism and were left to freely circulate, and minimal leukocyte death was observed. Halloysite nanotube (HNT)-coated microtube devices immobilized with nanoscale liposomes significantly enhanced the targeting, capture, and killing of cancer cells. This work demonstrates that E-selectin functionalized L-DXR, sheared in suspension or immobilized onto microtube devices, provides a novel approach to selectively target and deliver chemotherapeutics to CTCs in the bloodstream. PMID:22421423

Low-Temperature Blanching as a Tool to Modulate the Structure of Pectin in Blueberry Purees.

PubMed

Chevalier, Laura M; Rioux, Laurie-Eve; Angers, Paul; Turgeon, Sylvie L

2017-09-01

Blueberry composition was characterized for 6 cultivars. It contains a good amount of dietary fiber (10% to 20%) and pectin (4% to 7%) whose degree of methylation (DM) is sensitive to food processing. A low temperature blanching (LTB: 60 °C/1 h) was applied on blueberry purees to decrease pectin DM, in order to modulate puree properties and functionalities (that is, viscosity and stability), and to enhance pectin affinity toward other components within food matrices. Fiber content, viscosity, pectin solubility, DM, and monosaccharide composition were determined for both pasteurized, and LTB+pasteurized blueberry purees. The results showed that neither the amount of fiber, nor the viscosity were affected by LTB, indicating that this treatment did not result in any significant pectin depolymerization and degradation. LTB caused a decrease both in pectin DM from 58-67% to 45-47% and in the amount of water-soluble pectin fraction, the latter remaining the major fraction of total pectin at 52% to 57%. A LTB is a simple and mild process to produce blueberry purees with mostly soluble and low-methylated pectin in order to extend functionality and opportunities for interactions with other food ingredients. © 2017 Institute of Food Technologists®.

In vitro β-Carotene Bioaccessibility and Lipid Digestion in Emulsions: Influence of Pectin Type and Degree of Methyl-Esterification.

PubMed

Verrijssen, Tina A J; Christiaens, Stefanie; Verkempinck, Sarah H E; Boeve, Jeroen; Grauwet, Tara; Van Loey, Ann M; Salvia-Trujillo, Laura; Hendrickx, Marc E

2016-10-01

Citrus pectin (CP) and sugar beet pectin (SBP) were demethoxylated and fully characterized in terms of pectin properties in order to investigate the influence of the pectin degree of methyl-esterification (DM) and the pectin type on the in vitro β-carotene bioaccessibility and lipid digestion in emulsions. For the CP based emulsions containing β-carotene enriched oil, water and pectin, the β-carotene bioaccessibility, and lipid digestion were higher in the emulsions with pectin with a higher DM (57%; "CP57 emulsion") compared to the emulsions with pectin with a lower DM (30%; "CP30 emulsion") showing that the DM plays an important role. In contrast, in SBP-based emulsions, nor β-carotene bioaccessibility nor lipid digestion were dependent on pectin DM. Probably here, other pectin properties are more important factors. It was observed that β-carotene bioaccessibility and lipid digestion were lower in the CP30 emulsion in comparison with the CP57, SBP32, and SBP58 emulsions. However, the β-carotene bioaccessibility of CP57 emulsion was similar to that of the SBP emulsions, whereas the lipid digestion was not. It seems that pectin type and pectin DM (in case of CP) are determining which components can be incorporated into micelles. Because carotenoids and lipids have different structures and polarities, their incorporation may be different. This knowledge can be used to engineer targeted (digestive) functionalities in food products. If both high β-carotene bioaccessibility and high lipid digestion are targeted, SBP emulsions are the best options. The CP57 emulsion can be chosen if high β-carotene bioaccessibility but lower lipid digestion is desired. © 2016 Institute of Food Technologists®.

Characterization of citrus pectin samples extracted under different conditions: influence of acid type and pH of extraction

PubMed Central

Kaya, Merve; Sousa, António G.; Crépeau, Marie-Jeanne; Sørensen, Susanne O.; Ralet, Marie-Christine

2014-01-01

Background and Aims Pectin is a complex macromolecule, the fine structure of which is influenced by many factors. It is used as a gelling, thickening and emulsifying agent in a wide range of applications, from food to pharmaceutical products. Current industrial pectin extraction processes are based on fruit peel, a waste product from the juicing industry, in which thousands of tons of citrus are processed worldwide every year. This study examines how pectin components vary in relation to the plant source (orange, lemon, lime, grapefruit) and considers the influence of extraction conditions on the chemical and macromolecular characteristics of pectin samples. Methods Citrus peel (orange, lemon, lime and grapefruit) from a commercial supplier was used as raw material. Pectin samples were obtained on a bulk plant scale (kilograms; harsh nitric acid, mild nitric acid and harsh oxalic acid extraction) and on a laboratory scale (grams; mild oxalic acid extraction). Pectin composition (acidic and neutral sugars) and physicochemical properties (molar mass and intrinsic viscosity) were determined. Key Results Oxalic acid extraction allowed the recovery of pectin samples of high molecular weight. Mild oxalic acid-extracted pectins were rich in long homogalacturonan stretches and contained rhamnogalacturonan I stretches with conserved side chains. Nitric acid-extracted pectins exhibited lower molecular weights and contained rhamnogalacturonan I stretches encompassing few and/or short side chains. Grapefruit pectin was found to have short side chains compared with orange, lime and lemon. Orange and grapefruit pectin samples were both particularly rich in rhamnogalacturonan I backbones. Conclusions Structural, and hence macromolecular, variations within the different citrus pectin samples were mainly related to their rhamnogalacturonan I contents and integrity, and, to a lesser extent, to the length of their homogalacturonan domains. PMID:25081519

Modulation of Endosomal Escape of IRQ-PEGylated Nano-carrier

NASA Astrophysics Data System (ADS)

Mudhakir, Diky; Akita, Hidetaka; Harashima, Hideyoshi

2011-12-01

The novel IRQ peptide is one of cell penetrating peptides (CPPs) that has ability to induce endosomal escape. It has been demonstrated that IRQ ligand had ability to facilitate an escape of liposomes encapsulating siRNA from the endosomes presumably by fusion-independent mechanism [1,2]. In the present study, we attempted to modulate the intracellular trafficking of IRQ-modified nano-carrier in term of escaping process by changing the lipid composition. The peptide was attached to the terminal end of maleimide group of polyethylene glycol-modified liposomes (IRQ-PEG-Lip). The liposomes were composed of DOTAP, DOPE and cholesterol and it was labeled by water soluble sulpho-rhodamine B (Sr-B). The escape of PEG-coated liposomes was then observed by confocal laser scanning microscope after the endosomes were stained with Lysosensor. The results exhibited that IRQ-PEG-Lip was escaped from endosomal compartment after 1 h transfection when 40% of DOPE was incorporated into the nanostructure comparing to that of PEG-Lip. These results are consistent with the previous results that the IRQ facilitates endosomal escape via independent-mechanism. However, IRQ-PEG-Lip were then completely co-localized in the acidic compartment when density of DOPE was reduced approximately 20%. These results indicated that the utilizing of DOPE is important for the escape process even in the presence of hydrophilic PEG polymer. In conclusion, the regulation of endosomal escape ability of the PEGylated-IRQ nano-carrier was induced by fusion-independent manner as well as fusogenic lipid.

The ectopic expression of a pectin methyl esterase inhibitor increases pectin methyl esterification and limits fungal diseases in wheat.

PubMed

Volpi, Chiara; Janni, Michela; Lionetti, Vincenzo; Bellincampi, Daniela; Favaron, Francesco; D'Ovidio, Renato

2011-09-01

Cell wall pectin methyl esterification can influence plant resistance because highly methyl-esterified pectin can be less susceptible to the hydrolysis by pectic enzymes such as fungal endopolygalacturonases (PG). Pectin is secreted into the cell wall in a highly methyl-esterified form and, here, is de-methyl esterified by pectin methyl esterase (PME). The activity of PME is controlled by specific protein inhibitors called PMEI; consequently, an increased inhibition of PME by PMEI might modify the pectin methyl esterification. In order to test the possibility of improving wheat resistance by modifying the methyl esterification of pectin cell wall, we have produced durum wheat transgenic lines expressing the PMEI from Actinidia chinensis (AcPMEI). The expression of AcPMEI endows wheat with a reduced endogenous PME activity, and transgenic lines expressing a high level of the inhibitor showed a significant increase in the degree of methyl esterification. These lines showed a significant reduction of disease symptoms caused by the fungal pathogens Bipolaris sorokiniana or Fusarium graminearum. This increased resistance was related to the impaired ability of these fungal pathogens to grow on methyl-esterified pectin and to a reduced activity of the fungal PG to hydrolyze methyl-esterified pectin. In addition to their importance for wheat improvement, these results highlight the primary role of pectin despite its low content in the wheat cell wall.

Sequential ultrasound-microwave assisted acid extraction (UMAE) of pectin from pomelo peels.

PubMed

Liew, Shan Qin; Ngoh, Gek Cheng; Yusoff, Rozita; Teoh, Wen Hui

2016-12-01

This study aims to optimize sequential ultrasound-microwave assisted extraction (UMAE) on pomelo peel using citric acid. The effects of pH, sonication time, microwave power and irradiation time on the yield and the degree of esterification (DE) of pectin were investigated. Under optimized conditions of pH 1.80, 27.52min sonication followed by 6.40min microwave irradiation at 643.44W, the yield and the DE value of pectin obtained was respectively at 38.00% and 56.88%. Based upon optimized UMAE condition, the pectin from microwave-ultrasound assisted extraction (MUAE), ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) were studied. The yield of pectin adopting the UMAE was higher than all other techniques in the order of UMAE>MUAE>MAE>UAE. The pectin's galacturonic acid content obtained from combined extraction technique is higher than that obtained from sole extraction technique and the pectin gel produced from various techniques exhibited a pseudoplastic behaviour. The morphological structures of pectin extracted from MUAE and MAE closely resemble each other. The extracted pectin from UMAE with smaller and more regular surface differs greatly from that of UAE. This has substantiated the highest pectin yield of 36.33% from UMAE and further signified their compatibility and potentiality in pectin extraction. Copyright © 2016 Elsevier B.V. All rights reserved.

[Polymer and oligomer based doxorubicin carriers].

PubMed

Kik, Krzysztof; Lwow, Felicja; Szmigiero, Leszek

2007-01-01

Doxorubicin and other anthracycline derivatives play an important role in the treatment of many malignant diseases. Unfortunately, clinical effectiveness of this class of drugs is limited by cumulative cardiotoxicity which occurs in significant percentage of patients at cumulative dose in the range 450-600 mg/m2. Therefore, several strategies have been developed to reduce cardiotoxicity of doxorubicin and its analogues. One of the possible ways leading to the improvement of anticancer selectivity of doxorubicin is the design of polymer and olygomer carriers which may transport drug molecules more efficiently and more specifically. Synthetic polymers are of increasing interest as therapeutic agents owing to their enhanced pharmacokinetic profiles relative to small molecule drugs. Currently a new class of multifunctional polymers is being prepared that can "mask" biologically active compounds, such as cytotoxic agents, until they reach target sites, but which can then release the agent in situ to effect the therapy. The legitimacy of the development of polymer based doxorubicine carriers is supported by the growing number of clinical reports indicating that the use of hydrophilic polymers or polymer coated liposomes as a platform for delivery of the drug results in better therapeutic effects than the free drug. In this article we present the most promising strategies directed at the development of improved anthracycline drugs formulations based of polymer and olygomer carriers. We review: 1) polyethylenoglycol-coated ("pegylated") liposomal doxorubicin; 2) extracellulary tumor-activated prodrugs which are conjugates of doxorubicin with peptides; 3) doxorubicin coated by higly polymerised glycosoaminoglycans; 4) conjugates of doxorubicin with copolymer of N-(2-hydroxypropyl)methacrylamide.

Pectin extraction from lemon by-product with acidified date juice: rheological properties and microstructure of pure and mixed pectin gels.

PubMed

Masmoudi, M; Besbes, S; Ben Thabet, I; Blecker, C; Attia, H

2010-04-01

The microstructure and the rheological properties of lemon-pectin mixtures were studied and compared to those of pure lemon (high methoxyl: HM) and date (low methoxyl: LM) pectins. Rheological properties were carried out in the presence of 30%, 45% and 60% sucrose, and increasing calcium concentrations (0-0.1%). The presence of date with lemon pectin led to a gel formation at 45% sucrose and in the presence of calcium, which was not the case for lemon pectin alone under the same conditions. It is suggested that lemon and date pectins interacted, leading to gel formations at different gelling temperatures, which were strongly dependent on degree of methylation. These results were confirmed by scanning electron microscopy, which revealed inhomogeneous gels where dense aggregated network and loose, open network areas were present. Addition of calcium to pectin mixture gels led to stronger and faster gel formation.

Pectin is not pectin: a randomized trial on the effect of different physicochemical properties of dietary fiber on appetite and energy intake.

PubMed

Wanders, Anne J; Feskens, Edith J M; Jonathan, Melliana C; Schols, Henk A; de Graaf, Cees; Mars, Monica

2014-04-10

An increased intake of dietary fiber has been associated with reduced appetite and reduced energy intake. Research on the effects of seemingly identical classes of dietary fiber on appetite has, however, resulted in conflicting findings. The present study investigated the effects of different fiber properties, including methods of supplementation, on appetite and energy intake. This was a randomized crossover study with 29 subjects (21±2 y, BMI: 21.9±1.8 kg/m(2)) consuming dairy based liquid test products (1.5 MJ, 435 g) containing either: no pectin, bulking pectin (10 g), viscous pectin (10 g), or gelled pectin (10 g). The gelled pectin was also supplemented as capsules (10 g), and as liquid (10 g). Physicochemical properties of the test products were assessed. Appetite, glucose, insulin and gastric emptying were measured before ingestion and after fixed time intervals. Energy intake was measured after 3 h. Preload viscosity was larger for gelled>viscous>bulking>no pectin, and was larger for gelled>liquid>capsules. Appetite was reduced after ingestion of gelled pectin compared to bulking (p<0.0001), viscous (p=0.005) and no pectin (p<0.0001), without differences in subsequent energy intake (p=0.32). Gastric emptying rate was delayed after gelled pectin (82±18 min) compared to no pectin (70±19 min, p=0.015). Furthermore, gelled (p=0.002) and viscous (p<0.0001) pectin lowered insulin responses compared to no pectin, with minor reductions in glucose response. Regarding methods of supplementation, appetite was reduced after ingestion of the gelled test product compared to after capsules (p<0.0001) and liquid (p<0.0001). Energy intake was lower after ingestion of capsules compared to liquid (-12.4%, p=0.03). Different methods of supplementation resulted in distinct metabolic parameters. Results suggest that different physicochemical properties of pectin, including methods of supplementation, impact appetite and energy intake differently. Reduced appetite was probably mediated by preload physical properties, whereas inconsistent associations with metabolic parameters were found. Copyright © 2014 Elsevier Inc. All rights reserved.

Electrospinning pectin-based nanofibers: a parametric and cross-linker study

NASA Astrophysics Data System (ADS)

McCune, Devon; Guo, Xiaoru; Shi, Tong; Stealey, Samuel; Antrobus, Romare; Kaltchev, Matey; Chen, Junhong; Kumpaty, Subha; Hua, Xiaolin; Ren, Weiping; Zhang, Wujie

2018-02-01

Pectin, a natural biopolymer mainly derived from citrus fruits and apple peels, shows excellent biodegradable and biocompatible properties. This study investigated the electrospinning of pectin-based nanofibers. The parameters, pectin:PEO (polyethylene oxide) ratio, surfactant concentration, voltage, and flow rate, were studied to optimize the electrospinning process for generating the pectin-based nanofibers. Oligochitosan, as a novel and nonionic cross-liker of pectin, was also researched. Nanofibers were characterized by using AFM, SEM, and FTIR spectroscopy. The results showed that oligochitosan was preferred over Ca2+ because it cross-linked pectin molecules without negatively affecting the nanofiber morphology. Moreover, oligochitosan treatment produced a positive surface charge of nanofibers, determined by zeta potential measurement, which is desired for tissue engineering applications.

Mucoadhesive Properties of Thiolated Pectin-Based Pellets Prepared by Extrusion-Spheronization Technique.

PubMed

Martins, André Luiz Lopes; de Oliveira, Aline Carlos; do Nascimento, Carolina Machado Ozório Lopes; Silva, Luís Antônio Dantas; Gaeti, Marilisa Pedroso Nogueira; Lima, Eliana Martins; Taveira, Stephânia Fleury; Fernandes, Kátia Flávia; Marreto, Ricardo Neves

2017-05-01

The aim of this study was to develop mucoadhesive pellets on a thiolated pectin base using the extrusion-spheronization technique. Thiolation of pectin was performed by esterification with thioglycolic acid. The molecular weight and thiol group content of the pectins were determined. Pellets containing pectin, microcrystalline cellulose, and ketoprofen were prepared and their mucoadhesive properties were evaluated through a wash-off test using porcine intestinal mucosa. The in vitro ketoprofen release was also evaluated. Thiolated pectin presented a thiol group content of 0.69 mmol/g. Thiolation caused a 13% increase in polymer molecular weight. Pellets containing thiolated pectin were still adhering to the intestinal mucosa after 480 min and showed a more gradual release of ketoprofen. Conversely, pellets prepared with nonthiolated pectin showed rapid disintegration and detached after only 15 min. It can be concluded that thiolated pectin-based pellets can be considered a potential platform for the development of mucoadhesive drug delivery systems for the oral route. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Effects of Apple Juice Concentrate, Blackcurrant Concentrate and Pectin Levels on Selected Qualities of Apple-Blackcurrant Fruit Leather.

PubMed

Diamante, Lemuel M; Li, Siwei; Xu, Qianqian; Busch, Janette

2013-09-12

A study was conducted to determine the effects of different levels of apple juice concentrate (AJC), blackcurrant concentrate (BCC) and pectin on the moisture content, water activity, color, texture and ascorbic acid content of apple-blackcurrant fruit leather using the response surface methodology. The results showed the moisture content increased with increasing pectin level and with greater increases at higher AJC and BCC levels while the water activity increased with increasing pectin level and with increasing AJC level, at low pectin levels, but with decreasing AJC, at high pectin levels. The chroma decreased with increasing pectin level and with lower values at the middle AJC level. The puncturing force decreased with increasing AJC level but with a lower value at the middle pectin level. Lastly, the ascorbic acid content increased with increasing BCC level regardless of AJC and pectin levels. There is a need to reduce the drying temperature or time of apple-blackcurrant fruit leather just enough to bring the water activity closer to 0.60, thereby increasing the moisture content resulting in higher product yield.

Molecular structural differences between low methoxy pectins induced by pectin methyl esterase II: effects on texture, release and perception of aroma in gels of similar modulus of elasticity.

PubMed

Kim, Yang; Kim, Young-Suk; Yoo, Sang-Ho; Kim, Kwang-Ok

2014-02-15

Six low-methoxy pectins with different degrees of methylesterification and amidation, and molecular weights were used to prepare gels with similar moduli of elasticity by varying the concentrations of pectin and calcium phosphate. Five aroma compounds were added to the gels and their sensory textural properties, release and perception of aromas were investigated. Sensory firmness, springiness, adhesiveness, chewiness and cohesiveness differed according to the gel type, even though the moduli of elasticity were not significantly different (p<0.05). Release and perception of aromas also displayed significant difference according to the gel type (p<0.05). Low-methoxy amidated pectin exhibited the lowest release and perception for all the aroma compounds, while pectin-methylesterase-treated pectin gels exhibited relatively higher aroma release and perception. These results showed that the structural properties of pectins and gelling factors that increase the non-polar character of the gel matrices could decrease the release and perception of aromas in pectin gel systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of Apple Juice Concentrate, Blackcurrant Concentrate and Pectin Levels on Selected Qualities of Apple-Blackcurrant Fruit Leather

PubMed Central

Diamante, Lemuel M.; Li, Siwei; Xu, Qianqian; Busch, Janette

2013-01-01

A study was conducted to determine the effects of different levels of apple juice concentrate (AJC), blackcurrant concentrate (BCC) and pectin on the moisture content, water activity, color, texture and ascorbic acid content of apple-blackcurrant fruit leather using the response surface methodology. The results showed the moisture content increased with increasing pectin level and with greater increases at higher AJC and BCC levels while the water activity increased with increasing pectin level and with increasing AJC level, at low pectin levels, but with decreasing AJC, at high pectin levels. The chroma decreased with increasing pectin level and with lower values at the middle AJC level. The puncturing force decreased with increasing AJC level but with a lower value at the middle pectin level. Lastly, the ascorbic acid content increased with increasing BCC level regardless of AJC and pectin levels. There is a need to reduce the drying temperature or time of apple-blackcurrant fruit leather just enough to bring the water activity closer to 0.60, thereby increasing the moisture content resulting in higher product yield. PMID:28239127

Short-Term Boron Deprivation Inhibits Endocytosis of Cell Wall Pectins in Meristematic Cells of Maize and Wheat Root Apices1

PubMed Central

Yu, Qin; Hlavacka, Andrej; Matoh, Toru; Volkmann, Dieter; Menzel, Diedrik; Goldbach, Heiner E.; Baluška, František

2002-01-01

By using immunofluorescence microscopy, we observed rapidly altered distribution patterns of cell wall pectins in meristematic cells of maize (Zea mays) and wheat (Triticum aestivum) root apices. This response was shown for homogalacturonan pectins characterized by a low level (up to 40%) of methylesterification and for rhamnogalacturonan II pectins cross-linked by a borate diol diester. Under boron deprivation, abundance of these pectins rapidly increased in cell walls, whereas their internalization was inhibited, as evidenced by a reduced and even blocked accumulation of these cell wall pectins within brefeldin A-induced compartments. In contrast, root cells of species sensitive to the boron deprivation, like zucchini (Cucurbita pepo) and alfalfa (Medicago sativa), do not internalize cell wall pectins into brefeldin A compartments and do not show accumulation of pectins in their cell walls under boron deprivation. For maize and wheat root apices, we favor an apoplastic target for the primary action of boron deprivation, which signals deeper into the cell via endocytosis-mediated pectin signaling along putative cell wall-plasma membrane-cytoskeleton continuum. PMID:12226520

Multilayer engineered nanoliposomes as a novel tool for oral delivery of lipopeptide-based vaccines against group A Streptococcus.

PubMed

Marasini, Nirmal; Giddam, Ashwini K; Ghaffar, Khairunnisa A; Batzloff, Michael R; Good, Michael F; Skwarczynski, Mariusz; Toth, Istvan

2016-05-01

To develop an oral nanovaccine delivery system for lipopeptide-based vaccine candidate against group A Streptococcus. Lipid-core peptide-1-loaded nanoliposomes were prepared as a template and coated with opposite-charged polyelectrolytes to produce particles with size <200 nm. Efficacy of this oral nanovaccine delivery system was evaluated in mice model. Polymer-coated liposomes produced significantly higher antigen-specific mucosal IgA and systemic IgG titers in comparison to vaccine formulated with a strong mucosal adjuvant upon oral immunization in mice. Moreover, high levels of systemic antibody titers were retained even at day 185 postprimary immunization. Efficient oral delivery platform for lipopeptide-based vaccines has been developed.

Ultrasound effects on the degradation kinetics, structure and rheological properties of apple pectin.

PubMed

Zhang, Lifen; Ye, Xinqian; Ding, Tian; Sun, Xiaoyang; Xu, Yuting; Liu, Donghong

2013-01-01

The effects of ultrasound on the molecular weight of apple pectin were investigated. The structure and rheological properties of the degradation products were also tentatively identified by High Performance Liquid Chromatography-Photodiode Array Detector (HPLC-PAD), Infrared spectroscopy (IR), Nuclear Magnetic Resonance spectroscopy (NMR) and Rheometer. The results indicated that the weight-average molecular weight of apple pectin decreased obviously after ultrasound treatment. The molecular weight of degradation products had a uniform and narrow distribution. Ultrasound intensity and temperature play an important role in the degradation reaction. Degradation kinetics model of apple pectin fitted to 1/M(t) - 1/M(0) = kt from 5 to 45 °C. The degree of methylation of apple pectin reduced according to IR analysis when ultrasound was applied. Ultrasound treatment could not alter the primary structure of apple pectin according to the results determined by HPLC, IR and NMR. Meanwhile, the viscosity of apple pectin was 10(3) times as large as that of ultrasound-treated apple pectin. The ultrasound-treated apple pectin showed predominantly viscous responses (G' < G") over the same frequency range. The results suggested that ultrasound provided a viable alternative method for the modification of pectin. Copyright © 2012 Elsevier B.V. All rights reserved.

Pectin methylesterase activity in vivo differs from activity in vitro and enhances polygalacturonase-mediated pectin degradation in tabasco pepper.

PubMed

Arancibia, Ramón A; Motsenbocker, Carl E

2006-03-01

Polygalacturonase (PG) and pectin methylesterase (PME) activities were analyzed in ripening fruits of two tabasco pepper (Capsicum frutescens) lines that differ in the extent of pectin degradation (depolymerization and dissolution). Ripe 'Easy Pick' fruit is characterized by pectin ultra-degradation and easy fruit detachment from the calyx (deciduous trait), while pectin depolymerization and dissolution in ripe 'Hard Pick' fruit is limited. PG activity in protein extracts increased similarly in both lines during fruit ripening. PME activity in vivo assessed by methanol production, however, was detected only in fruit of the 'Easy Pick' line and was associated with decreased pectin methyl-esterification. In contrast, methanol production in vivo was not detected in fruits of the 'Hard Pick' line and the degree of pectin esterification remained the same throughout ripening. Consequently, a ripening specific PME that is active in vivo appears to enhance PG-mediated pectin ultra-degradation resulting in cell wall dissolution and the deciduous fruit trait. PME activity in vitro, however, was detected in protein extracts from both lines at all ripening stages. This indicates that some PME isozymes are apparently inactive in vivo, particularly in green fruit and throughout ripening in the 'Hard Pick' line, limiting PG-mediated pectin depolymerization which results in moderately difficult fruit separation from the calyx.

Polysaccharide/Surfactant complexes at the air-water interface - effect of the charge density on interfacial and foaming behaviors.

PubMed

Ropers, M H; Novales, B; Boué, F; Axelos, M A V

2008-11-18

The binding of a cationic surfactant (hexadecyltrimethylammonium bromide, CTAB) to a negatively charged natural polysaccharide (pectin) at air-solution interfaces was investigated on single interfaces and in foams, versus the linear charge densities of the polysaccharide. Besides classical methods to investigate polymer/surfactant systems, we applied, for the first time concerning these systems, the analogy between the small angle neutron scattering by foams and the neutron reflectivity of films to measure in situ film thicknesses of foams. CTAB/pectin foam films are much thicker than the pure surfactant foam film but similar for high- and low-charged pectin/CTAB systems despite the difference in structure of complexes at interfaces. The improvement of the foam properties of CTAB bound to pectin is shown to be directly related to the formation of pectin-CTAB complexes at the air-water interface. However, in opposition to surface activity, there is no specific behavior for the highly charged pectin: foam properties depend mainly upon the bulk charge concentration, while the interfacial behavior is mainly governed by the charge density of pectin. For the highly charged pectin, specific cooperative effects between neighboring charged sites along the chain are thought to be involved in the higher surface activity of pectin/CTAB complexes. A more general behavior can be obtained at lower charge density either by using a low-charged pectin or by neutralizing the highly charged pectin in decreasing pH.

Modification of citrus and apple pectin by power ultrasound: Effects of acid and enzymatic treatment.

PubMed

Muñoz-Almagro, Nerea; Montilla, Antonia; Moreno, F Javier; Villamiel, Mar

2017-09-01

Pectin-derived oligosaccharides are emerging as a new generation of functional ingredients with new or improved technological and/or bioactive properties as compared to pectin. This work addresses the impact of power ultrasound (US) on the structure of citrus and apple pectin under different experimental conditions of power, amplitude and pectin concentration in aqueous and acid media, as well as in the presence of a pectinase. Results indicated that depolymerisation of both pectin increased with time and intensity of US in aqueous media and their polydispersity decreased. In general, a higher depolymerisation was observed in pectin treated by US in the presence of nitric and citric acids than in water, and hardly any difference was detected between both types of acids. Most of the assays gave rise to high-methoxylated pectin with a degree of esterification above 50%, pointing out their suitability for potential gelling agents. Finally, US did not have any impact in assisted enzymatic hydrolysis on the degree and/or rate of depolymerisation at low and medium levels of pectin concentration (0.5 and 2%), whereas a higher diversity of pectin fragments was found at 5% which could be indicative of a more controlled depolymerisation. These findings highlight the importance of the selection of appropriate US processing conditions to diversify the applications of modified pectin, as well as the potential of US as a prospective alternative to currently used depolymerisation techniques. Copyright © 2016 Elsevier B.V. All rights reserved.

Dietary Pectin Increases Intestinal Crypt Stem Cell Survival following Radiation Injury.

PubMed

Sureban, Sripathi M; May, Randal; Qu, Dongfeng; Chandrakesan, Parthasarathy; Weygant, Nathaniel; Ali, Naushad; Lightfoot, Stan A; Ding, Kai; Umar, Shahid; Schlosser, Michael J; Houchen, Courtney W

2015-01-01

Gastrointestinal (GI) mucosal damage is a devastating adverse effect of radiation therapy. We have recently reported that expression of Dclk1, a Tuft cell and tumor stem cell (TSC) marker, 24h after high dose total-body gamma-IR (TBI) can be used as a surrogate marker for crypt survival. Dietary pectin has been demonstrated to possess chemopreventive properties, whereas its radioprotective property has not been studied. The aim of this study was to determine the effects of dietary pectin on ionizing radiation (IR)-induced intestinal stem cell (ISC) deletion, crypt and overall survival following lethal TBI. C57BL/6 mice received a 6% pectin diet and 0.5% pectin drinking water (pre-IR mice received pectin one week before TBI until death; post-IR mice received pectin after TBI until death). Animals were exposed to TBI (14 Gy) and euthanized at 24 and 84h post-IR to assess ISC deletion and crypt survival respectively. Animals were also subjected to overall survival studies following TBI. In pre-IR treatment group, we observed a three-fold increase in ISC/crypt survival, a two-fold increase in Dclk1+ stem cells, increased overall survival (median 10d vs. 7d), and increased expression of Dclk1, Msi1, Lgr5, Bmi1, and Notch1 (in small intestine) post-TBI in pectin treated mice compared to controls. We also observed increased survival of mice treated with pectin (post-IR) compared to controls. Dietary pectin is a radioprotective agent; prevents IR-induced deletion of potential reserve ISCs; facilitates crypt regeneration; and ultimately promotes overall survival. Given the anti-cancer activity of pectin, our data support a potential role for dietary pectin as an agent that can be administered to patients receiving radiation therapy to protect against radiation-induces mucositis.

Physical and oxidative stability of fish oil-in-water emulsions stabilized with beta-lactoglobulin and pectin.

PubMed

Katsuda, Marly S; McClements, D J; Miglioranza, Lucia H S; Decker, Eric A

2008-07-23

The oxidation of fatty acids can be inhibited by engineering the surface of oil-in-water emulsion droplets to decrease interactions between aqueous phase prooxidants and lipids. The objective of this research was to evaluate whether emulsions stabilized by a multilayer emulsifier systems consisting of beta-lactoglobulin and citrus or sugar beet pectin could produce fish oil-in-water emulsions that had good physical and oxidative stability. Sugar beet pectin was compared to citrus pectin because the sugar beet pectin contains the known antioxidant, ferulic acid. A primary Menhaden oil-in-water emulsion was prepared with beta-lactoglobulin upon which the pectins were electrostatically deposited at pH 3.5. Emulsions prepared with 1% oil, 0.05% beta-lactoglobulin, and 0.06% pectins were physically stable for up to 16 days. As determined by monitoring lipid hydroperoxide and headspace propanal formation, emulsions prepared with the multilayer system of beta-lactoglobulin and citrus pectin were more stable than emulsions stabilized with beta-lactoglobulin alone. Emulsions prepared with the multilayer system of beta-lactoglobulin and sugar beet pectin were less stable than emulsions stabilized with beta-lactoglobulin alone despite the presence of ferulic acid in the sugar beet pectin. The lower oxidative stability of the emulsions with the sugar beet pectin could be due to its higher iron and copper concentrations which would produce oxidative stress that would overcome the antioxidant capacity of ferulic acid. These data suggest that the oxidative stability of oil-in-water emulsions containing omega-3 fatty acids could be improved by the use of multilayer emulsion systems containing pectins with low metal concentrations.

The Developmental Regulator SEEDSTICK Controls Structural and Mechanical Properties of the Arabidopsis Seed Coat

PubMed Central

Beauzamy, Léna; Caporali, Elisabetta; Koroney, Abdoul-Salam

2016-01-01

Although many transcription factors involved in cell wall morphogenesis have been identified and studied, it is still unknown how genetic and molecular regulation of cell wall biosynthesis is integrated into developmental programs. We demonstrate by molecular genetic studies that SEEDSTICK (STK), a transcription factor controlling ovule and seed integument identity, directly regulates PMEI6 and other genes involved in the biogenesis of the cellulose-pectin matrix of the cell wall. Based on atomic force microscopy, immunocytochemistry, and chemical analyses, we propose that structural modifications of the cell wall matrix in the stk mutant contribute to defects in mucilage release and seed germination under water-stress conditions. Our studies reveal a molecular network controlled by STK that regulates cell wall properties of the seed coat, demonstrating that developmental regulators controlling organ identity also coordinate specific aspects of cell wall characteristics. PMID:27624758

Mineral absorption by albino rats as affected by some types of dietary pectins with different degrees of esterification.

PubMed

el-Zoghbi, M; Sitohy, M Z

2001-04-01

Male albino rats were fed diets contained 6.85% mineral salts for 2 weeks (adaptation condition). Then they were fed the dietary pectin administered diet for 6 weeks to evaluate the effect of administration of pectin on the absorption of some monovalent, bivalent and heavy metals in the serum of rats. The experimental parameters included, monovalent minerals (K, Na), bivalent minerals (Zn, Cu, Ca, Fe), heavy metals (Pb, Cd), serum uric acid and serum creatinine. The obtained results indicated that the serum contents of monovalent minerals were negatively affected by pectin administration. The low degree of esterification of pectin was more effective on the absorption of bivalent minerals. Also, the rat serum levels of lead and cadmium were reduced by pectin administration. Serum total proteins were reduced by pectin administration. The level of rat serum of uric acid and creatinine fed different sources of pectin were within normal levels and were insignificantly lower than that recorded for control samples.

Pectin impacts cellulose fibre architecture and hydrogel mechanics in the absence of calcium.

PubMed

Lopez-Sanchez, Patricia; Martinez-Sanz, Marta; Bonilla, Mauricio R; Wang, Dongjie; Walsh, Cherie T; Gilbert, Elliot P; Stokes, Jason R; Gidley, Michael J

2016-11-20

Pectin is a major polysaccharide in many plant cell walls and recent advances indicate that its role in wall mechanics is more important than previously thought. In this work cellulose hydrogels were synthesised in pectin solutions, as a biomimetic tool to investigate the influence of pectin on cellulose assembly and hydrogel mechanical properties. Most of the pectin (60-80%) did not interact at the molecular level with cellulose, as judged by small angle scattering techniques (SAXS and SANS). Despite the lack of strong interactions with cellulose, this pectin fraction impacted the mechanical properties of the hydrogels through poroelastic effects. The other 20-40% of pectin (containing neutral sugar sidechains) was able to interact intimately with cellulose microfibrils at the point of assembly. These results support the need to revise the role of pectin in cell wall architecture and mechanics, and; furthermore they assist the design of cellulose-based products through controlling the viscoelasticity of the fluid phase. Copyright © 2016 Elsevier Ltd. All rights reserved.

Performance evaluation of pectin as ecofriendly corrosion inhibitor for X60 pipeline steel in acid medium: experimental and theoretical approaches.

PubMed

Umoren, Saviour A; Obot, Ime B; Madhankumar, A; Gasem, Zuhair M

2015-06-25

The corrosion inhibition effect of pectin (a biopolymer) for X60 pipeline steel in HCl medium was investigated using weight loss, electrochemical, water contact angle measurements, and scanning electron microscopy techniques. The results obtained show that pectin acts as a good corrosion inhibitor for X60 steel. Inhibition efficiency increased with increase in pectin concentration and temperature. Potentiodynamic polarization results reveal that pectin could be classified as a mixed-type corrosion inhibitor with predominant control of the cathodic reaction. The effective corrosion inhibition potential of pectin could be related to the adsorption of pectin molecules at the metal/solution interface which is found to accord with the Langmuir adsorption isotherm model and a protective film formation. Quantum chemical calculations provided insights into the active sites and reactivity parameters governing pectin activity as a good corrosion inhibitor for X60 steel. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhanced colonic delivery of ciclosporin A self-emulsifying drug delivery system encapsulated in coated minispheres.

PubMed

Keohane, Kieran; Rosa, Mónica; Coulter, Ivan S; Griffin, Brendan T

2016-01-01

Investigate the potential of coated minispheres (SmPill®) to enhance localized Ciclosporin A (CsA) delivery to the colon. CsA self-emulsifying drug delivery systems (SEDDS) were encapsulated into SmPill® minispheres. Varying degrees of coating thickness (low, medium and high) were applied using ethylcellulose and pectin (E:P) polymers. In vitro CsA release was evaluated in simulated gastric and intestinal media. Bioavailability of CsA in vivo following oral administration to pigs of SmPill® minispheres was compared to Neoral® po and Sandimmun® iv in a pig model. CsA concentrations in blood and intestinal tissue were determined by HPLC-UV. In vitro CsA release from coated minispheres decreased with increasing coating thickness. A linear relationship was observed between in vitro CsA release and in vivo bioavailability (r(2) = 0.98). CsA concentrations in the proximal, transverse and distal colon were significantly higher following administration of SmPill®, compared to Neoral® po and Sandimmun® iv (p < 0.05). Analysis of transverse colon tissue subsections also revealed significantly higher CsA concentrations in the mucosa and submucosa using SmPill® minispheres (p < 0.05). Modulating E:P coating thickness controls release of CsA from SmPill® minispheres. Coated minispheres limited CsA release in the small intestine and enhanced delivery and uptake in the colon. These findings demonstrate clinical advantages of an oral coated minisphere-enabled CsA formulation in the treatment of inflammatory conditions of the large intestine.

Characterization of gold kiwifruit pectin from fruit of different maturities and extraction methods.

PubMed

Yuliarti, Oni; Matia-Merino, Lara; Goh, Kelvin K T; Mawson, John; Williams, Martin A K; Brennan, Charles

2015-01-01

Studies on gold kiwifruit pectins are limited. In this work, the characterization of pectin isolated from two different stages of maturity of gold kiwifruit, namely early harvested fruit (EHF) and main harvested fruit (MHF) isolated by three methods (acid, water, enzymatic) was carried out. Pectins isolated from MHF were higher in galacturonic acid content (52-59% w/w) and weight-average molecular weights (Mw, 1.7-3.8 × 10(6)g/mol) compared with EHF pectins (29-49% w/w and 0.2-1.7 × 10(6)g/mol respectively). Enzymatic treatment gave the highest yield but lowest in Mw, viscosity and mechanical spectra for both maturities. The pectin of both maturities was classified as high-methoxyl pectin with the degree of esterification ranged from 82% to 90%. Water-extracted MHF pectin molecules had the highest RMS radius (182.7 nm) and Mw (3.75 × 10(6)g/mol). The water extraction method appeared to retain the native state of pectin molecules compared with acid and enzymatic extraction methods based on the Mw and viscosity data. Copyright © 2014 Elsevier Ltd. All rights reserved.

Extraction and characterisation of pomace pectin from gold kiwifruit (Actinidia chinensis).

PubMed

Yuliarti, Oni; Goh, Kelvin K T; Matia-Merino, Lara; Mawson, John; Brennan, Charles

2015-11-15

Gold kiwifruit pomace extracted using citric acid, water and enzyme (Celluclast 1.5L) were studied in terms of pectin yield, protein, ash, non-starch polysaccharide, galacturonic acid (GalA), neutral sugar composition, molar mass (Mw), viscosity and degree of branching. Water-extracted pectin was considered closest to its native form. Enzyme extracted pectin showed the highest yield (∼ 4.5%w/w) as compared with the acid and water extraction methods (∼ 3.6-3.8%w/w). Pectin obtained from different extraction methods showed different degree of branching. The Mw and root mean square (RMS) radius varied with the extraction methods with values of 8.4 × 10(5) g/mol and 92 nm, 8.5 × 10(5)g/mol and 102 nm, 6.7 × 10(5) g/mol and 52 nm for acid, water and enzymatic extraction methods, respectively. Similar trend was observed for pectin viscosity, with water-extracted pectin giving a slightly higher viscosity followed by acid and enzyme-extracted pectin. This study showed that gold kiwifruit pomace pectin has potential application in food products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extraction of green labeled pectins and pectic oligosaccharides from plant byproducts.

PubMed

Zykwinska, Agata; Boiffard, Marie-Hélène; Kontkanen, Hanna; Buchert, Johanna; Thibault, Jean-François; Bonnin, Estelle

2008-10-08

Green labeled pectins were extracted by an environmentally friendly way using proteases and cellulases being able to act on proteins and cellulose present in cell walls. Pectins were isolated from different plant byproducts, i.e., chicory roots, citrus peel, cauliflower florets and leaves, endive, and sugar beet pulps. Enzymatic extraction was performed at 50 degrees C for 4 h, in order to fulfill the conditions required for microbiological safety of extracted products. High methoxy (HM) pectins of high molar mass were extracted with three different enzyme mixtures. These pectins were subsequently demethylated with two pectin methyl esterases (PMEs), either the fungal PME from Aspergillus aculeatus or the orange PME. It was further demonstrated that high molar mass low methoxy (LM) pectins could also be extracted directly from cell walls by adding the fungal PME to the mixture of protease and cellulase. Moreover, health benefit pectic oligosaccharides, the so-called modified hairy regions, were obtained after enzymatic treatment of the residue recovered after pectin extraction. The enzymatic method demonstrates that it is possible to convert vegetable byproducts into high-added value compounds, such as pectins and pectic oligosaccharides, and thus considerably reduce the amount of these residues generated by food industries.

Combined enzymatic and colorimetric method for determining the uronic acid and methylester content of pectin: Application to tomato products.

PubMed

Anthon, Gordon E; Barrett, Diane M

2008-09-01

A simple procedure for determining the galacturonic acid and methanol contents of soluble and insoluble pectins, relying on enzymatic pectin hydrolysis and colorimetric quantification, is described. Pectin samples are incubated with a commercial pectinase preparation, Viscozyme, then the galacturonic acid content of the hydrolyzed pectin is quantified colorimetrically using a modification of the Cu reduction procedure originally described by Avigad and Milner. This modification, substituting the commonly used Folin-Ciocalteau reagent for the arsenic containing Nelson reagent, gives a response that is linear, sensitive, and selective for uronic acids over neutral sugars. This method also avoids the use of concentrated acids needed for the commonly used m-phenylphenol method. Methanol, released by the action of the pectin methylesterase found in the Viscozyme, is quantified using alcohol oxidase and Purpald. This combined enzymatic and colorimetric procedure correctly determined the galacturonic acid and methanol content of purified, soluble citrus pectin. Application of the procedure to water insoluble pectins was evaluated with water insoluble material from apples and oranges. In both cases good agreement was obtained between this method and commonly used methods based on chemical pectin hydrolysis. Good agreement between these procedures was also found in the analysis of both soluble and insoluble pectins from several tomato products. Copyright © 2008 Elsevier Ltd. All rights reserved.

Palmyra palm (Borassus aethiopum Mart.) fruits: novel raw materials for the pectin industry.

PubMed

Assoi, Sylvie; Konan, Koffi; Agbo, Georges N; Dodo, Hortense; Holser, Ron; Wicker, Louise

2017-05-01

Preventing post-harvest waste of Palmyra palm (Borassus aethiopum Mart.) fruits is possible by recovery of pectin as a value-added ingredient. Extraction conditions on yield and functionality of Palmyra palm pectin was determined at different temperatures and pH values with 30 min extraction time. Palmyra palm fruits contain more than 650 g kg -1 galacturonic acid and produce soft gels with sucrose in acidic media despite a high degree of acetylation (∼5%). Mechanical deformation of pectin gel was similar when extracted at pH 2.5 and 70 °C or under natural pH at room temperature or 70 °C. Pectins isolated at pH 7 exhibited comparable gel softness (G'/G″) with commercial pectin. Palm pectins also showed emulsifying activity greater than 50%, attributed to high protein content of 8 g 100 g -1 . For pectins extracted at pH near 5.2-5.5, molar mass ranged from 3.00 to 3.38 × 10 5 g mol -1 ; intrinsic viscosity ranged from 218 to 297 mL g -1 ; arabinose was the main neutral sugar; ζ-potential ranged from -23 to -25 mV. Palm fruit offers an inexpensive raw material to extract pectin in environmentally friendly and economical way and yield a pectin with unique gelling, viscosifying and emulsifying properties. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

[Influence of various pectins on production of staphylococcal enterotoxins types A and B].

PubMed

Fluer, F S; Men'shikov, D D; Lazareva, E B; Prokhorov, V Ia; Vesnin, A V

2007-01-01

Experimental in vitro study of influence of 2% solution of pectins (red beet, apple, citrus, manufactured by "Vitaline" company, citrus high- and low-etherified pectins, manufactured by "Hercules" company, Unipectine OB 700, and biologically active supplement "Pecto") on growth of staphylococci and production by them of type A and B enterotoxins was performed. It was shown that red beet, citrus high- and low-etherified pectins, as well as biologically active supplement "Pecto" render bactericidal effect on staphylococci and inhibit synthesis of types A and B staphylococcal enterotoxins. Citrus pectin "Vitaline" and Unipectine OB 700 don't have such influence. The most effective pectins, which were able to inhibit synthesis of types A and B staphylococcal enterotoxins, were red beet, apple, and citrus low-etherified pectins as well as biologically active supplement "Pecto".

Importance of solid lipid nanoparticles (SLN) in various administration routes and future perspectives

PubMed Central

Üner, Melike; Yener, Gülgün

2007-01-01

Solid lipid nanoparticles (SLN) have been reported to be an alternative system to emulsions, liposomes, microparticles and their polymeric counterparts for various application routes since the early 1990s due to their advantages. Various research groups have also increasingly focused on improving their stability in body fluids after administration by coating of particles with hydrophilic molecules such as poly(ethylene)glycol (PEG) derivatives. Altering surface characteristics by coating SLN with hydrophilic molecules improves plasma stability and biodistribution, and subsequent bioavailability of drugs entrapped. Their storage stability is also increased. This paper basicly reviews types of SLN, principles of drug loading and models of drug incorporation. The influence of PEG coating on particle size and surface characteristics is discussed followed by alteration in pharmacokinetics and bioavailability of drugs in order to target the site of action via SLN. The future direction of research and clinical implications of SLN is also considered. PMID:18019829

Rhamnogalacturonan I containing homogalacturonan inhibits colon cancer cell proliferation by decreasing ICAM1 expression

USDA-ARS?s Scientific Manuscript database

Pectin modified with pH, heat or enzymes, has previously been shown to exhibit anti-cancer activity. However, the structural requirements for bioactive modified pectins have rarely been addressed. In this study several pectin extracts representing different structural components of pectin were asses...

21 CFR 582.1775 - Sodium pectinate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium pectinate. 582.1775 Section 582.1775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1775 Sodium pectinate. (a) Product. Sodium pectinate. (b) Conditions of use. This substance...

21 CFR 582.1775 - Sodium pectinate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium pectinate. 582.1775 Section 582.1775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1775 Sodium pectinate. (a) Product. Sodium pectinate. (b) Conditions of use. This substance...

21 CFR 582.1775 - Sodium pectinate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium pectinate. 582.1775 Section 582.1775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1775 Sodium pectinate. (a) Product. Sodium pectinate. (b) Conditions of use. This substance...

21 CFR 582.1775 - Sodium pectinate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium pectinate. 582.1775 Section 582.1775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1775 Sodium pectinate. (a) Product. Sodium pectinate. (b) Conditions of use. This substance...

21 CFR 582.1775 - Sodium pectinate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium pectinate. 582.1775 Section 582.1775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1775 Sodium pectinate. (a) Product. Sodium pectinate. (b) Conditions of use. This substance...

Effects of Accelerated Storage on the Quality of Kenaf Seed Oil in Chitosan-Coated High Methoxyl Pectin-Alginate Microcapsules.

PubMed

Leong, Mei-Huan; Tan, Chin-Ping; Nyam, Kar-Lin

2016-10-01

The objective of this research was to study the oxidative stability and antioxidant properties of microencapsulated kenaf (Hibiscus cannabinus L.) seed oil (MKSO) produced by co-extrusion technology upon accelerated storage. The combination of sodium alginate, high methoxyl pectin, and chitosan were used as shell materials. The oxidative stability of the kenaf seed oil was determined by iodine value, peroxide value, p-Anisidine value, total oxidation (TOTOX), thiobarbituric acid reactive substances assay, and free fatty acid content. Total phenolic content, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical-scavenging assay and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay were used to examine the antioxidant properties of oils. Oxidative stability tests showed that bulk kenaf seed oil (BKSO) was oxidized significantly higher (P < 0.05) than MKSO. The total increment of TOTOX value of BKSO was 165.93% significantly higher (P < 0.05) than MKSO. Co-extrusion technology has shown to be able to protect kenaf seed oil against lipid oxidation and delay the degradation of natural antioxidants that present in oil during storage. © 2016 Institute of Food Technologists®.

Microwave-assisted extraction of pectin from cocoa peel

NASA Astrophysics Data System (ADS)

Sarah, M.; Hanum, F.; Rizky, M.; Hisham, M. F.

2018-02-01

Pectin is a polymer of d-galacturonate acids linked by β-1,4 glycosidic bond. This study isolates pectin from cocoa peel (Theobroma cacao) using citric acid as solvent by microwave-assisted extraction method. Cocoa peels (moisture content of 10%) with citric acid solution (pH of 1.5) irradiated by microwave energy at various microwave power (180, 300, 450 and 600 W) for 10, 15, 20, 25 and 30 minutes respectively. Pectin obtained from this study was collected and filtrated by adding 96% ethanol to precipitate the pectin. The best results obtained from extraction process using microwave power of 180 Watt for 30 minutes. This combination of power and time yielded 42.3% pectin with moisture content, ash content, weight equivalent, methoxyl content and galacturonate levels were 8.08%, 5%, 833.33 mg, 6.51% and 58,08%, respectively. The result finding suggested that microwave-assisted extraction method has a great potency on the commercial pectin production.

Membrane fusion between baculovirus budded virus-enveloped particles and giant liposomes generated using a droplet-transfer method for the incorporation of recombinant membrane proteins.

PubMed

Nishigami, Misako; Mori, Takaaki; Tomita, Masahiro; Takiguchi, Kingo; Tsumoto, Kanta

2017-07-01

Giant proteoliposomes are generally useful as artificial cell membranes in biochemical and biophysical studies, and various procedures for their preparation have been reported. We present here a novel preparation technique that involves the combination of i) cell-sized lipid vesicles (giant unilamellar vesicles, GUVs) that are generated using the droplet-transfer method, where lipid monolayer-coated water-in-oil microemulsion droplets interact with oil/water interfaces to form enclosed bilayer vesicles, and ii) budded viruses (BVs) of baculovirus (Autographa californica nucleopolyhedrovirus) that express recombinant transmembrane proteins on their envelopes. GP64, a fusogenic glycoprotein on viral envelopes, is activated by weak acids and is thought to cause membrane fusion with liposomes. Using confocal laser scanning microscopy (CLSM), we observed that the single giant liposomes fused with octadecyl rhodamine B chloride (R18)-labeled wild-type BV envelopes with moderate leakage of entrapped soluble compounds (calcein), and the fusion profile depended on the pH of the exterior solution: membrane fusion occurred at pH ∼4-5. We further demonstrated that recombinant transmembrane proteins, a red fluorescent protein (RFP)-tagged GPCR (corticotropin-releasing hormone receptor 1, CRHR1) and envelope protein GP64 could be partly incorporated into membranes of the individual giant liposomes with a reduction of the pH value, though there were also some immobile fluorescent spots observed on their circumferences. This combination may be useful for preparing giant proteoliposomes containing the desired membranes and inner phases. Copyright © 2017 Elsevier B.V. All rights reserved.

Mannose-coated gadolinium liposomes for improved magnetic resonance imaging in acute pancreatitis.

PubMed

Tian, Bing; Liu, Ri; Chen, Shiyue; Chen, Luguang; Liu, Fang; Jia, Guorong; Dong, Yinmei; Li, Jing; Chen, Huaiwen; Lu, Jianping

2017-01-01

Acute pancreatitis (AP) is an acute inflammatory condition of the pancreas. The symptoms, treatment, and prognosis of mild and severe AP are different, and severe AP is a potentially life-threatening disease with a high incidence of complications and high mortality rate. Thus, it is urgent to develop an effective approach to reliably discriminate between mild and severe AP. We have developed novel gadolinium-diethylenetriaminepentaacetic (Gd-DTPA)-loaded mannosylated liposomes (named thereafter M-Gd-NL) that preferably target macrophages in AP. The targeting ability of M-Gd-NL toward macrophages in AP and its ability to discriminate between mild and severe AP were evaluated. The liposomes were of desired particle size (~100 nm), Gd-DTPA encapsulation efficiency (~85%), and stability. M-Gd-NL and non-targeted Gd-DTPA-loaded liposomes (Gd-NL) exhibited increased relaxivity compared with Gd-DTPA. Compared with Gd-NL and Gd-DTPA, M-Gd-NL showed increased uptake in macrophages, resulting in increased T 1 imaging ability both in vitro (macrophage cell line) and in vivo (severe AP model). Importantly, M-Gd-NL had the ability to discriminate between mild and severe AP, as reflected by a significantly higher T 1 magnetic resonance imaging signal in severe AP than in mild AP. M-Gd-NL did not show severe organ toxicity in rats. Our data suggest that M-Gd-NL had enhanced magnetic resonance imaging ability by targeting macrophages in AP and good ability to discriminate between mild and severe AP. We believe that M-Gd-NL could shed new light on the diagnosis of AP in the near future.

Wetting properties of phospholipid dispersion on tunable hydrophobic SiO2-glass plates.

PubMed

Alexandrova, Lidia; Karakashev, Stoyan I; Grigorov, L; Phan, Chi M; Smoukov, Stoyan K

2015-06-01

We study the wetting properties of very small droplets of salty aqueous suspensions of unilamellar liposomes of DMPC (dimyristoylphosphatidylcholine), situated on SiO2-glass surfaces with different levels of hydrophobicity. We evaluated two different measures of hydrophobicity of solid surfaces - receding contact angles and the thickness of wetting films trapped between an air bubble and the solid surface at different levels of hydrophobicity. We established a good correlation between methods which differ significantly in measurement difficulty and experimental setup. We also reveal details of the mechanism of wetting of different surfaces by the DMPC liposome suspension. Hydrophilic surfaces with water contact angles in the range of 0° to 35° are readily hydrophobized by the liposomes and only showed corresponding contact angles in the range 27°-43°. For same range of surface hydrophobicities, there was a clear reduction of the thickness of the wetting films between the surface and a bubble, reaching a minimum in the 35°-40° range. At higher levels of hydrophobicity both pure water and the liposome suspension show similar contact angles, and the thickness of wetting films between a bubble and those surfaces increases in parallel. Our analysis showed that the only force able to stabilize the film under these experimental conditions is steric repulsion. The latter suggests that nanobubbles adsorbed on hydrophobic parts of the surface, and coated with a DMPC layer, may be the cause of the 40-70 nm thickness of wetting films we observe. Copyright © 2014 Elsevier B.V. All rights reserved.

Nanostructural Characterization of Modified Homogalacturonan with Pectin Methylesterase from Jelly Fig (Ficus awkeotsang Makino) Achenes and Modeling of Enzyme Mode of Action

USDA-ARS?s Scientific Manuscript database

1. Justification: Pectin is a major hydrocolloid used in various food, cosmetics, and medicine pharmaceutical products. The relative amount of unmethylesterified galacturonic acid (GalA)residues and their distribution are key determinants of pectin functionality. Pectin methylesterase (PME) modifies...

Yield, Esterification Degree and Molecular Weight Evaluation of Pectins Isolated from Orange and Grapefruit Peels under Different Conditions

PubMed Central

Sayah, Mohamed Yassine; Chabir, Rachida; Benyahia, Hamid; Rodi Kandri, Youssef; Ouazzani Chahdi, Fouad; Touzani, Hanan; Errachidi, Faouzi

2016-01-01

Orange (Citrus sinensis) and grapefruit (Citrus paradise) peels were used as a source of pectin, which was extracted under different conditions. The peels are used under two states: fresh and residual (after essential oil extraction). Organic acid (citric acid) and mineral acid (sulfuric acid) were used in the pectin extraction. The aim of this study is the evaluation the effect of extraction conditions on pectin yield, degree of esterification “DE” and on molecular weight “Mw”. Results showed that the pectin yield was higher using the residual peels. Moreover, both peels allow the obtainment of a high methoxyl pectin with DE >50%. The molecular weight was calculated using Mark-Houwink-Sakurada equation which describes its relationship with intrinsic viscosity. This later was determined using four equations; Huggins equation, kramer, Schulz-Blaschke and Martin equation. The molecular weight varied from 1.538 x1005 to 2.47x1005 g/mol for grapefruit pectin and from 1.639 x1005 to 2.471 x1005 g/mol for orange pectin. PMID:27644093

Dietary fibre components and pectin chemical features of peels during ripening in banana and plantain varieties.

PubMed

Happi Emaga, Thomas; Robert, Christelle; Ronkart, Sébastien N; Wathelet, Bernard; Paquot, Michel

2008-07-01

The effects of the ripeness stage of banana (Musa AAA) and plantain (Musa AAB) peels on neutral detergent fibre, acid detergent fibre, cellulose, hemicelluloses, lignin, pectin contents, and pectin chemical features were studied. Plantain peels contained a higher amount of lignin but had a lower hemicellulose content than banana peels. A sequential extraction of pectins showed that acid extraction was the most efficient to isolate banana peel pectins, whereas an ammonium oxalate extraction was more appropriate for plantain peels. In all the stages of maturation, the pectin content in banana peels was higher compared to plantain peels. Moreover, the galacturonic acid and methoxy group contents in banana peels were higher than in plantain peels. The average molecular weights of the extracted pectins were in the range of 132.6-573.8 kDa and were not dependant on peel variety, while the stage of maturation did not affect the dietary fibre yields and the composition in pectic polysaccharides in a consistent manner. This study has showed that banana peels are a potential source of dietary fibres and pectins.

Formation of Polyelectrolyte Complex Colloid Particles between Chitosan and Pectin with Different Degree of Esterification

NASA Astrophysics Data System (ADS)

Wang, Hui; Sun, Hongyuan; He, Jieyu

2017-12-01

The effects of degree of esterification, pectin/chitosan ratio and pH on the formation of polyelectrolyte complex colloid particles between chitosan (CS) and pectin (PE) were investigated. Low methoxyl pectin (LPE) was achieved by de-esterifying high methoxyl pectin (HPE) with pectin methyl esterase. Turbidity titration and colorimetric method was used to determine the stability of complex colloid particles. The structure and morphology of complex particles were characterized by FTIR and TEM. When pectin solution was dropped into chitosan solution, complex colloidal dispersion was stable as PE/CS mass ratio was no more than 3:2. Colloidal particles of HPE-CS complex coagulated at larger ratio of PE/CS than LPE-CS. The maximum complex occurred at pH 6.1 for HPE-CS and pH 5.7 for LPE-CS, and decreasing pH leaded to the dissociation of complex particles. Electrostatic interactions between carboxyl groups on pectin and amino groups on chitosan were confirmed by FTIR. Colloidal particle sizes ranged from about 100 nm to 400 nm with spherical shape.

Descriptive parameters for revealing substitution patterns of sugar beet pectins using pectolytic enzymes.

PubMed

Remoroza, C; Buchholt, H C; Gruppen, H; Schols, H A

2014-01-30

Enzymatic fingerprinting was applied to sugar beet pectins (SBPs) modified by either plant or fungal pectin methyl esterases and alkali catalyzed de-esterification to reveal the ester distributions over the pectin backbone. A simultaneous pectin lyase (PL) treatment to the commonly used endo-polygalacturonase (endo-PG) degradation showed to be effective in degrading both high and low methylesterified and/or acetylated homogalaturonan regions of SBP simultaneously. Using LC-HILIC-MS/ELSD, we studied in detail all the diagnostic oligomers present, enabling us to discriminate between differently prepared sugar beet pectins having various levels of methylesterification and acetylation. Furthermore, distinction between commercially extracted and de-esterified sugar beet pectin having different patterns of substitution was achieved by using novel descriptive pectin parameters. In addition to DBabs approach for nonmethylesterified sequences degradable by endo-PG, the "degree of hydrolysis" (DHPG) representing all partially saturated methylesterified and/or acetylated galacturonic acid (GalA) moieties was introduced as a new parameter. Consequently, the description DHPL has been introduced to quantify all esterified unsaturated GalA oligomers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Decreasing methylation of pectin caused by nitric oxide leads to higher aluminium binding in cell walls and greater aluminium sensitivity of wheat roots

PubMed Central

Sun, Chengliang; Lu, Lingli; Yu, Yan; Liu, Lijuan; Hu, Yan; Ye, Yiquan; Jin, Chongwei; Lin, Xianyong

2016-01-01

Nitric oxide (NO) is an important bioactive molecule involved in cell wall metabolism, which has been recognized as a major target of aluminium (Al) toxicity. We have investigated the effects of Al-induced NO production on cell wall composition and the subsequent Al-binding capacity in roots of an Al-sensitive cultivar of wheat (Triticum aestivum L. cv. Yang-5). We found that Al exposure induced NO accumulation in the root tips. Eliminating NO production with an NO scavenger (cPTIO) significantly alleviated the Al-induced inhibition of root growth and thus reduced Al accumulation. Elimination of NO, however, did not significantly affect malate efflux or rhizosphere pH changes under Al exposure. Levels of cell wall polysaccharides (pectin, hemicelluloses 1, and hemicelluloses 2) and pectin methylesterase activity, as well as pectin demethylation in the root apex, significantly increased under Al treatment. Exogenous cPTIO application significantly decreased pectin methylesterase activity and increased the degree of methylation of pectin in the root cell wall, thus decreasing the Al-binding capacity of pectin. These results suggest that the Al-induced enhanced production of NO decreases cell wall pectin methylation, thus increasing the Al-binding capacity of pectin and negatively regulating Al tolerance in wheat. PMID:26663393

Chemical modification of citrus pectin: Structural, physical and rheologial implications.

PubMed

Fracasso, Aline Francielle; Perussello, Camila Augusto; Carpiné, Danielle; Petkowicz, Carmen Lúcia de Oliveira; Haminiuk, Charles Windson Isidoro

2018-04-01

The present study aimed to investigate the physical, structural and rheological modifications caused by the chemical modification process of citrus pectin. Therefore, three commercial citrus pectins with different degree of esterification were chemically modified by sequential alkali and acidic hydrolytic process to produce modified citrus pectins (MCP) with special properties. The molar mass (M w ), degree of esterification (DE), monosaccharide composition, 13 C NMR spectra, homogeneity, morphology (SEM) and rheological behavior of both native and modified citrus pectins (MCP) were investigated. The chemical modification reduced the acid uronic content (up to 28.3%) and molar mass (up to 29.98%), however, showed little influence on the degree of esterification of native pectins. Modified citrus pectins presented higher amounts of neutral monosaccharides, mainly galactose, arabinose and rhamnose, typical of the Ramnogalacturonana-I (RG-I) region. Rheological tests indicated that the native and modified citrus pectins presented pseudoplastic behavior, however, the MCP samples were less viscous, compared to the native ones. Modified samples presented better dissolution in water and less strong gels, with good stability during oscillatory shearing at 25°C. This study aims to better understand the implications that chemical modifications may impose on the structure of citrus pectins. Copyright © 2017 Elsevier B.V. All rights reserved.

Viscoelastic properties of soy protein isolate - pectin blends: Richer than those of a simple composite material.

PubMed

Dekkers, Birgit L; Boom, Remko M; van der Goot, Atze Jan

2018-05-01

Concentrated soy protein isolate (SPI) - pectin blends acquire fibrous textures by shear-induced structuring while heating. The objective of this study was to determine the viscoelastic properties of concentrated SPI-pectin blends under similar conditions as during shear-induced structuring, and after cooling. A closed cavity rheometer was used to measure these properties under these conditions. At 140 °C, SPI and pectin had both a lower G* than the blend of the two and also showed a different behavior in time. Hence, the viscoelastic properties of the blend are richer than those of a simple composite material with stable physical phase properties. In addition, the G' pectin was much lower compared with the G' SPI and G' SPI-pectin upon cooling, confirming that pectin formed a weak dispersed phase. The results can be explained by considering that the viscoelastic properties of the blend are influenced by thermal degradation of the pectin phase. This degradation leads to: i) release of galacturonic acid, ii) lowering of the pH, and iii) water redistribution from the SPI towards the pectin phase. The relative importance of those effects are evaluated. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of degree of esterification of pectin and calcium amount on drug release from pectin-based matrix tablets.

PubMed

Sungthongjeen, Srisagul; Sriamornsak, Pornsak; Pitaksuteepong, Tasana; Somsiri, Atawit; Puttipipatkhachorn, Satit

2004-02-12

The aim of this work was to assess the effect of 2 formulation variables, the pectin type (with different degrees of esterification [DEs]) and the amount of calcium, on drug release from pectin-based matrix tablets. Pectin matrix tablets were prepared by blending indomethacin (a model drug), pectin powder, and various amounts of calcium acetate and then tableting by automatic hydraulic press machine. Differential scanning calorimetry, powder x-ray diffraction, and Fourier transformed-infrared spectroscopy studies of the compressed tablets revealed no drug-polymer interaction and the existence of drug with low crystallinity. The in-vitro release studies in phosphate buffer (United States Pharmacopeia) and tris buffer indicated that the lower the DE, the greater the time for 50% of drug release (T50). This finding is probably because of the increased binding capacity of pectin to calcium. However, when the calcium was excluded, the pectins with different DEs showed similar release pattern with insignificant difference of T50. When the amount of calcium acetate was increased from 0 to 12 mg/tablet, the drug release was significantly slower. However, a large amount of added calcium (ie, 24 mg/tablet) produced greater drug release because of the partial disintegration of tablets. The results were more pronounced in phosphate buffer, where the phosphate ions induced the precipitation of calcium phosphate. In conclusion, both pectin type and added calcium affect the drug release from the pectin-based matrix tablets.

Pectin-cysteine conjugate: synthesis and in-vitro evaluation of its potential for drug delivery.

PubMed

Majzoob, Sayeh; Atyabi, Fatemeh; Dorkoosh, Farid; Kafedjiiski, Krum; Loretz, Brigitta; Bernkop-Schnürch, Andreas

2006-12-01

This study was aimed at improving certain properties of pectin by introduction of thiol moieties on the polymer. Thiolated pectin was synthesized by covalent attachment of cysteine. Pectin-cysteine conjugate was evaluated for its ability to be degraded by pectinolytic enzyme. The toxicity profile of the thiolated polymer in Caco-2-cells, its permeation enhancing effect and its mucoadhesive and swelling properties were studied. Moreover insulin-loaded hydrogel beads of the new polymer were examined for their stability in simulated gastrointestinal conditions and their drug release profile. The new polymer displayed 892.27 +/- 68.68 micromol thiol groups immobilized per g polymer, and proved to have retained its biodegradability, upon addition of Pectinex Ultra SPL in-vitro, determined by viscosity measurements and titration method. Pectin-cysteine showed no severe toxicity in Caco-2 cells, as tested by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Moreover, the synthesized polymer exhibited a relative permeation enhancement ratio of 1.61 for sodium fluorescein, compared to unmodified pectin. Pectin-cysteine conjugate exhibited approximately 5-fold increased in in-vitro adhesion duration and significantly improved cohesive properties. Zinc pectin-cysteine beads showed improved stability in simulated gastrointestinal media; however, insulin release from these beads followed the same profile as unmodified zinc pectinate beads. Due to favourable safety and biodegradability profile, and improved cohesive and permeation-enhancing properties, pectin-cysteine might be a promising excipient in various transmucosal drug delivery systems.

Effects of membrane-filtered soy hull pectin and pre-emulsified fiber/oil on chemical and technological properties of low fat and low salt meat emulsions.

PubMed

Kim, Hyun-Wook; Lee, Yong Jae; Kim, Yuan H Brad

2016-06-01

The objectives of this study were to determine efficacy of a membrane filtration in soy hull pectin purification and evaluate combined effects of soy hull pectin and pre-emulsified fiber/oil (PE) on chemical composition and technological properties of low fat and low salt meat emulsions. Soy hull pectin was purified through two different methods (alcohol-washed (ASP) and membrane-filtered (MSP)). Insoluble soy hull residues after pectin extraction were incorporated with sunflower oil and water for the PE preparation. Meat emulsion was formulated with 58 % pork, 20 % ice, 20 % pork backfat, and 2 % NaCl as control. A total of six low fat and low salt meat emulsions (1 % NaCl and 10 % backfat) was manufactured with 1 % pectin (with/without ASP or MSP) and 10 % PE (with/without). The pectin content of ASP and MSP was 0.84 and 0.64 g L-galacturonic acid/g dry sample, respectively. The inclusion of soy hull pectin caused similar results on chemical composition, color, cooking loss, and texture of the meat emulsions, regardless of the purification method. In addition, positive impacts of the combined treatments with soy hull pectin and PE compared to single treatments on cooking loss and texture of the meat emulsions were observed. Results suggest that membrane filtration could be an effective alternative method to purify pectin, instead of alcohol-washing, and both soluble pectin and insoluble fiber from soy hulls could be used as a functional non-meat ingredient to manufacture various low fat and low salt meat products.

Effects of Dietary Fibre (Pectin) and/or Increased Protein (Casein or Pea) on Satiety, Body Weight, Adiposity and Caecal Fermentation in High Fat Diet-Induced Obese Rats.

PubMed

Adam, Clare L; Gratz, Silvia W; Peinado, Diana I; Thomson, Lynn M; Garden, Karen E; Williams, Patricia A; Richardson, Anthony J; Ross, Alexander W

2016-01-01

Dietary constituents that suppress appetite, such as dietary fibre and protein, may aid weight loss in obesity. The soluble fermentable dietary fibre pectin promotes satiety and decreases adiposity in diet-induced obese rats but effects of increased protein are unknown. Adult diet-induced obese rats reared on high fat diet (45% energy from fat) were given experimental diets ad libitum for 4 weeks (n = 8/group): high fat control, high fat with high protein (40% energy) as casein or pea protein, or these diets with added 10% w/w pectin. Dietary pectin, but not high protein, decreased food intake by 23% and induced 23% body fat loss, leading to 12% lower final body weight and 44% lower total body fat mass than controls. Plasma concentrations of satiety hormones PYY and total GLP-1 were increased by dietary pectin (168% and 151%, respectively) but not by high protein. Plasma leptin was decreased by 62% on pectin diets and 38% on high pea (but not casein) protein, while plasma insulin was decreased by 44% on pectin, 38% on high pea and 18% on high casein protein diets. Caecal weight and short-chain fatty acid concentrations in the caecum were increased in pectin-fed and high pea protein groups: caecal succinate was increased by pectin (900%), acetate and propionate by pectin (123% and 118%, respectively) and pea protein (147% and 144%, respectively), and butyrate only by pea protein (309%). Caecal branched-chain fatty acid concentrations were decreased by pectin (down 78%) but increased by pea protein (164%). Therefore, the soluble fermentable fibre pectin appeared more effective than high protein for increasing satiety and decreasing caloric intake and adiposity while on high fat diet, and produced a fermentation environment more likely to promote hindgut health. Altogether these data indicate that high fibre may be better than high protein for weight (fat) loss in obesity.

Genotypic differences in Al resistance and the role of cell-wall pectin in Al exclusion from the root apex in Fagopyrum tataricum

PubMed Central

Yang, Jian Li; Zhu, Xiao Fang; Zheng, Cheng; Zhang, Yue Jiao; Zheng, Shao Jian

2011-01-01

Background and Aims Aluminium (Al) toxicity is one of the factors limiting crop production on acid soils. However, genotypic differences exist among plant species or cultivars in response to Al toxicity. This study aims to investigate genotypic differences among eight cultivars of tatary buckwheat (Fagopyrum tataricum) for Al resistance and explore the possible mechanisms of Al resistance. Methods Al resistance was evaluated based on relative root elongation (root elongation with Al/root elongation without Al). Root apex Al content, pectin content and exudation of root organic acids were determined and compared. Key Results Genotypic differences among the eight cultivars were correlated with exclusion of Al from the root apex. However, there was a lack of correlation between Al exclusion and Al-induced oxalate secretion. Interestingly, cell-wall pectin content of the root apex was generally lower in Al-resistant cultivars than in Al-sensitive cultivars. Although we were unable to establish a significant correlation between Al exclusion and pectin content among the eight cultivars, a strong correlation could be established among six cultivars, in which the pectin content in the most Al-resistant cultivar ‘Chuan’ was significantly lower than that in the most Al-sensitive cultivar ‘Liuku2’. Furthermore, root apex cell-wall pectin methylesterase activity (PME) was similar in ‘Chuan’ and ‘Liuku2’ in the absence of Al, but Al treatment resulted in increased PME activity in ‘Liuku2’ compared with ‘Chuan’. Immunolocalization of pectins also showed that the two cultivars had similar amounts of either low-methyl-ester pectins or high-methyl-ester pectins in the absence of Al, but Al treatment resulted in a more significant increase of low-methyl-ester pectins and decrease of high-methyl-ester pectins in ‘Liuku2’. Conclusions Cell-wall pectin content may contribute, at least in part, to differential Al resistance among tatary buckwheat cultivars. PMID:21183454

Effects of Dietary Fibre (Pectin) and/or Increased Protein (Casein or Pea) on Satiety, Body Weight, Adiposity and Caecal Fermentation in High Fat Diet-Induced Obese Rats

PubMed Central

Adam, Clare L.; Gratz, Silvia W.; Peinado, Diana I.; Thomson, Lynn M.; Garden, Karen E.; Williams, Patricia A.; Richardson, Anthony J.; Ross, Alexander W.

2016-01-01

Dietary constituents that suppress appetite, such as dietary fibre and protein, may aid weight loss in obesity. The soluble fermentable dietary fibre pectin promotes satiety and decreases adiposity in diet-induced obese rats but effects of increased protein are unknown. Adult diet-induced obese rats reared on high fat diet (45% energy from fat) were given experimental diets ad libitum for 4 weeks (n = 8/group): high fat control, high fat with high protein (40% energy) as casein or pea protein, or these diets with added 10% w/w pectin. Dietary pectin, but not high protein, decreased food intake by 23% and induced 23% body fat loss, leading to 12% lower final body weight and 44% lower total body fat mass than controls. Plasma concentrations of satiety hormones PYY and total GLP-1 were increased by dietary pectin (168% and 151%, respectively) but not by high protein. Plasma leptin was decreased by 62% on pectin diets and 38% on high pea (but not casein) protein, while plasma insulin was decreased by 44% on pectin, 38% on high pea and 18% on high casein protein diets. Caecal weight and short-chain fatty acid concentrations in the caecum were increased in pectin-fed and high pea protein groups: caecal succinate was increased by pectin (900%), acetate and propionate by pectin (123% and 118%, respectively) and pea protein (147% and 144%, respectively), and butyrate only by pea protein (309%). Caecal branched-chain fatty acid concentrations were decreased by pectin (down 78%) but increased by pea protein (164%). Therefore, the soluble fermentable fibre pectin appeared more effective than high protein for increasing satiety and decreasing caloric intake and adiposity while on high fat diet, and produced a fermentation environment more likely to promote hindgut health. Altogether these data indicate that high fibre may be better than high protein for weight (fat) loss in obesity. PMID:27224646

Influence of different functional ingredients on physical properties, rheology, tribology, and oral perceptions of no fat stirred yoghurt.

PubMed

Ng, Sophia Bao Xian; Nguyen, Phuong T M; Bhandari, Bhesh; Prakash, Sangeeta

2018-06-01

Effects of adding four functional ingredients: inulin, pectin, galacto-oligosaccharides (GOS), and beta glucan on physical, rheology, tribology, and sensory characteristics of skim (0.1% fat) stirred yoghurt were studied. Three levels of each ingredient were chosen: inulin (7, 8, and 9%), pectin (0.2, 0.25, and 0.3%), GOS (9.1, 11.3, and 13.6%), and beta glucan (0.1, 0.2, and 0.3%). Among the investigated ingredients, inulin and GOS appeared to be preferable choices due to their ability to both reduce syneresis and slightly increase sample lubrication while maintaining texture, rheology, and sensory characteristics of skim yoghurt. Pectin and beta glucan, conversely, increased viscosity and gel strength, slightly increased sample lubrication for the skim yoghurt but created large particles (i.e., greater than 100 μm) in the product body. This led to the increase in lumpiness and residual coating while reducing smoothness and creaminess of the sample. The observed tribology behaviors of the stirred yoghurts were similar to the previous study of pot-set yoghurt whose friction curves comprised four friction zones (Nguyen, Kravchuk, Bhandari, and Prakash). The sensory characteristics of six selected samples for various texture and mouthfeel attributes obtained from a trained panel were in agreement with particle size, rheology, and tribology characteristics of the yoghurt samples. With the increasing demand for low fat and functional food, there is a need to understand the impact of adding functional ingredients in low fat yoghurt to satisfy consumers' requirements. This study investigates the effects of these functional ingredients at different dosages on physical, rheology, tribology, and sensory characteristics of skim (0.1% fat) stirred yoghurt. The results from this study may guide use of functional ingredients in yoghurt production. © 2017 Wiley Periodicals, Inc.

Formulation and advantages of furazolidone in liposomal drug delivery systems.

PubMed

Alam, Muhammad Irfan; Paget, Timothy; Elkordy, Amal Ali

2016-03-10

Furazolidone has proven to have antiprotozoal and antibacterial activity. A number of literature supported its use against Helicobacter pylori. This potential application opens new prospects of its use in clinical settings in triple therapy. In order to avoid side effects associated with this drug, liposomal mucoadhesive drug delivery that can work locally in stomach is considered as an appropriate approach. This study is a focus on formulations and in vitro characterization of liposomes containing furazolidone. Therefore, the effects of variable amounts of drug and cholesterol on encapsulation efficacy and in vitro drug release were evaluated for different liposomal formulations. Mucoadhesive behavior of chitosan coated liposomal at two different pHs was also evaluated and increase in pH from 1.3 to 4.5 increased mucoadhesion from 42% to 60% respectively. Increasing the amount of drug from 4mg to 5mg increased encapsulation activity however, increasing the drug any further decreased encapsulation activity. In contrast, by increasing the amount of cholesterol decrease in encapsulation activity was observed. The optimized formulation with 5mg of drug and 53mg of cholesterol in formulation gave 57% drug release at pH 1.3 but release was increased up to 71% by increasing pH to 4.5 for same amount of drug. However, by using 10.6mg of cholesterol and 5mg of drug the overall release was increased at both pH conditions, at pH 1.3 release was 69% as compared to 77% at pH 4.5. This trend of drug release profile and mucoadhesion that favors pH 4.5 is documented as useful in targeting H. pylori as normal pH of stomach is expected to be higher by the influence of this microbe. Hence, the results of this research can be taken further into a future in vivo study. Copyright © 2016 Elsevier B.V. All rights reserved.

Modified sugar beet pectin induces apoptosis of colon cancer cells via interaction with the neutral sugar side-chains

USDA-ARS?s Scientific Manuscript database

Pectins extracted from a variety of sources and modified with heat and/or pH have previously been shown to exhibit activity towards several cancer cell lines. However, the structural basis for the anti-cancer activity of modified pectin requires clarification. Sugar beet and citrus pectin extracts h...

PLGA/polymeric liposome for targeted drug and gene co-delivery.

PubMed

Wang, Hanjie; Zhao, Peiqi; Su, Wenya; Wang, Sheng; Liao, Zhenyu; Niu, Ruifang; Chang, Jin

2010-11-01

Chemotherapy is one of the most effective approaches to treat cancers in the clinic, but the problems, such as multidrug resistance (MDR), low bioavailability and toxicity, severely constrain the further application of chemotherapy. Our group recently reported that cationic PLGA/folate coated PEGlated polymeric liposome core-shell nanoparticles (PLGA/FPL NPs). It was self-assembled from a hydrophobic PLGA core and a hydrophilic folate coated PEGlated lipid shell for targeting co-delivery of drug and gene. Hydrophobic drugs can be incorporated into the core and the cationic shell of the drug-loaded nanoparticles can be used to bind DNA. The drug-loaded PLGA/FPL NPs/DNA complexes offer advantages to overcome these problems mentioned above, such as co-delivery of drugs and DNA to improving the chemosensitivity of cancer cells at a gene level, and targeting delivery of drug to the cancer tissue that enhance the bioavailability and reduce the toxicity. The experiment showed that nanoparticles have core-shell structure with nanosize, sustained drug release profile and good DNA-binding ability. Importantly, the core-shell nanoparticles achieve the possibility of co-delivering drugs and genes to the same cells with high gene transfection and drug delivery efficiency. Our data suggest that the PLGA/FPL NPs may be a useful drug and gene co-delivery system. Copyright © 2010 Elsevier Ltd. All rights reserved.

Boron Supply Enhances Aluminum Tolerance in Root Border Cells of Pea (Pisum sativum) by Interacting with Cell Wall Pectins

PubMed Central

Fang, Jing; Tao, Lin; Shen, Ren Fang; Li, Ya Lin; Xiao, Hong Dong; Feng, Ying Ming; Wen, Hai Xiang; Guan, Jia Hua; Wu, Li Shu; He, Yong Ming; Goldbach, Heiner E.; Yu, Min

2017-01-01

Aluminum (Al) toxicity is the primary factor limiting crop growth in acidic soils. Boron (B) alleviates Al toxicity in plants, which is mainly considered to be due to the formation of Rhamnogalacturonan II-B (RGII-B) complexes, which helps to stabilize the cytoskeleton. It is unclear yet whether this is due to the increasing of net negative charges and/or further mechanisms. Kinetics of Al accumulation and adsorption were investigated using entire cells, cell wall and pectin of root border cells (RBCs) of pea (Pisum sativum), to reveal the mechanism of B in interacting with alkali-soluble and chelator-soluble pectin for an increased Al tolerance in RBCs. The results show that B could rescue RBCs from Al-induced cell death by accumulating more Al in the cell wall, predominately in alkali-soluble pectin. Boron also promotes Al3+ adsorption and inhibits Al3+ desorption from alkali-soluble pectin. Thus, more Al3+ is immobilized within the alkali-soluble pectin fraction and less in the chelator-soluble pectin, rendering Al3+ less mobile. Boron induces an increase of RG-II (KDO,2-keto-3-deoxyoctonic acid) content for forming more borate-RGII complexes, and the decrease of pectin methyl-esterification, thus creates more negative charges to immobilize Al3+ in cell wall pectin. The study provides evidence that abundant B supply enhances the immobilization of Al in alkali-soluble pectin, thus most likely reducing the entry of Al3+ into the symplast from the surroundings. PMID:28533794

Physicochemical and in vitro antioxidant properties of pectin extracted from hot pepper (Capsicum annuum L. var. acuminatum (Fingerh.)) residues with hydrochloric and sulfuric acids.

PubMed

Xu, Honggao; Tai, Kedong; Wei, Tong; Yuan, Fang; Gao, Yanxiang

2017-11-01

Transformation of hot pepper residues to value-added products with concomitant benefits on environmental pollution would be of great value to capsicum oleoresin manufacturers. Pectin, a soluble dietary fiber with multiple functions, from hot pepper residues was investigated in this study. The extraction of hot pepper pectin using hydrochloric acid was first optimized using response surface methodology (RSM). The most efficient parameters for maximum hot pepper pectin yield (14.63%, dry basis) were a pH of 1.0, a temperature of 90 °C, an extraction time of 2 h and a liquid-to-solid ratio of 20 L g -1 . The pectin was mainly composed of uronic acids, and the major neutral sugars were galactose and glucose. The structure of hot pepper pectin was characterized by homogalacturonan and rhamnogalacturonan I elements. The physicochemical properties of hot pepper pectin extracted by sulfuric acid and hydrochloric acid were further investigated. The content of protein and degree of esterification in hot pepper pectin extracted with sulfuric acid solution (SP) were higher (P < 0.05) than those in that extracted with hydrochloric acid solution (HP), while the mean molecular weight of SP was lower than that of HP. Compared with HP, SP exhibited higher viscosity and better emulsifying property. Based on the yield and physicochemical properties of hot pepper pectin, hot pepper residues would be a new source to obtain pectin, and SP would be more preferred than HP. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Pectin methyl esterases and pectins in normal and hyperhydric shoots of carnation cultured in vitro.

PubMed

Saher, Shady; Piqueras, Abel; Hellin, Eladio; Olmos, Enrique

2005-02-01

Control and hyperhydric micropropagated plantlets from three carnation cultivars have been used to study their pectin composition and the activity of pectin methyl esterases (PMEs; EC 3.1.1.11). Pectins are a highly heterogeneous group of polymers that contribute to cell adhesion, cell wall architecture, and cell wall mechanical strength. Pectins control cell wall porosity and cell wall ionic status and are implicated in intercellular space development. The degree of esterification of pectins is controlled by the activity of cell wall PMEs; their different actions can affect the properties of the cell wall, which have been considered important with respect to controlling the development of hyperhydricity. The total pectins of hyperhydric leaves of the three varieties were significantly reduced in comparison with controls. The pectate fraction was significantly increased in hyperhydric leaves of all varieties while soluble pectins and protopectins were significantly lower. The PME activity of hyperhydric leaves was higher (4-10 times) compared to controls of the three varieties. Isoelectric focusing of PME isozymes revealed the presence of three isoforms; neutral PME activity was the major isozyme in control and hyperhydric leaves of the three varieties, whilst a decrease in the activity of the acidic isoforms was observed in hyperhydric leaves. The different PME activities could regulate some of the structural changes related to hyperhydricity in micropropagated carnation plants.

Chromatographic study of highly methoxylated lime pectins deesterified by different pectin methyl-esterases.

PubMed

Ralet, M C; Bonnin, E; Thibault, J F

2001-03-25

The inter-molecular distribution of free carboxyl groups of two highly methoxylated pectins enzymatically deesterified by plant and fungus pectin methyl-esterases were investigated by size-exclusion (SEC) and ion-exchange chromatography (IEC). "Homogeneous" populations with respect to molar mass or charge density were thereby obtained and their chemical composition and physico-chemical properties (transport parameter for monovalent cations and calcium, calcium activity coefficient) were studied. Chemical analysis showed that the composition varies from one SEC fraction to another, the highest molar mass fraction being richer in rhamnose and galactose and exhibiting a slightly higher degree of methylation. Separation of pectins by IEC revealed a quite homogeneous charge density distribution for F58 contrary to P60 which exhibited a large distribution of methoxyl groups. The free carboxyl groups distributions and calcium binding behaviours of SEC and IEC fractions were shown to differ widely for highly methoxylated pectins deesterified by plant and fungus pectin methyl-esterases.

Structural Biology of Pectin Degradation by Enterobacteriaceae

PubMed Central

Abbott, D. Wade; Boraston, Alisdair B.

2008-01-01

Pectin is a structural polysaccharide that is integral for the stability of plant cell walls. During soft rot infection, secreted virulence factors from pectinolytic bacteria such as Erwinia spp. degrade pectin, resulting in characteristic plant cell necrosis and tissue maceration. Catabolism of pectin and its breakdown products by pectinolytic bacteria occurs within distinct cellular environments. This process initiates outside the cell, continues within the periplasmic space, and culminates in the cytoplasm. Although pectin utilization is well understood at the genetic and biochemical levels, an inclusive structural description of pectinases and pectin binding proteins by both extracellular and periplasmic enzymes has been lacking, especially following the recent characterization of several periplasmic components and protein-oligogalacturonide complexes. Here we provide a comprehensive analysis of the protein folds and mechanisms of pectate lyases, polygalacturonases, and carbohydrate esterases and the binding specificities of two periplasmic pectic binding proteins from Enterobacteriaceae. This review provides a structural understanding of the molecular determinants of pectin utilization and the mechanisms driving catabolite selectivity and flow through the pathway. PMID:18535148

Characterization of pectins extracted from pomegranate peel and their gelling properties.

PubMed

Abid, Mouna; Cheikhrouhou, S; Renard, Catherine M G C; Bureau, Sylvie; Cuvelier, Gérard; Attia, Hamadi; Ayadi, M A

2017-01-15

The composition of pomegranate peel, the main by-product during pomegranate processing, and some of the characteristics of the water-soluble pectins were investigated. Four tunisian pomegranate peels were subjected to hot aqueous extractions (86°C, 80min, 20mM nitric acid). Pomegranate peels yielded between 6.8% and 10.1% pectins. The extracted pectins were low methylated and were characterized by the predominance of homogalacturonan regions. Principal component analysis applied on FT-IR spectral data in the region between 4000 and 650cm(-1) differentiated the samples according to their degree of methylation. At pH 3, in the presence of 0.7% pectin, all solutions showed a rapid gel formation with G'>G″. With decreasing temperature from 90°C to 10°C, G' increased to reach a plateau at 10°C. The variation in the pectin gel formation between varieties was attributed to difference in pectin characteristics particularly the hydrodynamic volume and the neutral sugar content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Novel bioprinting method using a pectin based bioink.

PubMed

Banks, Amanda; Guo, Xiaoru; Chen, Junhong; Kumpaty, Subha; Zhang, Wujie

2017-08-09

One major challenge of bioprinting is to develop a viable bioink to act as an extracellular matrix. This study investigated a novel method for bioprinting using a pectin based bioink. Besides pectin, Pluronic® F-127 was incorporated into the bioink to obtain the desired shape during the initial bioprinting process at 37∘C. Once an object was printed it was treated with Ca2+ (pectin cross-linker) to create the final tissue/organ structure. The results indicated that pectin/Pluronic® F-127 is a potential bioink. Moreover, this methodology provides a novel and fast approach for bioprinting.

Phylogenetic analysis of pectin-related gene families in Physcomitrella patens and nine other plant species yields evolutionary insights into cell walls

PubMed Central

2014-01-01

Background Pectins are acidic sugar-containing polysaccharides that are universally conserved components of the primary cell walls of plants and modulate both tip and diffuse cell growth. However, many of their specific functions and the evolution of the genes responsible for producing and modifying them are incompletely understood. The moss Physcomitrella patens is emerging as a powerful model system for the study of plant cell walls. To identify deeply conserved pectin-related genes in Physcomitrella, we generated phylogenetic trees for 16 pectin-related gene families using sequences from ten plant genomes and analyzed the evolutionary relationships within these families. Results Contrary to our initial hypothesis that a single ancestral gene was present for each pectin-related gene family in the common ancestor of land plants, five of the 16 gene families, including homogalacturonan galacturonosyltransferases, polygalacturonases, pectin methylesterases, homogalacturonan methyltransferases, and pectate lyase-like proteins, show evidence of multiple members in the early land plant that gave rise to the mosses and vascular plants. Seven of the gene families, the UDP-rhamnose synthases, UDP-glucuronic acid epimerases, homogalacturonan galacturonosyltransferase-like proteins, β-1,4-galactan β-1,4-galactosyltransferases, rhamnogalacturonan II xylosyltransferases, and pectin acetylesterases appear to have had a single member in the common ancestor of land plants. We detected no Physcomitrella members in the xylogalacturonan xylosyltransferase, rhamnogalacturonan I arabinosyltransferase, pectin methylesterase inhibitor, or polygalacturonase inhibitor protein families. Conclusions Several gene families related to the production and modification of pectins in plants appear to have multiple members that are conserved as far back as the common ancestor of mosses and vascular plants. The presence of multiple members of these families even before the divergence of other important cell wall-related genes, such as cellulose synthases, suggests a more complex role than previously suspected for pectins in the evolution of land plants. The presence of relatively small pectin-related gene families in Physcomitrella as compared to Arabidopsis makes it an attractive target for analysis of the functions of pectins in cell walls. In contrast, the absence of genes in Physcomitrella for some families suggests that certain pectin modifications, such as homogalacturonan xylosylation, arose later during land plant evolution. PMID:24666997

Pectin Methylesterase and Pectin Remodelling Differ in the Fibre Walls of Two Gossypium Species with Very Different Fibre Properties

PubMed Central

Liu, Qinxiang; Talbot, Mark; Llewellyn, Danny J.

2013-01-01

Pectin, a major component of the primary cell walls of dicot plants, is synthesized in Golgi, secreted into the wall as methylesters and subsequently de-esterified by pectin methylesterase (PME). Pectin remodelling by PMEs is known to be important in regulating cell expansion in plants, but has been poorly studied in cotton. In this study, genome-wide analysis showed that PMEs are a large multi-gene family (81 genes) in diploid cotton (Gossypium raimondii), an expansion over the 66 in Arabidopsis and suggests the evolution of new functions in cotton. Relatively few PME genes are expressed highly in fibres based on EST abundance and the five most abundant in fibres were cloned and sequenced from two cotton species. Their significant sequence differences and their stage-specific expression in fibres within a species suggest sub-specialisation during fibre development. We determined the transcript abundance of the five fibre PMEs, total PME enzyme activity, pectin content and extent of de-methylesterification of the pectin in fibre walls of the two cotton species over the first 25–30 days of fibre growth. There was a higher transcript abundance of fibre-PMEs and a higher total PME enzyme activity in G. barbadense (Gb) than in G. hirsutum (Gh) fibres, particularly during late fibre elongation. Total pectin was high, but de-esterified pectin was low during fibre elongation (5–12 dpa) in both Gh and Gb. De-esterified pectin levels rose thereafter when total PME activity increased and this occurred earlier in Gb fibres resulting in a lower degree of esterification in Gb fibres between 17 and 22 dpa. Gb fibres are finer and longer than those of Gh, so differences in pectin remodelling during the transition to wall thickening may be an important factor in influencing final fibre diameter and length, two key quality attributes of cotton fibres. PMID:23755181

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization.

PubMed

Gopi, D; Kanimozhi, K; Bhuvaneshwari, N; Indira, J; Kavitha, L

2014-01-24

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy ((1)H NMR) and carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization

NASA Astrophysics Data System (ADS)

Gopi, D.; Kanimozhi, K.; Bhuvaneshwari, N.; Indira, J.; Kavitha, L.

2014-01-01

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy (1H NMR) and carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications.

Methyl esterification of pectin plays a role during plant-pathogen interactions and affects plant resistance to diseases.

PubMed

Lionetti, Vincenzo; Cervone, Felice; Bellincampi, Daniela

2012-11-01

The cell wall is a complex structure mainly composed by a cellulose-hemicellulose network embedded in a cohesive pectin matrix. Pectin is synthesized in a highly methyl esterified form and is de-esterified in muro by pectin methyl esterases (PMEs). The degree and pattern of methyl esterification affect the cell wall structure and properties with consequences on both the physiological processes of the plants and their resistance to pathogens. PME activity displays a crucial role in the outcome of the plant-pathogen interactions by making pectin more susceptible to the action of the enzymes produced by the pathogens. This review focuses on the impact of pectin methyl esterification in plant-pathogen interactions and on the dynamic role of its alteration during pathogenesis. Copyright © 2012 Elsevier GmbH. All rights reserved.

Propidium iodide competes with Ca(2+) to label pectin in pollen tubes and Arabidopsis root hairs.

PubMed

Rounds, Caleb M; Lubeck, Eric; Hepler, Peter K; Winship, Lawrence J

2011-09-01

We have used propidium iodide (PI) to investigate the dynamic properties of the primary cell wall at the apex of Arabidopsis (Arabidopsis thaliana) root hairs and pollen tubes and in lily (Lilium formosanum) pollen tubes. Our results show that in root hairs, as in pollen tubes, oscillatory peaks in PI fluorescence precede growth rate oscillations. Pectin forms the primary component of the cell wall at the tip of both root hairs and pollen tubes. Given the electronic structure of PI, we investigated whether PI binds to pectins in a manner analogous to Ca(2+) binding. We first show that Ca(2+) is able to abrogate PI growth inhibition in a dose-dependent manner. PI fluorescence itself also relies directly on the amount of Ca(2+) in the growth solution. Exogenous pectin methyl esterase treatment of pollen tubes, which demethoxylates pectins, freeing more Ca(2+)-binding sites, leads to a dramatic increase in PI fluorescence. Treatment with pectinase leads to a corresponding decrease in fluorescence. These results are consistent with the hypothesis that PI binds to demethoxylated pectins. Unlike other pectin stains, PI at low yet useful concentration is vital and specifically does not alter the tip-focused Ca(2+) gradient or growth oscillations. These data suggest that pectin secretion at the apex of tip-growing plant cells plays a critical role in regulating growth, and PI represents an excellent tool for examining the role of pectin and of Ca(2+) in tip growth.

Effects of microwave power and irradiation time on pectin extraction from watermelon rinds (Citrullus lanatus) with acetic acid using microwave assisted extraction method

NASA Astrophysics Data System (ADS)

Sari, A. M.; Ishartani, D.; Dewanty, P. S.

2018-01-01

The aims of this research are to study the effect of microwave power (119.7 W, 199.5 W and 279.3 W) and irradiation time (6, 9 and 12 min) on pectin extraction by using Microwave Assisted Extraction (MAE) with acetic acid and to do a preliminary characterization of pectin from watermelon rinds. A randomized factorial design with two factors was used to determine the effect of microwave power and processing time on the yield, equivalent weight, degree of methoxylation (DM), galacturonic acid content (GA) and the degree of esterification (DE) of extracted pectin. The results showed that extracted pectin from watermelon rinds using MAE method have yield ranged from 3.925% to 5.766%, with equivalent weight ranged from 1249.702 to 2007.756. Extracted pectin have a DM value ranged from 3.89% to 10.81%. Galacturonic acid content that meets with IPPA standard resulted from extraction condition of 279.3-watt microwave power for 9 min and 12 min. The degree of esterification (DE) value ranged from 56.86% to 85.76%, and this value exhibited a relatively high methoxyl pectin (>50%). The best pectin properties was obtained at a microwave power of 279.3 watts for 12 min.

Mechanical properties, structure, bioadhesion, and biocompatibility of pectin hydrogels.

PubMed

Markov, Pavel A; Krachkovsky, Nikita S; Durnev, Eugene A; Martinson, Ekaterina A; Litvinets, Sergey G; Popov, Sergey V

2017-09-01

The surface structure, biocompatibility, textural, and adhesive properties of calcium hydrogels derived from 1, 2, and 4% solutions of apple pectin were examined in this study. An increase in the pectin concentration in hydrogels was shown to improve their stability toward elastic and plastic deformation. The elasticity of pectin hydrogels, measured as Young's modulus, ranged from 6 to 100 kPa. The mechanical properties of the pectin hydrogels were shown to correspond to those of soft tissues. The characterization of surface roughness in terms of the roughness profile (Ra) and the root-mean-square deviation of the roughness profile (Rq) indicated an increased roughness profile for hydrogels depending on their pectin concentration. The adhesion of AU2% and AU4% hydrogels to the serosa abdominal wall, liver, and colon was higher than that of the AU1% hydrogel. The adhesion of macrophages and the non-specific adsorption of blood plasma proteins were found to increase as the pectin concentration in the hydrogels increased. The rate of degradation of all hydrogels was higher in phosphate buffered saline (PBS) than that in DMEM and a fibroblast cell monolayer. The pectin hydrogel was also found to have a low cytotoxicity. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2572-2581, 2017. © 2017 Wiley Periodicals, Inc.

Pectin: cell biology and prospects for functional analysis.

PubMed

Willats, W G; McCartney, L; Mackie, W; Knox, J P

2001-09-01

Pectin is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides. Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan-I and rhamnogalacturonan-II) are thought to occur in all primary cell walls. This review surveys what is known about the structure and function of these pectin domains. The high degree of structural complexity and heterogeneity of the pectic matrix is produced both during biosynthesis in the endomembrane system and as a result of the action of an array of wall-based pectin-modifying enzymes. Recent developments in analytical techniques and in the generation of anti-pectin probes have begun to place the structural complexity of pectin in cell biological and developmental contexts. The in muro de-methyl-esterification of homogalacturonan by pectin methyl esterases is emerging as a key process for the local modulation of matrix properties. Rhamnogalacturonan-I comprises a highly diverse population of spatially and developmentally regulated polymers, whereas rhamnogalacturonan-II appears to be a highly conserved and stable pectic domain. Current knowledge of biosynthetic enzymes, plant and microbial pectinases and the interactions of pectin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development.

Stiffness of Ca(2+)-pectin gels: combined effects of degree and pattern of methylesterification for various Ca(2+) concentrations.

PubMed

Ngouémazong, Doungla E; Jolie, Ruben P; Cardinaels, Ruth; Fraeye, Ilse; Van Loey, Ann; Moldenaers, Paula; Hendrickx, Marc

2012-02-01

The influence of the degree and pattern of methylesterification (DM and PM, respectively) on the stiffness of Ca(2+)-pectin gels is extensively examined, at various Ca(2+) concentrations. Accordingly, a highly methyl-esterified pectin was selectively de-esterified using NaOH, plant or fungal pectin methylesterase in order to produce series of pectins with varied pattern and broad ranges of methylesterification. The PM was quantified as absolute degree of blockiness (DB(abs)). Ca(2+)-pectin gels were prepared at various Ca(2+) concentrations. Gel stiffness (G' at 1rad/s) was determined and mapped out as a function of DM, DB(abs) and Ca(2+) concentration. At low Ca(2+) concentrations, G' depends on polymer's DM and DB(abs). At high Ca(2+) concentrations, a master curve is obtained over a wide range of DM, irrespective of DB(abs). Depending on methylesterification pattern, increase of G' is related not only to an increase in the number of junction zones per pectin chain, but also to an increase in the size of junction zones and the number of dimerised chains occurring in the gels. These results provide a detailed insight into the occurrence of junction zones in Ca(2+)-pectin gels. Copyright © 2011 Elsevier Ltd. All rights reserved.

Preparation of pectin/silver nanoparticles composite films with UV-light barrier and properties.

PubMed

Shankar, Shiv; Tanomrod, Nattareya; Rawdkuen, Saroat; Rhim, Jong-Whan

2016-11-01

Silver nanoparticles (AgNPs) was synthesized by a green method using an aqueous extract of Caesalpinia mimosoides Lamk (CMLE) as reducing and stabilizing agents, and they were used for the preparation of pectin-based antimicrobial composite films. The AgNPs were spherical in shape with the size in the range of 20-80nm and showed the absorption peak around 500nm. The pectin/AgNPs composite film exhibited characteristic absorption peak of AgNPs at 480nm. The surface color and light transmittance of the pectin films were greatly influenced by the addition of AgNPs. The lightness of the films decreased, however, redness and yellowness of the films increased after incorporation of AgNPs. UV-light barrier property of the pectin film increased significantly with a little decrease in the transparency. Though there were no structural changes in the pectin film by the incorporation of CMLE and AgNPs as indicated by the FTIR results, the film properties such as thermal stability, mechanical strength, and water vapor barrier properties of the pectin films increased. The pectin/AgNPs nanocomposite films exhibited strong antibacterial activity against food-borne pathogenic bacteria, Escherichia coli and Listeria monocytogenes. Copyright © 2016 Elsevier B.V. All rights reserved.

Pectin/zein beads for potential colon-specific drug delivery: synthesis and in vitro evaluation.

PubMed

Liu, LinShu; Fishman, Marshall L; Hicks, Kevin B; Kende, Meir; Ruthel, Gordon

2006-01-01

Novel complex hydrogel beads were prepared from two edible polymers: pectin, a carbohydrate from citrus fruits, and zein, a protein from corn. The pectin/zein complex hydrogels did not swell in physiological environments, but hydrolyzed in the presence of pectinases. An in vitro study showed the capacity of the hydrogels to endure protease attack and residence time variation. The physical and biological properties of the new hydrogels were attributed to molecular entanglement of the two polymers. The pectin networks were stabilized by the bound zein molecules. In turn, the pectin networks shielded the bound zein from protease digestion.

Influence of protein-pectin electrostatic interaction on the foam stability mechanism.

PubMed

Sadahira, Mitie S; Lopes, Fernanda C Rezende; Rodrigues, Maria I; Netto, Flavia M

2014-03-15

This study aimed at evaluating the effect of three independent variables: biopolymer concentration (egg white proteins and pectin) (2.0-4.0%, w/w); protein:pectin ratio (15:1-55:1); and temperature (70-80 °C), at pH 3.0, using a central composite design on the foaming properties (overrun, drainage and bubble growth rate). Foams produced with protein:pectin ratio 15:1 showed the lowest bubble growth rate and the greatest drainage, whereas protein:pectin ratio 55:1 presented the lowest drainage. Complexes obtained with protein:pectin ratio 15:1 were close to electroneutrality and showed larger size (95.91 ± 8.19 μm) than those obtained with protein:pectin ratio 55:1 (45.92 ± 3.47 μm) not electrically neutral. Larger particles seemed to build an interfacial viscoelastic network at the air-water interface with reduced gas permeability, leading to greater stability concerning the disproportionation. Soluble complexes of smaller sizes increased viscosity leading to a low drainage of liquid and inhibiting the bubbles coalescence. Copyright © 2013 Elsevier Ltd. All rights reserved.

Potato tuber pectin structure is influenced by pectin methyl esterase activity and impacts on cooked potato texture.

PubMed

Ross, Heather A; Wright, Kathryn M; McDougall, Gordon J; Roberts, Alison G; Chapman, Sean N; Morris, Wayne L; Hancock, Robert D; Stewart, Derek; Tucker, Gregory A; James, Euan K; Taylor, Mark A

2011-01-01

Although cooked potato tuber texture is an important trait that influences consumer preference, a detailed understanding of tuber textural properties at the molecular level is lacking. Previous work has identified tuber pectin methyl esterase activity (PME) as a potential factor impacting on textural properties. In this study, tuber PME isoform and gene expression profiles have been determined in potato germplasm with differing textural properties as assessed using an amended wedge fracture method and a sloughing assay, revealing major differences between the potato types. Differences in pectin structure between potato types with different textural properties were revealed using monoclonal antibodies specific for different pectic epitopes. Chemical analysis of tuber pectin clearly demonstrated that, in tubers containing a higher level of total PME activity, there was a reduced degree of methylation of cell wall pectin and consistently higher peak force and work done values during the fracture of cooked tuber samples, demonstrating the link between PME activity, the degree of methylation of cell wall pectin, and cooked tuber textural properties.

Potato tuber pectin structure is influenced by pectin methyl esterase activity and impacts on cooked potato texture

PubMed Central

Ross, Heather A.; Wright, Kathryn M.; McDougall, Gordon J.; Roberts, Alison G.; Chapman, Sean N.; Morris, Wayne L.; Hancock, Robert D.; Stewart, Derek; Tucker, Gregory A.; James, Euan K.; Taylor, Mark A.

2011-01-01

Although cooked potato tuber texture is an important trait that influences consumer preference, a detailed understanding of tuber textural properties at the molecular level is lacking. Previous work has identified tuber pectin methyl esterase activity (PME) as a potential factor impacting on textural properties. In this study, tuber PME isoform and gene expression profiles have been determined in potato germplasm with differing textural properties as assessed using an amended wedge fracture method and a sloughing assay, revealing major differences between the potato types. Differences in pectin structure between potato types with different textural properties were revealed using monoclonal antibodies specific for different pectic epitopes. Chemical analysis of tuber pectin clearly demonstrated that, in tubers containing a higher level of total PME activity, there was a reduced degree of methylation of cell wall pectin and consistently higher peak force and work done values during the fracture of cooked tuber samples, demonstrating the link between PME activity, the degree of methylation of cell wall pectin, and cooked tuber textural properties. PMID:20855456

Deficiency of adenosine kinase activity affects the degree of pectin methyl-esterification in cell walls of Arabidopsis thaliana.

PubMed

Pereira, L A R; Schoor, S; Goubet, F; Dupree, P; Moffatt, B A

2006-11-01

Pectin methyl-esterification is catalysed by S-adenosyl-L: -methionine (SAM)-dependent methyltransferases. As deficiency in adenosine kinase (ADK; EC 2.7.1.20) activity impairs SAM recycling and utilization, we investigated the relationship between ADK-deficiency and the degree of pectin methyl-esterification in cell walls of Arabidopsis thaliana. The distribution patterns of epitopes associated with methyl-esterified homogalacturonan in leaves and hypocotyls of wild-type (WT) and ADK-deficient plants were examined using immunolocalization and biochemical techniques. JIM5 and LM7 epitopes, characteristic of low esterified pectins, were more irregularly distributed along the cell wall in ADK-deficient plants than in WT cell walls. In addition, epitopes recognized by JIM7, characteristic of pectins with a higher degree of methyl-esterification, were less abundant in ADK-deficient leaves and hypocotyls. Since de-esterified pectins have enhanced adhesion properties, we propose that the higher abundance and the altered distribution of low methyl-esterified pectin in ADK-deficient cell walls lead to the leaf shape abnormalities observed in these plants.

Pectin-based nanocomposite aerogels for potential insulated food packaging application.

PubMed

Nešić, Aleksandra; Gordić, Milan; Davidović, Sladjana; Radovanović, Željko; Nedeljković, Jovan; Smirnova, Irina; Gurikov, Pavel

2018-09-01

Environmental-friendly pectin-TiO 2 nanocomposite aerogels were prepared via sol-gel process and subsequent drying under supercritical conditions. The first step includes dissolution of pectin in water, addition of proper amount of TiO 2 colloid and crosslinking reaction induced in the presence of tert-butanol and zinc ions. Then, the gels are subjected to the solvent exchange and supercritical CO 2 drying. The influence of TiO 2 nanoparticles on the textural, mechanical, thermal and antibacterial properties of aerogels was investigated. Results indicate that in the presence of TiO 2 nanoparticles (NPs) mechanical, thermal and antimicrobial properties of pectin-based aerogels are improved in comparison to the control pectin aerogels. It should be emphasized that the thermal conductivity of pectin-based aerogels (0.022-0.025 W m -1  K -1 ) is lower than the thermal conductivity of air. Generally, the results propose that the pectin-TiO 2 nanocomposite aerogels, as bio-based material, might have potential application for the storage of temperature-sensitive food. Copyright © 2018 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mort, Andrew

At the beginning of this project we hypothesized that pectin, which is a major polysaccharide in primary plant cell walls, is composed of various distinct structural regions covalently linked together into a high molecular weight complex polymer. We also hypothesized that a considerable portion of xyloglucan, the major hemicellulose in most primary cell walls, is linked to the pectin. Our goal was to determine if these interconnections exist and to characterize the exact nature of the interactions. It seems imperative that we have a complete knowledge of the structure of pectin to be able to propose realistic models of cellmore » walls. There is a lot of interest in the biosynthesis of pectin. I do not think it will be possible to completely understand the biosynthesis of pectin without knowing the structure of pectin and thus the sequence of reactions needed to put each sugar or ester in its correct position in the polymer. We made considerable progress in determining the detailed structure of pectin and within a year or so will be able to put forward a comprehensive model of it.« less

In vitro pyrogen test for toxic or immunomodulatory drugs.

PubMed

Daneshian, Mardas; Guenther, Armin; Wendel, Albrecht; Hartung, Thomas; von Aulock, Sonja

2006-06-30

Pyrogenic contaminations of some classes of injectable drugs, e.g. toxic or immunomodulatory as well as false-positive drugs, represent a major risk which cannot yet be excluded due to the limitations of current tests. Here we describe a modification of the In vitro Pyrogen Test termed AWIPT (Adsorb, Wash, In vitro Pyrogen Test), which addresses this problem by introducing a pre-incubation step in which pyrogenic contaminations in the test sample are adsorbed to albumin-coated beads. After rinsing, the beads are incubated with human whole blood and the release of the endogenous pyrogen interleukin-1beta is measured as a marker of pyrogenic activity. Intentional contaminations with lipopolysaccharide were retrieved from the chemotherapeutic agents paclitaxel, cisplatin and liposomal daunorubicin, the antibiotic gentamicin, the antifungal agent liposomal amphotericin B, and the corticosteroid prednisolone at lower dilutions than in the standard in vitro pyrogen test. This represents a promising new approach for the detection of pyrogenic contamination in drugs or in drugs containing interfering additives and should lead to improved safety levels.

Expression of a codon-optimized Aspergillus niger pectin methylesterase gene in the methylotrophic yeast Candida boidinii.

PubMed

Kawaguchi, Kosuke; Yurimoto, Hiroya; Sakai, Yasuyoshi

2014-01-01

A codon-optimized Aspergillus niger pectin methylesterase (PME) gene was expressed in the methylotrophic yeast Canidia boidinii. The PME-producing strains showed better growth on pectin than the wild-type strains, suggesting that the PME-producing strains could efficiently utilize methyl ester moieties of pectin. On the other hand, overproduction of PME negatively affected the proliferation of C. boidinii on leaves of Arabidopsis thaliana.

Characterisation of pectins extracted from banana peels (Musa AAA) under different conditions using an experimental design.

PubMed

Happi Emaga, Thomas; Ronkart, Sébastien N; Robert, Christelle; Wathelet, Bernard; Paquot, Michel

2008-05-15

An experimental design was used to study the influence of pH (1.5 and 2.0), temperature (80 and 90°C) and time (1 and 4h) on extraction of pectin from banana peels (Musa AAA). Yield of extracted pectins, their composition (neutral sugars, galacturonic acid, and degree of esterification) and some macromolecular characteristics (average molecular weight, intrinsic viscosity) were determined. It was found that extraction pH was the most important parameter influencing yield and pectin chemical composition. Lower pH values negatively affected the galacturonic acid content of pectin, but increased the pectin yield. The values of degree of methylation decreased significantly with increasing temperature and time of extraction. The average molecular weight ranged widely from 87 to 248kDa and was mainly influenced by pH and extraction time. Copyright © 2007 Elsevier Ltd. All rights reserved.

Propidium Iodide Competes with Ca2+ to Label Pectin in Pollen Tubes and Arabidopsis Root Hairs1[W][OA

PubMed Central

Rounds, Caleb M.; Lubeck, Eric; Hepler, Peter K.; Winship, Lawrence J.

2011-01-01

We have used propidium iodide (PI) to investigate the dynamic properties of the primary cell wall at the apex of Arabidopsis (Arabidopsis thaliana) root hairs and pollen tubes and in lily (Lilium formosanum) pollen tubes. Our results show that in root hairs, as in pollen tubes, oscillatory peaks in PI fluorescence precede growth rate oscillations. Pectin forms the primary component of the cell wall at the tip of both root hairs and pollen tubes. Given the electronic structure of PI, we investigated whether PI binds to pectins in a manner analogous to Ca2+ binding. We first show that Ca2+ is able to abrogate PI growth inhibition in a dose-dependent manner. PI fluorescence itself also relies directly on the amount of Ca2+ in the growth solution. Exogenous pectin methyl esterase treatment of pollen tubes, which demethoxylates pectins, freeing more Ca2+-binding sites, leads to a dramatic increase in PI fluorescence. Treatment with pectinase leads to a corresponding decrease in fluorescence. These results are consistent with the hypothesis that PI binds to demethoxylated pectins. Unlike other pectin stains, PI at low yet useful concentration is vital and specifically does not alter the tip-focused Ca2+ gradient or growth oscillations. These data suggest that pectin secretion at the apex of tip-growing plant cells plays a critical role in regulating growth, and PI represents an excellent tool for examining the role of pectin and of Ca2+ in tip growth. PMID:21768649

A novel and organic solvent-free preparation of solid lipid nanoparticles using natural biopolymers as emulsifier and stabilizer.

PubMed

Xue, Jingyi; Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Luo, Yangchao

2017-10-05

In this work, a new and novel organic solvent-free and synthetic surfactant-free method was reported to fabricate stable solid lipid nanoparticles (SLNs) from stearic acid, sodium caseinate (NaCas) and pectin, as well as water. Melted stearic acid was directly emulsified into an aqueous phase containing NaCas and pectin, followed by pH adjustment and thermal treatment to induce the formation of a compact and dense polymeric coating which stabilized SLNs. The preparation procedures and formulations were comprehensively optimized. The inter- and intra-molecular interactions among three ingredients were characterized by fluorescence and Fourier transform infrared spectroscopies. The stability of as-prepared SLNs was evaluated under simulated gastrointestinal conditions, and compared with traditional SLNs prepared with organic solvents. Our results revealed that the SLNs prepared from this organic solvent-free method had superior physicochemical properties over the traditional SLNs, including smaller size and better stability. Furthermore, redispersible SLNs powders were obtained by nano spray drying, but only the SLNs prepared by organic solvent-free method had sub-micron scale, uniform and spherical morphology. The organic solvent-free preparation method was proved to be a promising approach to prepare stable and uniform SLNs for potential oral delivery applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Organ and Tissue-Specific Localisation of Selected Cell Wall Epitopes in the Zygotic Embryo of Brachypodium distachyon.

PubMed

Betekhtin, Alexander; Milewska-Hendel, Anna; Lusinska, Joanna; Chajec, Lukasz; Kurczynska, Ewa; Hasterok, Robert

2018-03-03

The plant cell wall shows a great diversity regarding its chemical composition, which may vary significantly even during different developmental stages. In this study, we analysed the distribution of several cell wall epitopes in embryos of Brachypodium distachyon (Brachypodium). We also described the variations in the nucleus shape and the number of nucleoli that occurred in some embryo cells. The use of transmission electron microscopy, and histological and immunolocalisation techniques permitted the distribution of selected arabinogalactan proteins, extensins, pectins, and hemicelluloses on the embryo surface, internal cell compartments, and in the context of the cell wall ultrastructure to be demonstrated. We revealed that the majority of arabinogalactan proteins and extensins were distributed on the cell surface and that pectins were the main component of the seed coat and other parts, such as the mesocotyl cell walls and the radicula. Hemicelluloses were localised in the cell wall and outside of the radicula protodermis, respectively. The specific arrangement of those components may indicate their significance during embryo development and seed germination, thus suggesting the importance of their protective functions. Despite the differences in the cell wall composition, we found that some of the antibodies can be used as markers to identify specific cells and the parts of the developing Brachypodium embryo.

Design of ligand-targeted nanoparticles for enhanced cancer targeting

NASA Astrophysics Data System (ADS)

Stefanick, Jared F.

Ligand-targeted nanoparticles are increasingly used as drug delivery vehicles for cancer therapy, yet have not consistently produced successful clinical outcomes. Although these inconsistencies may arise from differences in disease models and target receptors, nanoparticle design parameters can significantly influence therapeutic efficacy. By employing a multifaceted synthetic strategy to prepare peptide-targeted nanoparticles with high purity, reproducibility, and precisely controlled stoichiometry of functionalities, this work evaluates the roles of polyethylene glycol (PEG) coating, ethylene glycol (EG) peptide-linker length, peptide hydrophilicity, peptide density, and nanoparticle size on tumor targeting in a systematic manner. These parameters were analyzed in multiple disease models by targeting human epidermal growth factor receptor 2 (HER2) in breast cancer and very late antigen-4 (VLA-4) in multiple myeloma to demonstrate the widespread applicability of this approach. By increasing the hydrophilicity of the targeting peptide sequence and simultaneously optimizing the EG peptide-linker length, the in vitro cellular uptake of targeted liposomes was significantly enhanced. Specifically, including a short oligolysine chain adjacent to the targeting peptide sequence effectively increased cellular uptake ~80-fold using an EG6 peptide-linker compared to ~10-fold using an EG45 linker. In vivo, targeted liposomes prepared in a traditional manner lacking the oligolysine chain demonstrated similar biodistribution and tumor uptake to non-targeted liposomes. However, by including the oligolysine chain, targeted liposomes using an EG45 linker significantly improved tumor uptake ~8-fold over non-targeted liposomes, while the use of an EG6 linker decreased tumor accumulation and uptake, owing to differences in cellular uptake kinetics, clearance mechanisms, and binding site barrier effects. To further improve tumor targeting and enhance the selectivity of targeted nanoparticles, a dual-receptor targeted approach was evaluated by targeting multiple cell surface receptors simultaneously. Liposomes functionalized with two distinct peptide antagonists to target VLA-4 and Leukocyte Peyer's Patch Adhesion Molecule-1 (LPAM-1) demonstrated synergistically enhanced cellular uptake by cells overexpressing both target receptors and negligible uptake by cells that do not simultaneously express both receptors, providing a strategy to improve selectivity over conventional single receptor-targeted designs. Taken together, this process of systematic optimization of well-defined nanoparticle drug delivery systems has the potential to improve cancer therapy for a broader patient population.

Structure of the PTEN-like region of auxilin, a detector of clathrin-coated vesicle budding

PubMed Central

Guan, Rong; Han, Dai; Harrison, Stephen C.; Kirchhausen, Tomas

2010-01-01

Auxilin, a J-domain containing protein, recruits the Hsc70 uncoating ATPase to newly budded clathrin-coated vesicles. The timing of auxilin arrival determines that uncoating will commence only after the clathrin lattice has fully assembled and after membrane fission is complete. Auxilin has a region resembling PTEN, a PI3P phosphatase. We have determined the crystal structure of this region of bovine auxilin 1; it indeed resembles PTEN closely. A change in the structure of the P-loop accounts for the lack of phosphatase activity. Inclusion of phosphatidylinositol phosphates substantially enhances liposome binding by wild-type auxilin, but not by various mutants bearing changes in loops of the C2 domain. Nearly all these mutations also prevent recruitment of auxilin to newly budded coated vesicles. We propose a specific geometry for auxilin association with a membrane bilayer and discuss implications of this model for the mechanism by which auxilin detects separation of a vesicle from its parent membrane. PMID:20826345

Preparation and characterization of collagen-hydroxyapatite/pectin composite.

PubMed

Wenpo, Feng; Gaofeng, Liang; Shuying, Feng; Yuanming, Qi; Keyong, Tang

2015-03-01

Pectin, a kind of plant polysaccharide, was introduced into collagen-hydroxyapatite composite system, and prepared collagen-hydroxyapatite/pectin (Col-HA/pectin) composite in situ. The structure of the composite was investigated by XRD, SEM, and FT-IR. The mechanical properties, water absorption, enzyme degradation, and cytotoxicity of the composite were investigated as well. The results show that the inorganic substance in the composite materials is hydroxyapatite in relatively low crystallinity. A new interface appeared by the interaction among hydroxyapatite and collagen-pectin, and formed smooth fine particles. The mechanical properties, water absorption, enzyme degradation, and cytotoxicity indicate a potential use in bone replacement for the new composite. Copyright © 2014 Elsevier B.V. All rights reserved.

Engineering of acidic O/W emulsions with pectin.

PubMed

Alba, K; Sagis, L M C; Kontogiorgos, V

2016-09-01

Pectins with distinct molecular design were isolated by aqueous extraction at pH 2.0 or 6.0 and were examined in terms of their formation and stabilisation capacity of model n-alkane-in-water emulsions at acidic pH (pH 2.0). The properties and stability of the resulting emulsions were examined by means of droplet size distribution analysis, Lifshitz-Slyozov-Wagner modelling, bulk rheology, interfacial composition analysis, large-amplitude oscillatory surface dilatational rheology, electrokinetic analysis and fluorescence microscopy. Both pectin preparations were able to emulsify alkanes in water but exhibited distinct ageing characteristics. Emulsions prepared using pectin isolated at pH 6.0 were remarkably stable with respect to droplet growth after thirty days of ageing, while those prepared with pectin isolated at pH 2.0 destabilised rapidly. Examination of chemical composition of interfacial layers indicated multi-layered adsorption of pectins at the oil-water interface. The higher long-term stability of emulsions prepared with pectin isolated at high pH is attributed to mechanically stronger interfaces, the highly branched nature and the low hydrodynamic volume of the chains that result in effective steric stabilisation whereas acetyl and methyl contents do not contribute to the long-term stability. The present work shows that it is possible by tailoring the fine structure of pectin to engineer emulsions that operate in acidic environments. Copyright © 2016 Elsevier B.V. All rights reserved.

Orange pectin mediated growth and stability of aqueous gold and silver nanocolloids

NASA Astrophysics Data System (ADS)

Nigoghossian, Karina; dos Santos, Molíria V.; Barud, Hernane S.; da Silva, Robson R.; Rocha, Lucas A.; Caiut, José M. A.; de Assunção, Rosana M. N.; Spanhel, Lubomir; Poulain, Marcel; Messaddeq, Younes; Ribeiro, Sidney J. L.

2015-06-01

The role of orange based pectin in the nucleation and growth of silver and gold nanoparticles is addressed. Pectin is a complex polysaccharide found in fruits such as oranges, lemons, passion fruits or apples. It displays smooth and hairy chain regions containing hydroxyl-, ester-, carboxylate- and eventually amine groups that can act as surface ligands interacting under various pH conditions more or less efficiently with growing nanometals. Here, a high methoxy pectin (>50% esterified) was used as a stabilizer/reducing agent in the preparation of gold, silver and silver-gold nanoparticles. Commercial pectin (CP) and pectin extracted from orange bagasse (OP) were used. Optionally, trisodium citrate or oxalic acid we used to reduce AgNO3 and HAuCl4 in aqueous environment. Characterization methods included UV-vis absorption spectroscopy, transmission electron microscopy, electron diffraction and energy-dispersive X-ray spectroscopy. The results show that under different pH conditions, pectin and reducing agents allow producing various nanostructures shapes (triangles, spheres, rods, octahedrons and decahedrons) often with high polydispersity and sizes ranging between 5 nm and 30 nm. In addition, depending on Ag/Au-ratio and pH, the surface plasmon bands can be continuously shifted between 410 nm and 600 nm. Finally, pectin seems to be a highly efficient stabilizer of the colloidal systems that show a remarkable stability and unchanged optical spectral response even after five years.

Acetylesterase-Mediated Deacetylation of Pectin Impairs Cell Elongation, Pollen Germination, and Plant Reproduction[C][W

PubMed Central

Gou, Jin-Ying; Miller, Lisa M.; Hou, Guichuan; Yu, Xiao-Hong; Chen, Xiao-Ya; Liu, Chang-Jun

2012-01-01

Pectin is a major component of the primary cell wall of higher plants. Some galacturonyl residues in the backbone of pectinaceous polysaccharides are often O-acetylated at the C-2 or C-3 position, and the resulting acetylesters change dynamically during the growth and development of plants. The processes involve both enzymatic acetylation and deacetylation. Through genomic sequence analysis, we identified a pectin acetylesterase (PAE1) from black cottonwood (Populus trichocarpa). Recombinant Pt PAE1 exhibited preferential activity in releasing the acetate moiety from sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectin in vitro. Overexpressing Pt PAE1 in tobacco (Nicotiana tabacum) decreased the level of acetyl esters of pectin but not of xylan. Deacetylation engendered differential changes in the composition and/or structure of cell wall polysaccharides that subsequently impaired the cellular elongation of floral styles and filaments, the germination of pollen grains, and the growth of pollen tubes. Consequently, plants overexpressing PAE1 exhibited severe male sterility. Furthermore, in contrast to the conventional view, PAE1-mediated deacetylation substantially lowered the digestibility of pectin. Our data suggest that pectin acetylesterase functions as an important structural regulator in planta by modulating the precise status of pectin acetylation to affect the remodeling and physiochemical properties of the cell wall's polysaccharides, thereby affecting cell extensibility. PMID:22247250

Acetylesterase-Mediated Deacetylation of Pectin Impairs Cell Elongation, Pollen Germination, and Plant Reproduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gou J. Y.; Liu C.; Miller, L. M.

Pectin is a major component of the primary cell wall of higher plants. Some galacturonyl residues in the backbone of pectinaceous polysaccharides are often O-acetylated at the C-2 or C-3 position, and the resulting acetylesters change dynamically during the growth and development of plants. The processes involve both enzymatic acetylation and deacetylation. Through genomic sequence analysis, we identified a pectin acetylesterase (PAE1) from black cottonwood (Populus trichocarpa). Recombinant Pt PAE1 exhibited preferential activity in releasing the acetate moiety from sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectin in vitro. Overexpressing Pt PAE1 in tobacco (Nicotiana tabacum) decreased the levelmore » of acetyl esters of pectin but not of xylan. Deacetylation engendered differential changes in the composition and/or structure of cell wall polysaccharides that subsequently impaired the cellular elongation of floral styles and filaments, the germination of pollen grains, and the growth of pollen tubes. Consequently, plants overexpressing PAE1 exhibited severe male sterility. Furthermore, in contrast to the conventional view, PAE1-mediated deacetylation substantially lowered the digestibility of pectin. Our data suggest that pectin acetylesterase functions as an important structural regulator in planta by modulating the precise status of pectin acetylation to affect the remodeling and physiochemical properties of the cell wall's polysaccharides, thereby affecting cell extensibility.« less

Effects of gamma-irradiation on cotyledon cell separation and pectin solubilisation in hard-to-cook cowpeas.

PubMed

Jombo, Talknice Z; Minnaar, Amanda; Taylor, John Rn

2018-03-01

Cowpeas stored under high temperature and humidity develop the hard-to-cook defect (HTC). This defect greatly increases cooking times and energy costs. To better understand the mechanisms involved in the HTC defect development, the effects of gamma-irradiation on cotyledon cellular structure and pectin solubility in two cowpea cultivars with different susceptibility to HTC defect were investigated. Gamma-irradiation decreased cotyledon cell wall thickness, increased cell size, and intercellular spaces in both cowpea cultivars and reduced cooking time of the less HTC susceptible cultivar. However, it did not reverse the HTC defect in the susceptible cultivar. Gamma-irradiation also increased the levels of cold water- and hot water-soluble pectin. The irradiation effects were thus mainly due to hydrolysis of pectin fractions in the cell walls. However, chelator-soluble pectin (CSP) solubility was not affected. As the cell wall changes brought about by gamma-irradiation were associated with pectin solubilisation, this supports the phytate-phytase-pectin theory as a major cause of the HTC defect. However, the non-reversal of the defect in HTC susceptible cowpeas and the absence of an effect on CSP indicate that other mechanisms are involved in HTC defect development in cowpeas, possibly the formation of alkali-soluble, ester bonded pectins. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Prebiotic potential of pectin and pectic oligosaccharides to promote anti-inflammatory commensal bacteria in the human colon.

PubMed

Chung, Wing Sun Faith; Meijerink, Marjolein; Zeuner, Birgitte; Holck, Jesper; Louis, Petra; Meyer, Anne S; Wells, Jerry M; Flint, Harry J; Duncan, Sylvia H

2017-11-01

Dietary plant cell wall carbohydrates are important in modulating the composition and metabolism of the complex gut microbiota, which can impact on health. Pectin is a major component of plant cell walls. Based on studies in model systems and available bacterial isolates and genomes, the capacity to utilise pectins for growth is widespread among colonic Bacteroidetes but relatively uncommon among Firmicutes. One Firmicutes species promoted by pectin is Eubacterium eligens. Eubacterium eligens DSM3376 utilises apple pectin and encodes a broad repertoire of pectinolytic enzymes, including a highly abundant pectate lyase of around 200 kDa that is expressed constitutively. We confirmed that certain Faecalibacterium prausnitzii strains possess some ability to utilise apple pectin and report here that F. prausnitzii strains in common with E. eligens can utilise the galacturonide oligosaccharides DP4 and DP5 derived from sugar beet pectin. Faecalibacterium prausnitzii strains have been shown previously to exert anti-inflammatory effects on host cells, but we show here for the first time that E. eligens strongly promotes the production of the anti-inflammatory cytokine IL-10 in in vitro cell-based assays. These findings suggest the potential to explore further the prebiotic potential of pectin and its derivatives to re-balance the microbiota towards an anti-inflammatory profile. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Liposomes-coated gold nanocages with antigens and adjuvants targeted delivery to dendritic cells for enhancing antitumor immune response.

PubMed

Liang, Ruijing; Xie, Jun; Li, Jun; Wang, Ke; Liu, Liping; Gao, Yujie; Hussain, Mubashir; Shen, Guanxin; Zhu, Jintao; Tao, Juan

2017-12-01

For nanovaccine-based cancer immunotherapy, dendritic cells (DCs) are one of the most powerful antigen presenting cells (APCs) that initiate and promote the maturation of antigen-specific cytotoxic T lymphocytes (e.g., CD8 + T cells) to induce the local and systemic antitumor immunity and further suppress the tumor metastasis and produce long-term protection against tumor. Thus, the activation and maturation of DCs is the prerequisite for efficient CD8 + T cell-based antitumor immune responses, which is considered as a primary and promising task for nanovaccine engineering. Herein, we introduce a versatile nanovaccine of liposomes-coated gold nanocages (Lipos-AuNCs) modified with DCs specific antibody aCD11c for targeted delivery of adjuvant MPLA and melanoma antigen peptide TRP2 to promote the activation and maturation of DCs, and enhance tumor specific T lymphocytes responses. Moreover, AuNCs accumulation and AuNCs-engulfed DCs migration to regional lymph nodes (RLNs) became real-time visualization through in vivo fluorescence and photoacoustic (PA) imaging to monitor the immunity process. In vivo experimental results demonstrated that the targeted antigen/adjuvants-loaded AuNCs exhibited enhanced antitumor immune response to inhibit tumor growth and metastasis in both B16-F10 prophylactic and lung metastasis models, which may act as a promising nanoplatform for antitumor immunotherapy and in vivo tracking. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fruit softening and pectin disassembly: an overview of nanostructural pectin modifications assessed by atomic force microscopy

PubMed Central

Paniagua, Candelas; Posé, Sara; Morris, Victor J.; Kirby, Andrew R.; Quesada, Miguel A.; Mercado, José A.

2014-01-01

Background One of the main factors that reduce fruit quality and lead to economically important losses is oversoftening. Textural changes during fruit ripening are mainly due to the dissolution of the middle lamella, the reduction of cell-to-cell adhesion and the weakening of parenchyma cell walls as a result of the action of cell wall modifying enzymes. Pectins, major components of fruit cell walls, are extensively modified during ripening. These changes include solubilization, depolymerization and the loss of neutral side chains. Recent evidence in strawberry and apple, fruits with a soft or crisp texture at ripening, suggests that pectin disassembly is a key factor in textural changes. In both these fruits, softening was reduced as result of antisense downregulation of polygalacturonase genes. Changes in pectic polymer size, composition and structure have traditionally been studied by conventional techniques, most of them relying on bulk analysis of a population of polysaccharides, and studies focusing on modifications at the nanostructural level are scarce. Atomic force microscopy (AFM) allows the study of individual polymers at high magnification and with minimal sample preparation; however, AFM has rarely been employed to analyse pectin disassembly during fruit ripening. Scope In this review, the main features of the pectin disassembly process during fruit ripening are first discussed, and then the nanostructural characterization of fruit pectins by AFM and its relationship with texture and postharvest fruit shelf life is reviewed. In general, fruit pectins are visualized under AFM as linear chains, a few of which show long branches, and aggregates. Number- and weight-average values obtained from these images are in good agreement with chromatographic analyses. Most AFM studies indicate reductions in the length of individual pectin chains and the frequency of aggregates as the fruits ripen. Pectins extracted with sodium carbonate, supposedly located within the primary cell wall, are the most affected. PMID:25063934

Combinatorial control of gene expression in Aspergillus niger grown on sugar beet pectin.

PubMed

Kowalczyk, Joanna E; Lubbers, Ronnie J M; Peng, Mao; Battaglia, Evy; Visser, Jaap; de Vries, Ronald P

2017-09-27

Aspergillus niger produces an arsenal of extracellular enzymes that allow synergistic degradation of plant biomass found in its environment. Pectin is a heteropolymer abundantly present in the primary cell wall of plants. The complex structure of pectin requires multiple enzymes to act together. Production of pectinolytic enzymes in A. niger is highly regulated, which allows flexible and efficient capture of nutrients. So far, three transcriptional activators have been linked to regulation of pectin degradation in A. niger. The L-rhamnose-responsive regulator RhaR controls the production of enzymes that degrade rhamnogalacturonan-I. The L-arabinose-responsive regulator AraR controls the production of enzymes that decompose the arabinan and arabinogalactan side chains of rhamnogalacturonan-II. The D-galacturonic acid-responsive regulator GaaR controls the production of enzymes that act on the polygalacturonic acid backbone of pectin. This project aims to better understand how RhaR, AraR and GaaR co-regulate pectin degradation. For that reason, we constructed single, double and triple disruptant strains of these regulators and analyzed their growth phenotype and pectinolytic gene expression in A. niger grown on sugar beet pectin.

Pectin-Lipid Self-Assembly: Influence on the Formation of Polyhydroxy Fatty Acids Nanoparticles

PubMed Central

Guzman-Puyol, Susana; Benítez, José Jesús; Domínguez, Eva; Bayer, Ilker Sefik; Cingolani, Roberto; Athanassiou, Athanassia; Heredia, Antonio; Heredia-Guerrero, José Alejandro

2015-01-01

Nanoparticles, named cutinsomes, have been prepared from aleuritic (9,10,16-trihidroxipalmitic) acid and tomato fruit cutin monomers (a mixture of mainly 9(10),16-dihydroxypalmitic acid (85%, w/w) and 16-hydroxyhexadecanoic acid (7.5%, w/w)) with pectin in aqueous solution. The process of formation of the nanoparticles of aleuritic acid plus pectin has been monitored by UV-Vis spectrophotometry, while their chemical and morphological characterization was analyzed by ATR-FTIR, TEM, and non-contact AFM. The structure of these nanoparticles can be described as a lipid core with a pectin shell. Pectin facilitated the formation of nanoparticles, by inducing their aggregation in branched chains and favoring the condensation between lipid monomers. Also, pectin determined the self-assembly of cutinsomes on highly ordered pyrolytic graphite (HOPG) surfaces, causing their opening and forming interconnected structures. In the case of cutin monomers, the nanoparticles are fused, and the condensation of the hydroxy fatty acids is strongly affected by the presence of the polysaccharide. The interaction of pectin with polyhydroxylated fatty acids could be related to an initial step in the formation of the plant biopolyester cutin. PMID:25915490

New bioactive and biobased product applications of pectin

USDA-ARS?s Scientific Manuscript database

Pectin is well known for its bioactive health-promoting properties and use in biobased products. Recent reports have demonstrated that pectin and pectic fractions have potential as prebiotics, prevent pathogenic bacterial adhesion, increase prostate specific antigen doubling time in patients with re...

Effects of pectin-containing diets on the hepatic macromolecular covalent binding of 2,6-dinitro-(/sup 3/H)toluene in Fischer-344 rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

deBethizy, J.D.; Sherrill, J.M.; Rickert, D.E.

1983-07-01

The influence of diets varying in pectin content on intestinal microfloral metabolic capacity of rats has been investigated as a possible mechanism for the alteration of toxicity of 2,6-dinitrotoluene (2,6-DNT) produced by these diets. Male F-344 rats were fed a purified diet (AIN-76A), AIN-76A plus 5% or 10% citrus pectin, or either of two cereal-based diets that vary in pectin content, NIH-07 or Purina Chow 5002. After 28 days, rats were given tritium-labeled 2,6-DNT (10 or 75 mg/kg po) and killed 12 hr later. Total hepatic macromolecular covalent binding (CVB) was determined by exhaustive extraction. The CVB of 2,6-DNT wasmore » found to be independent of diet at 10 mg/kg. However, at 75 mg/kg CVB was increased 40% by feeding 5% pectin in the purified diet and 90% by feeding 10% pectin in the purified diet. Animals fed Purina 5002 and NIH-07 had 135 and 150% higher CVB, respectively, than animals fed the purified diet alone and significantly greater CVB than animals fed the pectin supplemented diets. Elevated (two- to threefold) beta-glucuronidase and nitroreductase activities, microfloral enzymes proposed to be involved in the activation of 2,6-DNT to a toxicant, were found in the cecal contents of animals fed the pectin-containing diets which correlated with a two- to threefold increase in total number of cecal anaerobes. These results suggest that pectin-induced changes in microflora may enhance hepatoxicity after high doses of 2,6-DNT.« less

Process optimization and analysis of microwave assisted extraction of pectin from dragon fruit peel.

PubMed

Thirugnanasambandham, K; Sivakumar, V; Prakash Maran, J

2014-11-04

Microwave assisted extraction (MAE) technique was employed for the extraction of pectin from dragon fruit peel. The extracting parameters were optimized by using four-variable-three-level Box-Behnken design (BBD) coupled with response surface methodology (RSM). RSM analysis indicated good correspondence between experimental and predicted values. 3D response surface plots were used to study the interactive effects of process variables on extraction of pectin. The optimum extraction conditions for the maximum yield of pectin were power of 400 W, temperature of 45 °C, extracting time of 20 min and solid-liquid ratio of 24 g/mL. Under these conditions, 7.5% of pectin was extracted. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mapping structural and functional changes in esterase-treated pectin and characterizing enzyme mode of action

USDA-ARS?s Scientific Manuscript database

We hypothesized that pectin nanostructure can be enzymatically engineered with pectin methylesterase (PME) to tailor functionalities with improved consumer properties not available via conventional formulation or processing. Organoleptic qualities of processed and formulated foods are primary determ...

Characterization of the global structure of low methoxyl pectin in solution

USDA-ARS?s Scientific Manuscript database

Low methoxyl citrus pectin (LMP) and amidated low methoxyl pectin (LMAP) were characterized by high performance size exclusion chromatography (HPSEC) with online light scattering (LS), intrinsic viscosity ('w), differential refractive index (dRI) and ultra violet detection (UV), by amino acid anal...

Pectin gelation with chlorhexidine: Physico-chemical studies in dilute solutions.

PubMed

Lascol, Manon; Bourgeois, Sandrine; Guillière, Florence; Hangouët, Marie; Raffin, Guy; Marote, Pedro; Lantéri, Pierre; Bordes, Claire

2016-10-05

Low methoxyl pectin is known to gel with divalent cations (e.g. Ca(2+), Zn(2+)). In this study, a new way of pectin gelation in the presence of an active pharmaceutical ingredient, chlorhexidine (CX), was highlighted. Thus chlorhexidine interactions with pectin were investigated and compared with the well-known pectin/Ca(2+) binding model. Gelation mechanisms were studied by several physico-chemical methods such as zeta potential, viscosity, size measurements and binding isotherm was determined by Proton Nuclear Magnetic Resonance Spectroscopy ((1)H NMR). The binding process exhibited similar first two steps for both divalent ions: a stoichiometric monocomplexation of the polymer followed by a dimerization step. However, stronger interactions were observed between pectin and chlorhexidine. Moreover, the dimerization step occurred under stoichiometric conditions with chlorhexidine whereas non-stoichiometric conditions were involved with calcium ions. In the case of chlorhexidine, an additional intermolecular binding occurred in a third step. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aqueous extraction of pectin from sour orange peel and its preliminary physicochemical properties.

PubMed

Hosseini, Seyed Saeid; Khodaiyan, Faramarz; Yarmand, Mohammad Saeid

2016-01-01

Sour orange peel, a by-product of the fruit juice industry, was used as a source of pectin. The effects of temperature (75-95°C), time (30-90 min), and liquid-solid ratio (20-40, v/w) were investigated on yield, methoxylation degree (DE), and galacturonic acid content using a Box-Behnken design and response surface methodology. The highest extraction yield (17.95 ± 0.3%) was obtained at temperature of 95°C, time of 90 min, and liquid-solid ratio of 25 (v/w). The DE values for the pectin ranged from 17% to 30.5%, indicating that the pectin was low in methoxyle. The emulsifying activity of pectin extracted under optimal conditions was 45%. The emulsions were 86.6% stable at 4°C and 71.4% at 23°C after 30 days of storage. The pectin exhibited Newtonian flow at low concentrations (≤ 1.0%, w/v); as the concentration increased, pseudoplastic flow became dominant. Copyright © 2015 Elsevier B.V. All rights reserved.

On-line characterization using ultrasound of pectin hydrolysis catalyzed by the enzyme pectinmethylesterase

NASA Astrophysics Data System (ADS)

Aparicio, C.; Resa, P.; Sierra, C.; Elvira, L.

2012-12-01

The major problem in the fruit juice industry is associated with juice quality deterioration due to the cloud loss of juice concentrates by the enzymatic reaction of pectinmethylesterase enzyme (PME, EC 3.1.1.11). During pectin hydrolysis, pectin and water are transformed into polygalacturonic acid (pectate) and methanol by the action of PME. In this work, a low-intensity ultrasonic technique is used to monitor this enzymatic reaction, with PME both from orange peel and from Aspergillus niger. Changes in sound velocity during pectin hydrolysis (1% concentration of pectin, T = 30°C and pH = 4.5 and 7) with 0.25 ml of enzyme solution (PME) have been measured using a through-transmission technique. Sound velocity decreases as pectin is transformed into pectate and methanol and at the end of the process, the change in sound velocity reaches 0.3 m/s with PME from orange peel and 0.33 m/s with PME from Aspergillus niger.

Complexation of ferric oxide particles with pectins of different charge density.

PubMed

Milkova, Viktoria; Kamburova, Kamelia; Petkanchin, Ivana; Radeva, Tsetska

2008-09-02

The effect of polyelectrolyte charge density on the electrical properties and stability of suspensions of oppositely charged oxide particles is followed by means of electro-optics and electrophoresis. Variations in the electro-optical effect and the electrophoretic mobility are examined at conditions where fully ionized pectins of different charge density adsorb onto particles with ionizable surfaces. The charge neutralization point coincides with the maximum of particle aggregation in all suspensions. We find that the concentration of polyelectrolyte, needed to neutralize the particle charge, decreases with increasing charge density of the pectin. The most highly charged pectin presents an exception to this order, which is explained with a reduction of the effective charge density of this pectin due to condensation of counterions. The presence of condensed counterions, remaining bound to the pectin during its adsorption on the particle surface, is proved by investigation of the frequency behavior of the electro-optical effect at charge reversal of the particle surface.

Structural diversity of pectins isolated from the Styrian oil-pumpkin (Cucurbita pepo var. styriaca) fruit.

PubMed

Košťálová, Zuzana; Hromádková, Zdenka; Ebringerová, Anna

2013-03-01

To evaluate the seeded fruit biomass of the Styrian oil-pumpkin in view of its pectin component, a series of acidic polysaccharides were isolated by a six-step sequential extraction using hot water, EDTA, dilute HCl (twice) and dilute and stronger NaOH solutions. Chemical, physicochemical and spectroscopy analyses revealed that the first four fractions comprised partially methyl-esterified and acetylated pectins with varying proportions of rhamnogalacturonan regions ramified with galactose- and arabinose-containing side chains and showed considerable polymolecularity. The alkali-extracted polysaccharides contained lower amounts of pectins with homogalacturonan and arabinose-rich rhamnogalacturonan regions next to hemicelluloses prevailing in the last polysaccharide. Using (1)H-(13)C HSQC and HMBC spectroscopy, the resonances of free and methylesterified galacturonic acid residues in the purified acid-extracted pectin were unambiguously established and various diads formed by both residues identified. The results might serve as a basis for searching technological conditions to produce pectin from the oil-pumpkin fruit biomass. Copyright © 2012 Elsevier Ltd. All rights reserved.

Prior frozen storage enhances the effect of edible coatings against Listeria monocytogenes on cold-smoked salmon during subsequent refrigerated storage.

PubMed

Ye, M; Neetoo, H; Chen, H

2011-10-01

Listeria monocytogenes is a major safety concern for ready-to-eat foods. The overall objective of this study was to investigate whether prior frozen storage could enhance the efficacy of edible coatings against L. monocytogenes on cold-smoked salmon during subsequent refrigerated storage. A formulation consisting of sodium lactate (SL, 1·2-2·4%) and sodium diacetate (SD, 0·125-0·25%) or 2·5% Opti.Form (a commercial formulation of SL and SD) was incorporated into each of five edible coatings: alginate, κ-carrageenan, pectin, gelatin and starch. The coatings were applied onto the surface of cold-smoked salmon slices inoculated with L. monocytogenes at a level of 500 CFU cm⁻². In the first phase, the slices were first frozen at -18°C for 6 days and stored at 22°C for 6 days. Alginate, gelatin and starch appeared to be the most effective carriers. In the second phase, cold-smoked salmon slices were inoculated with L. monocytogenes, coated with alginate, gelatin or starch with or without the antimicrobials and stored frozen at -18°C for 12 months. Every 2 months, samples were removed from the freezer and kept at 4°C for 30 days. Prior frozen storage at -18°C substantially enhanced the antilisterial efficacy of the edible coatings with or without antimicrobials during the subsequent refrigerated storage. Plain coatings with ≥ 2 months frozen storage and antimicrobial edible coatings represent an effective intervention to inhibit the growth of L. monocytogenes on cold-smoked salmon. This study demonstrates the effectiveness of the conjunct application of frozen storage and edible coatings to control the growth of L. monocytogenes to enhance the microbiological safety of cold-smoked salmon. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Potentiometric titration for determining the composition and stability of metal(II) alginates and pectinates in aqueous solutions

NASA Astrophysics Data System (ADS)

Kaisheva, N. Sh.; Kaishev, A. Sh.

2015-07-01

The compositions and stabilities of Cu2+, Mn2+, Pb2+, Ca2+, Zn2+, Cd2+, Co2+, and Ni2+ alginates and pectinates are determined in aqueous solutions via titrimetry and potentiometry with calculations performed using Bjerrum's method, the curve intersection technique, and the equilibrium shift method. It is found that the interaction between Cu2+ and polyuronides is a stepwise process and, depending on the ligand concentration and the method of determination, Cu2+ alginate can be characterized by its ML, ML2, and ML3 compositions (where M is the metal ion and L is the structural unit of polyuronide) and stability constants logβ = 2.65, 5.00-5.70, and 7.18-7.80, respectively. The compositions of Cu2+ pectinates are ML and ML2 with logβ = 3.00 and 7.64-7.94, respectively. It is concluded that Pb2+, Ca2+, Mn2+, Zn2+, Cd2+, Co2+, and Ni2+ ions form only alginates and pectinates of ML2 composition with logβ values of 3.45 (Pb2+ alginate), 2.20 (Ca2+ alginate), 1.06 (Mn2+ alginate), 3.51 (Pb2+ pectinate), 2.35 (Ca2+ pectinate), and 1.24 (Mn2+ pectinate). The pectinates are shown to be more stable than the alginates, the most stable compounds being those formed by polyuronides and Cu2+. The least stable are those with Mn2+.

Non-covalent conjugation of cutinase from Fusarium sp. ICT SAC1 with pectin for enhanced stability: Process minutiae, kinetics, thermodynamics and structural study.

PubMed

Muley, Abhijeet B; Chaudhari, Sandeep A; Singhal, Rekha S

2017-09-01

Cutinase, a member of α/β-fold hydrolase family possess potentially diverse applications in several industrial processes and products. The present work aims towards thermo-stabilization of cutinase from novel source Fusarium sp. ICT SAC1 via non-covalent interaction with polysaccharides. Although all six polysaccharides chosen for study enhanced the thermal stability, pectin was found to be most promising. The interaction protocol for cutinase with pectin was optimized sequentially with respect to the ratio of enzyme to pectin, solution pH, and buffer strength. Cutinase-pectin conjugate under optimized conditions (1:12, pH-6.5, 50mM) showed enhanced thermal stability as evident from lower inactivation rate constant, higher half-life and D-value within the 40-55°C. A slender rise in K m and V max values and enhanced thermodynamic parameters of cutinase-pectin conjugate were observed after non-covalent interaction. Entropy values were 1.5-fold higher for cutinase-pectin conjugate at each temperature suggesting an upsurge in number of protein molecules in a transition activated state. Positive values of entropy for both forms of cutinase suggested a rise in disordered conformation. Noticeable conformational changes in cutinase after conjugation with pectin were confirmed by FTIR as well as fluorescence emission spectra. An increment in helix to turn conversion was observed in complexed cutinase vis-à-vis free cutinase. Copyright © 2017 Elsevier B.V. All rights reserved.

Cell-wall polysaccharide composition and glycanase activity of Silene vulgaris callus transformed with rolB and rolC genes.

PubMed

Günter, Elena A; Shkryl, Yury N; Popeyko, Oxana V; Veremeichik, Galina N; Bulgakov, Victor P

2015-03-15

The aim of this research is to investigate the effects of the Agrobacterium rhizogenes rol genes on the composition of cell-wall polysaccharides and glycanase activity in the campion callus. The expression of the rolC gene reduces the yield of campion pectin, while the expression of the rolB or rolC gene inhibits the volumetric production of both pectin and intracellular arabinogalactan. The rol genes are involved in regulating the activity of glycanases and esterases, thereby contributing to the modification of polysaccharide structures, their molecular weight (Mw) and the degree of pectin methyl esterification (DE). The increase in pectin arabinose residue appears to be connected to a decrease in intracellular and extracellular α-l-arabinofuranosidase activity in transgenic campion calluses. In transgenic calluses expressing the rolB and rolC genes, the increase in pectin galactose residue is likely due to a decrease in β-galactosidase activity. The decrease in the Mw of pectin and its d-galacturonic acid content appears to be connected to an increase in extracellular polygalacturonase activity. Finally, the increase in pectinesterase activity causes a decrease in the DE of pectin. Thus, the expression of rolB and rolC genes in campion callus has a considerable effect on pectin's sugar composition, DE and Mw, while it appears to have an insignificant influence on intracellular and extracellular arabinogalactans. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ultrasound-assisted extraction of pectins from grape pomace using citric acid: a response surface methodology approach.

PubMed

Minjares-Fuentes, R; Femenia, A; Garau, M C; Meza-Velázquez, J A; Simal, S; Rosselló, C

2014-06-15

An ultrasound-assisted procedure for the extraction of pectins from grape pomace with citric acid as the extracting agent was established. A Box-Behnken design (BBD) was employed to optimize the extraction temperature (X1: 35-75°C), extraction time (X2: 20-60 min) and pH (X3: 1.0-2.0) to obtain a high yield of pectins with high average molecular weight (MW) and degree of esterification (DE) from grape pomace. Analysis of variance showed that the contribution of a quadratic model was significant for the pectin extraction yield and for pectin MW whereas the DE of pectins was more influenced by a linear model. An optimization study using response surface methodology was performed and 3D response surfaces were plotted from the mathematical model. According to the RSM model, the highest pectin yield (∼32.3%) can be achieved when the UAE process is carried out at 75°C for 60 min using a citric acid solution of pH 2.0. These pectic polysaccharides, composed mainly by galacturonic acid units (<97% of total sugars), have an average MW of 163.9 kDa and a DE of 55.2%. Close agreement between experimental and predicted values was found. These results suggest that ultrasound-assisted extraction could be a good option for the extraction of functional pectins with citric acid from grape pomace at industrial level. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of microparticles prepared by emulsion method from pectin and protein

USDA-ARS?s Scientific Manuscript database

In this study, pectin was extracted from apple peel and formulated into microparticles in combination with zein, an edible food protein. The physical, chemical, and structural properties of the resultant pectin structures were evaluated. The resultant microparticles were also examined in vitro for c...

Biosorption properties of citrus peel derived oligogalacturonides, enzyme-modified pectin and peel hydrolysis residues

USDA-ARS?s Scientific Manuscript database

Data is presented on the biosorption properties of modified pectins and pectin fragments using lead as a model cation. Samples tested for their sorption capacity are Narrow-Range Size-Classes of galacturonic acid oligomers, well characterized homogalacturonan demethylations series produced at pH 7....

Structure of a pectin methylesterase from Yersinia enterocolitica.

PubMed

Boraston, Alisdair B; Abbott, D Wade

2012-02-01

Pectin methylesterases (PMEs) are family 8 carbohydrate esterases (CE8s) which remove the methyl group from methylesterified galacturonic acid (GalA) residues within pectin. Although the role of pectinases such as PMEs within dedicated phytopathogens has been well established, the significance of homologous enzymes found within the genomes of human enteropathogens remains to be determined. Presented here is the low-resolution (3.5 Å) structure of the CE8 from Yersinia enterocolitica (YeCE8). The high degree of structural conservation in the topology of the active-site cleft and catalytic apparatus that is shared with a characterized PME from a bacterial phytopathogen (i) indicates that YeCE8 is active on methylated pectin and (ii) highlights a more prominent role for pectin utilization in Yersinia than in other enteropathogenic species.

Pectin functionalised by fatty acids: Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopic characterisation

NASA Astrophysics Data System (ADS)

Kamnev, Alexander A.; Calce, Enrica; Tarantilis, Petros A.; Tugarova, Anna V.; De Luca, Stefania

2015-01-01

Chemically modified pectin derivatives obtained by partial esterification of its hydroxyl moieties with fatty acids (FA; oleic, linoleic and palmitic acids), as well as the initial apple peel pectin were comparatively characterised using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Characteristic changes observed in DRIFT spectra in going from pectin to its FA esters are related to the corresponding chemical modifications. Comparing the DRIFT spectra with some reported data on FTIR spectra of the same materials measured in KBr or NaCl matrices has revealed noticeable shifts of several polar functional groups both in pectin and in its FA-esterified products induced by the halide salts. The results obtained have implications for careful structural analyses of biopolymers with hydrophilic functional groups by means of different FTIR spectroscopic methodologies.

Cacao pod husks as a source of low-methoxyl, highly acetylated pectins able to gel in acidic media.

PubMed

Vriesmann, Lúcia Cristina; de Oliveira Petkowicz, Carmen Lúcia

2017-08-01

Cacao pod husks, the main by-product from cocoa production, have been investigated for pectin isolation. In the present study, the rheological properties of two low-methoxyl (LM) pectins isolated from cacao pod husks using different extraction conditions were evaluated. One pectin was obtained from optimized conditions employing aqueous nitric acid as an extractant, and the other one was extracted with boiling water. Pectin gels (0.99% galacturonic acid equivalent, w/w) were prepared at pH 2.5-3.0 in the presence of 60% sucrose (w/w) and subjected to rheological analysis. Dynamic oscillatory experiments at 25°C indicated that better gels were obtained at the lowest pH (2.5). Steady shear measurements revealed a shear-thinning behavior. The apparent viscosities of the samples increased as pH decreased. Gelation with calcium ions was not observed for either of the highly acetylated LM pectins analyzed. The rheological analysis results showed that despite their high acetyl content, LM pectins extracted by different methods from cacao pod husks were able to form gels at low pH under reduced water activity, suggesting a possible application in acidic products. Copyright © 2017 Elsevier B.V. All rights reserved.

Enzymatic modification of a model homogalacturonan with the thermally tolerant pectin methylesterase from Citrus: 1. Nanostructural characterization, enzyme mode of action, and effect of pH.

PubMed

Cameron, Randall G; Luzio, Gary A; Vasu, Prasanna; Savary, Brett J; Williams, Martin A K

2011-03-23

Methyl ester distribution in pectin homogalacturonan has a major influence on functionality. Enzymatic engineering of the pectin nanostructure for tailoring functionality can expand the role of pectin as a food-formulating agent and the use of in situ modification in prepared foods. We report on the mode of action of a unique citrus thermally tolerant pectin methylesterase (TT-PME) and the nanostructural modifications that it produces. The enzyme was used to produce a controlled demethylesterification series from a model homogalacturonan. Oligogalacturonides released from the resulting demethylesterified blocks introduced by TT-PME using a limited endopolygalacturonase digestion were separated and quantified by high-pressure anion-exchange chromatography (HPAEC) coupled to an evaporative light-scattering detector (ELSD). The results were consistent with the predictions of a numerical simulation, which assumed a multiple-attack mechanism and a degree of processivity ∼10, at both pH 4.5 and 7.5. The average demethylesterified block size (0.6-2.8 nm) and number of average-sized blocks per molecule (0.8-1.9) differed, depending upon pH of the enzyme treatment. The mode of action of this enzyme and consequent nanostructural modifications of pectin differ from a previously characterized citrus salt-independent pectin methylesterase (SI-PME).

Pectin methylesterase and its proteinaceous inhibitor: a review.

PubMed

Jolie, Ruben P; Duvetter, Thomas; Van Loey, Ann M; Hendrickx, Marc E

2010-12-10

Pectin methylesterase (PME) catalyses the demethoxylation of pectin, a major plant cell wall polysaccharide. Through modification of the number and distribution of methyl-esters on the pectin backbone, PME affects the susceptibility of pectin towards subsequent (non-) enzymatic conversion reactions (e.g., pectin depolymerisation) and gel formation, and, hence, its functionality in both plant cell wall and pectin-containing food products. The enzyme plays a key role in vegetative and reproductive plant development in addition to plant-pathogen interactions. In addition, PME action can impact favourably or deleteriously on the structural quality of plant-derived food products. Consequently, PME and also the proteinaceous PME inhibitor (PMEI) found in several plant species and specifically inhibiting plant PMEs are highly relevant for plant biologists as well as for food technologists and are intensively studied in both fields. This review paper provides a structured, comprehensive overview of the knowledge accumulated over the years with regard to PME and PMEI. Attention is paid to both well-established and novel data concerning (i) their occurrence, polymorphism and physicochemical properties, (ii) primary and three-dimensional protein structures, (iii) catalytic and inhibitory activities, (iv) physiological roles in vivo and (v) relevance of (endogenous and exogenous) enzyme and inhibitor in the (food) industry. Remaining research challenges are indicated. Copyright © 2010 Elsevier Ltd. All rights reserved.

Involvement of Fungal Pectin Methylesterase Activity in the Interaction Between Fusarium graminearum and Wheat.

PubMed

Sella, Luca; Castiglioni, Carla; Paccanaro, Maria Chiara; Janni, Michela; Schäfer, Wilhelm; D'Ovidio, Renato; Favaron, Francesco

2016-04-01

The genome of Fusarium graminearum, the causal agent of Fusarium head blight of wheat, contains two putative pectin methylesterase (PME)-encoding genes. However, when grown in liquid culture containing pectin, F. graminearum produces only a single PME, which was purified and identified. Its encoding gene, expressed during wheat spike infection, was disrupted by targeted homologous recombination. Two Δpme mutant strains lacked PME activity but were still able to grow on highly methyl-esterified pectin even though their polygalacturonase (PG) activity showed a reduced capacity to depolymerize this substrate. The enzymatic assays performed with purified F. graminearum PG and PME demonstrated an increase in PG activity in the presence of PME on highly methyl-esterified pectin. The virulence of the mutant strains was tested on Triticum aestivum and Triticum durum spikes, and a significant reduction in the percentage of symptomatic spikelets was observed between 7 and 12 days postinfection compared with wild type, demonstrating that the F. graminearum PME contributes to fungal virulence on wheat by promoting spike colonization in the initial and middle stages of infection. In contrast, transgenic wheat plants with increased levels of pectin methyl esterification did not show any increase in resistance to the Δpme mutant, indicating that the infectivity of the fungus relies only to a certain degree on pectin degradation.

Formulation and optimization of zinc-pectinate beads for the controlled delivery of resveratrol.

PubMed

Das, Surajit; Ng, Ka-Yun; Ho, Paul C

2010-06-01

Preventive and therapeutic efficacies of resveratrol on several lower gastrointestinal (GI) diseases (e.g., colorectal cancer, colitis) are well documented. To overcome the problems due to its rapid absorption and metabolism at the upper GI tract, a delayed release formulation of resveratrol was designed to treat these lower GI diseases. The current study aimed to develop a delayed release formulation of resveratrol as multiparticulate pectinate beads by varying different formulation parameters. Zinc-pectinate (Zn-pectinate) beads exhibited better delayed drug release pattern than calcium-pectinate (Ca-pectinate) beads. The effects of the formulation parameters were investigated on shape, size, Zn content, moisture content, drug encapsulation efficiency, swelling-erosion, and resveratrol retention pattern of the formulated beads. Upon optimization of the formulation parameters in relative to the drug release profiles, the optimized beads were further subjected to morphological, chemical interaction, enzymatic degradation, and stability studies. Almost all prepared beads were spherical with approximately 1 mm diameter and efficiently encapsulated resveratrol. The formulation parameters revealed great influence on resveratrol retention and swelling-erosion behavior. In most of the cases, the drug release data more appropriately fitted with zero-order equation. This study demonstrates that the optimized Zn-pectinate beads can encapsulate very high amount of resveratrol and can be used as delayed release formulation of resveratrol.

Effect of sucrose and pectin addition on physical, chemical, thermal and rheological properties of frozen/thawed pineapple pulps

NASA Astrophysics Data System (ADS)

Conceição, Márcia Cavalcante; Fernandes, Tatiana Nunes; Prado, Mônica Elisabeth Torres; de Resende, Jaime Vilela

2012-09-01

Pectin (0-1.0 g/100 mL) and sucrose (0-20 g/100 mL) were added to pineapple pulp to improve their rheological properties, thermal properties and stability after freezing and thawing processes. The properties of the mixes were characterized before and after freezing and thawing. Samples were frozen at -20°C, and the freeze concentration was evaluated every 60 min. The thawing rate was evaluated at 19°C and quantified by photographic editing and image analysis software. The thawing rates and values for the freeze concentration were leveled out at pectin concentrations above 0.5 g/100 mL pectin, which indicated that pectin functions to maintain structural homogeneity during freezing. In the thawed samples, the plastic viscosity values were leveled out from pectin concentrations (0.25-0.75 g/100 mL) as the sucrose concentration increased when compared to unfrozen samples. The differences between the rheological parameters of the unfrozen and frozen/thawed pulps, the higher yield stress values after thawing were attributed to the size of suspended particles in the pulp. Applications can specify formulations of frozen products containing pectin, where these properties can be handled after thawing the product.

Sheddable Coatings for Long-Circulating Nanoparticles

PubMed Central

Romberg, Birgit; Hennink, Wim E.

2007-01-01

Nanoparticles, such as liposomes, polymeric micelles, lipoplexes and polyplexes are frequently studied as targeted drug carrier systems. The ability of these particles to circulate in the bloodstream for a prolonged period of time is often a prerequisite for successful targeted delivery. To achieve this, hydrophilic ‘stealth’ polymers, such as poly(ethylene glycol) (PEG), are used as coating materials. Such polymers shield the particle surface and thereby reduce opsonization by blood proteins and uptake by macrophages of the mononuclear phagocyte system. Yet, after localizing in the pathological site, nanoparticles should deliver their contents in an efficient manner to achieve a sufficient therapeutic response. The polymer coating, however, may hinder drug release and target cell interaction and can therefore be an obstacle in the realization of the therapeutic response. Attempts have been made to enhance the therapeutic efficacy of sterically stabilized nanoparticles by means of shedding, i.e. a loss of the coating after arrival at the target site. Such an ‘unmasking’ process may facilitate drug release and/or target cell interaction processes. This review presents an overview of the literature regarding different shedding strategies that have been investigated for the preparation of sterically stabilized nanoparticulates. Detach mechanisms and stimuli that have been used are described. PMID:17551809

Convective polymer assembly for the deposition of nanostructures and polymer thin films on immobilized particles.

PubMed

Richardson, Joseph J; Björnmalm, Mattias; Gunawan, Sylvia T; Guo, Junling; Liang, Kang; Tardy, Blaise; Sekiguchi, Shota; Noi, Ka Fung; Cui, Jiwei; Ejima, Hirotaka; Caruso, Frank

2014-11-21

We report the preparation of polymer particles via convective polymer assembly (CPA). Convection is used to move polymer solutions and cargo through an agarose gel that contains immobilized template particles. This method both coats and washes the particles in a process that is amenable to automation, and does not depend on passive diffusion or electrical currents, thus facilitating incorporation of fragile and nanoscale objects, such as liposomes and gold nanoparticles, into the thin polymer films. Template dissolution leads to the formation of stable polymer particles and capsules.

Fruit softening and pectin disassembly: an overview of nanostructural pectin modifications assessed by atomic force microscopy.

PubMed

Paniagua, Candelas; Posé, Sara; Morris, Victor J; Kirby, Andrew R; Quesada, Miguel A; Mercado, José A

2014-10-01

One of the main factors that reduce fruit quality and lead to economically important losses is oversoftening. Textural changes during fruit ripening are mainly due to the dissolution of the middle lamella, the reduction of cell-to-cell adhesion and the weakening of parenchyma cell walls as a result of the action of cell wall modifying enzymes. Pectins, major components of fruit cell walls, are extensively modified during ripening. These changes include solubilization, depolymerization and the loss of neutral side chains. Recent evidence in strawberry and apple, fruits with a soft or crisp texture at ripening, suggests that pectin disassembly is a key factor in textural changes. In both these fruits, softening was reduced as result of antisense downregulation of polygalacturonase genes. Changes in pectic polymer size, composition and structure have traditionally been studied by conventional techniques, most of them relying on bulk analysis of a population of polysaccharides, and studies focusing on modifications at the nanostructural level are scarce. Atomic force microscopy (AFM) allows the study of individual polymers at high magnification and with minimal sample preparation; however, AFM has rarely been employed to analyse pectin disassembly during fruit ripening. In this review, the main features of the pectin disassembly process during fruit ripening are first discussed, and then the nanostructural characterization of fruit pectins by AFM and its relationship with texture and postharvest fruit shelf life is reviewed. In general, fruit pectins are visualized under AFM as linear chains, a few of which show long branches, and aggregates. Number- and weight-average values obtained from these images are in good agreement with chromatographic analyses. Most AFM studies indicate reductions in the length of individual pectin chains and the frequency of aggregates as the fruits ripen. Pectins extracted with sodium carbonate, supposedly located within the primary cell wall, are the most affected. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

LEUNIG_HOMOLOG transcriptional co-repressor mediates aluminium sensitivity through PECTIN METHYLESTERASE46-modulated root cell wall pectin methylesterification in Arabidopsis.

PubMed

Geng, Xiaoyu; Horst, Walter J; Golz, John F; Lee, Joanne E; Ding, Zhaojun; Yang, Zhong-Bao

2017-05-01

A major factor determining aluminium (Al) sensitivity in higher plants is the binding of Al to root cell walls. The Al binding capacity of cell walls is closely linked to the extent of pectin methylesterification, as the presence of methyl groups attached to the pectin backbone reduces the net negative charge of this polymer and hence limits Al binding. Despite recent progress in understanding the molecular basis of Al resistance in a wide range of plants, it is not well understood how the methylation status of pectin is mediated in response to Al stress. Here we show in Arabidopsis that mutants lacking the gene LEUNIG_HOMOLOG (LUH), a member of the Groucho-like family of transcriptional co-repressor, are less sensitive to Al-mediated repression of root growth. This phenotype is correlated with increased levels of methylated pectin in the cell walls of luh roots as well as altered expression of cell wall-related genes. Among the LUH-repressed genes, PECTIN METHYLESTERASE46 (PME46) was identified as reducing Al binding to cell walls and hence alleviating Al-induced root growth inhibition by decreasing PME enzyme activity. seuss-like2 (slk2) mutants responded to Al in a similar way as luh mutants suggesting that a LUH-SLK2 complex represses the expression of PME46. The data are integrated into a model in which it is proposed that PME46 is a major inhibitor of pectin methylesterase activity within root cell walls. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

The nanostructural characterization of strawberry pectins in pectate lyase or polygalacturonase silenced fruits elucidates their role in softening.

PubMed

Posé, Sara; Kirby, Andrew R; Paniagua, Candelas; Waldron, Keith W; Morris, Victor J; Quesada, Miguel A; Mercado, José A

2015-11-05

To ascertain the role of pectin disassembly in fruit softening, chelated- (CSP) and sodium carbonate-soluble (SSP) pectins from plants with a pectate lyase, FaplC, or a polygalacturonase, FaPG1, downregulated by antisense transformation were characterized at the nanostructural level. Fruits from transgenic plants were firmer than the control, although FaPG1 suppression had a greater effect on firmness. Size exclusion chromatography showed that the average molecular masses of both transgenic pectins were higher than that of the control. Atomic force microscopy analysis of pectins confirmed the higher degree of polymerization as result of pectinase silencing. The mean length values for CSP chains increased from 84 nm in the control to 95.5 and 101 nm, in antisense FaplC and antisense FaPG1 samples, respectively. Similarly, SSP polyuronides were longer in transgenic fruits (61, 67.5 and 71 nm, in the control, antisense FaplC and antisense FaPG1 samples, respectively). Transgenic pectins showed a more complex structure, with a higher percentage of branched chains than the control, especially in the case of FaPG1 silenced fruits. Supramolecular pectin aggregates, supposedly formed by homogalacturonan and rhamnogalacturonan I, were more frequently observed in antisense FaPG1 samples. The larger modifications in the nanostructure of pectins in FaPG1 silenced fruits when compared with antisense pectate lyase plants correlate with the higher impact of polygalacturonase silencing on reducing strawberry fruit softening. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pectin-rich biomass as feedstock for fuel ethanol production.

PubMed

Edwards, Meredith C; Doran-Peterson, Joy

2012-08-01

The USA has proposed that 30 % of liquid transportation fuel be produced from renewable resources by 2030 (Perlack and Stokes 2011). It will be impossible to reach this goal using corn kernel-based ethanol alone. Pectin-rich biomass, an under-utilized waste product of the sugar and juice industry, can augment US ethanol supplies by capitalizing on this already established feedstock. Currently, pectin-rich biomass is sold (at low value) as animal feed. This review focuses on the three most studied types of pectin-rich biomass: sugar beet pulp, citrus waste and apple pomace. Fermentations of these materials have been conducted with a variety of ethanologens, including yeasts and bacteria. Escherichia coli can ferment a wide range of sugars including galacturonic acid, the primary component of pectin. However, the mixed acid metabolism of E. coli can produce unwanted side products. Saccharomyces cerevisiae cannot naturally ferment galacturonic acid nor pentose sugars but has a homoethanol pathway. Erwinia chrysanthemi is capable of degrading many of the cell wall components of pectin-rich materials, including pectin. Klebsiella oxytoca can metabolize a diverse array of sugars including cellobiose, one degradation product of cellulose. However, both E. chrysanthemi and K. oxytoca produce side products during fermentation, similar to E. coli. Using pectin-rich residues from industrial processes is beneficial because the material is already collected and partially pretreated to facilitate enzymatic deconstruction of the plant cell walls. Using biomass already produced for other purposes is an attractive practice because fewer greenhouse gases (GHG) will be anticipated from land-use changes.

A tale of two pectins: Diverse fine structures can result from identical processive PME treatments on similar high DM subtrates

USDA-ARS?s Scientific Manuscript database

The effects of a processive pectin-methylesterase treatment on two different pectins, both possessing a high degree of methylesterification, were investigated. While the starting samples were purportedly very similar in fine structure, and even though the sample-averaged degree of methylesterificati...

Effect of substituted gelling agents from pomegranate peel on colour, textural and sensory properties of pomegranate jam.

PubMed

Abid, Mouna; Yaich, Héla; Hidouri, Hayfa; Attia, Hamadi; Ayadi, M A

2018-01-15

A series of pomegranate jams were prepared from a Tunisian ecotype (Tounsi) with different amounts of sugar (10, 20 and 30%) and low-methoxylated pectin (0.2, 0.7 and 1.2%). The most appreciated formulation was that contaning 30% sugars and 0.2% pectin. Then, commercial pectin was substituted by other gelling agents (pomegranate peel powders dried at 50°C vs lyophilized, pectin and fibre extracted from pomegranate peel) for the preparation of pomegranate peel-based jams. The elaborated jams were evaluated for physichochemical, colour, texture and sensory characteristics. Results revealed that the jam (JPP2) elaborated with 0.2% pectin extracted from pomegranate peel exhibited similar overall acceptability to that prepared with commercial pectin. However, it was more acceptable than other pomegranate peel-based jams, which was related to a better appreciation of sweetness and colour. According to the colour and texture measurements, this sample (JPP2) was more reddish and less firm than other samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

L-Altruronic acid formed by epimerization of D-galacturonic acid methyl esters during saponification of citrus pectin.

PubMed

Zhan, D; Qiu, F; Mort, A J

2001-02-15

While searching for oligosaccharides containing rhamnose residues in the endopolygalacturonase (EPG) digest of saponified citrus pectin, we found several oligomers containing, in addition to galacturonic acid, a sugar previously unreported in pectin. The 1- and 2-D 1H NMR spectra of the oligosaccharides were consistent with the sugar being a uronic acid with its 2- and 3-hydroxyls being axial and 4-hydroxyl being equatorial. MALDI-TOF mass spectrometry indicated that the oligomers consisted solely of uronic acids. Reduction of the uronic acids in the oligosaccharides converted them to galactose and altrose. The altrose was found to be the L enantiomer by comparison of its trimethylsilyl (-)-2-butyl glycosides to those of authentic D-altrose and a racemic mixture. The sugar was not found in oligosaccharides prepared from EPG digestion of citrus pectin deesterified with pectin methylesterase rather than saponification. Thus, it appears that during saponification, a small proportion of the methylesterified galacturonic acid residues in pectins is epimerized at C-5 leading to formation of L-altruronic acid residues.

Pectin from Opuntia ficus indica: Optimization of microwave-assisted extraction and preliminary characterization.

PubMed

Lefsih, Khalef; Giacomazza, Daniela; Dahmoune, Farid; Mangione, Maria Rosalia; Bulone, Donatella; San Biagio, Pier Luigi; Passantino, Rosa; Costa, Maria Assunta; Guarrasi, Valeria; Madani, Khodir

2017-04-15

Optimization of microwave-assisted extraction (MAE) of water-soluble pectin (WSP) from Opuntia ficus indica cladodes was performed using Response Surface Methodology. The effect of extraction time (X 1 ), microwave power (X 2 ), pH (X 3 ) and solid-to-liquid ratio (X 4 ) on the extraction yield was examined. The optimum conditions of MAE were as follows: X 1 =2.15min; X 2 =517W; X 3 =2.26 and X 4 =2g/30.6mL. The maximum obtained yield of pectin extraction was 12.57%. Total carbohydrate content of WSP is about 95.5% including 34.4% of Galacturonic acid. Pectin-related proteins represent only the 0.66% of WSP mass. HPSEC and light scattering analyses reveal that WSP is mostly constituted of high molecular pectin and FTIR measurements show that the microwave treatment does not alter the chemical structure of WSP, in which Galacturonic acid content and yield are 34.4% and 4.33%, respectively. Overall, application of MAE can give rise to high quality pectin. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous measurement of two enzyme activities using infrared spectroscopy: A comparative evaluation of PARAFAC, TUCKER and N-PLS modeling.

PubMed

Baum, Andreas; Hansen, Per Waaben; Meyer, Anne S; Mikkelsen, Jørn Dalgaard

2013-08-06

Enzymes are used in many processes to release fermentable sugars for green production of biofuel, or the refinery of biomass for extraction of functional food ingredients such as pectin or prebiotic oligosaccharides. The complex biomasses may, however, require a multitude of specific enzymes which are active on specific substrates generating a multitude of products. In this paper we use the plant polymer, pectin, to present a method to quantify enzyme activity of two pectolytic enzymes by monitoring their superimposed spectral evolutions simultaneously. The data is analyzed by three chemometric multiway methods, namely PARAFAC, TUCKER3 and N-PLS, to establish simultaneous enzyme activity assays for pectin lyase and pectin methyl esterase. Correlation coefficients Rpred(2) for prediction test sets are 0.48, 0.96 and 0.96 for pectin lyase and 0.70, 0.89 and 0.89 for pectin methyl esterase, respectively. The retrieved models are compared and prediction test sets show that especially TUCKER3 performs well, even in comparison to the supervised regression method N-PLS. Copyright © 2013 Elsevier B.V. All rights reserved.

Partial demethylation of oligogalacturonides by pectin methyl esterase 1 is required for eliciting defence responses in wild strawberry (Fragaria vesca).

PubMed

Osorio, Sonia; Castillejo, Cristina; Quesada, Miguel A; Medina-Escobar, Nieves; Brownsey, Geoff J; Suau, Rafael; Heredia, Antonio; Botella, Miguel A; Valpuesta, Victoriano

2008-04-01

In addition to the role of the cell wall as a physical barrier against pathogens, some of its constituents, such as pectin-derived oligogalacturonides (OGA), are essential components for elicitation of defence responses. To investigate how modifications of pectin alter defence responses, we expressed the fruit-specific Fragaria x ananassa pectin methyl esterase FaPE1 in the wild strawberry Fragaria vesca. Pectin from transgenic ripe fruits differed from the wild-type with regard to the degree and pattern of methyl esterification, as well as the average size of pectin polymers. Purified oligogalacturonides from the transgenic fruits showed a reduced degree of esterification compared to oligogalacturonides from wild-type fruits. This reduced esterification is necessary to elicit defence responses in strawberry. The transgenic F. vesca lines had constitutively activated pathogen defence responses, resulting in higher resistance to the necrotropic fungus Botrytis cinerea. Further studies in F. vesca and Nicotiana benthamiana leaves showed that the elicitation capacity of the oligogalacturonides is more specific than previously envisaged.

Kinetics of microwave assisted extraction of pectin from Balinese orange peel using Pseudo-homogeneous model

NASA Astrophysics Data System (ADS)

Megawati, Wulansarie, Ria; Faiz, Merisa Bestari; Adi, Susatyo; Sammadikun, Waliyuddin

2018-03-01

The objective of this work was to study the homogeneous kinetics of pectin extraction of Balinese orange peel conducted using Microwave Assisted Extraction (MAE). The experimental data showed that the power increases (180 to 600 W), so that the extraction yield of pectin also increases (12.2 to 30.6 % w/w). Moreover, the extraction time is longer (10, 15, and 20 min) the yield of pectin increases (8.8, 20.2, and 40.5). At time after of 20 min (25 and 30 min), the yield starts to decrease (36.6 and 22.9). This phenomena shows pectin degradation. Therefore, pectin extraction is a series reaction, i.e. extraction and degradation. The calculation result showed that pseudo series homogeneous model can quantitatively describe the extraction kinetics. The kinetic constants can be expressed by Arrhenius equation with the frequency factors of 1.58 × 105 and 2.29 × 105 1/min, while the activation energies are 64,350 and 56,571 J/mole for extraction and degradation, respectively.

Analysis and optimization of flocculation activity and turbidity reduction in kaolin suspension using pectin as a biopolymer flocculant.

PubMed

Ho, Y C; Norli, I; Alkarkhi, Abbas F M; Morad, N

2009-01-01

The performance of pectin in turbidity reduction and the optimum condition were determined using Response Surface Methodology (RSM). The effect of pH, cation's concentration, and pectin's dosage on flocculating activity and turbidity reduction was investigated at three levels and optimized by using Box-Behnken Design (BBD). Coagulation and flocculation process were assessed with a standard jar test procedure with rapid and slow mixing of a kaolin suspension (aluminium silicate), at 150 rpm and 30 rpm, respectively, in which a cation e.g. Al(3+), acts as coagulant, and pectin acts as the flocculant. In this research, all factors exhibited significant effect on flocculating activity and turbidity reduction. The experimental data and model predictions well agreed. From the 3D response surface graph, maximum flocculating activity and turbidity reduction are in the region of pH greater than 3, cation concentration greater than 0.5 mM, and pectin dosage greater than 20 mg/L, using synthetic turbid wastewater within the range. The flocculating activity for pectin and turbidity reduction in wastewater is at 99%.

High humidity hot air impingement blanching (HHAIB) enhances drying rate and softens texture of apricot via cell wall pectin polysaccharides degradation and ultrastructure modification.

PubMed

Deng, Li-Zhen; Mujumdar, A S; Yang, Xu-Hai; Wang, Jun; Zhang, Qian; Zheng, Zhi-An; Gao, Zhen-Jiang; Xiao, Hong-Wei

2018-09-30

The effects of high humidity hot air impingement blanching (HHAIB) over a range of application times (30, 60, 90, and 120 s) on drying characteristics, hardness, cell wall pectin fractions contents and nanostructure, as well ultrastructure of apricot were investigated. Results showed that HHAIB reduced drying time and decreased the hardness of apricot by 20.7%-34.5% and 46.57%-71.89%, respectively. The water-soluble pectin (WSP) contents increased after blanching, while the contents of chelate-soluble pectin (CSP) and sodium-carbonate-soluble pectin (NSP) decreased significantly (P < 0.05). The hardness and drying time were found to correlate inversely with the WSP content, but positively with CSP and NSP contents. Atomic force microscopy (AFM) detection showed the decomposition and degradation of pectin fractions during blanching. Additionally, transmission electron microscopy (TEM) observation indicated that the cell wall structure was degraded and middle lamella integrity was destroyed by blanching. Copyright © 2018 Elsevier Ltd. All rights reserved.

Alteration of cell wall polysaccharides through transgenic expression of UDP-Glc 4-epimerase-encoding genes in potato tubers.

PubMed

Huang, Jie-Hong; Kortstee, Anne; Dees, Dianka C T; Trindade, Luisa M; Schols, Henk A; Gruppen, Harry

2016-08-01

Uridine diphosphate (UDP)-glucose 4-epimerase (UGE) catalyzes the conversion of UDP-glucose to UDP-galactose. Cell wall materials from the cv. Kardal (wild-type, background) and two UGE transgenic lines (UGE 45-1 and UGE 51-16) were isolated and fractionated. The galactose (Gal) content (mg/100g tuber) from UGE 45-1 transgenic line was 38% higher than that of wild-type, and resulted in longer pectin side chains. The Gal content present in UGE 51-16 was 17% lower than that of wild-type, although most pectin populations maintained the same level of Gal. Both UGE transgenic lines showed unexpectedly a decrease in acetylation and an increase in methyl-esterification of pectin. Both UGE transgenic lines showed similar proportions of homogalacturonan and rhamnogalacturonan I within pectin backbone as the wild-type, except for the calcium-bound pectin fraction exhibiting relatively less rhamnogalacturonan I. Next to pectin modification, xyloglucan populations from both transgenic lines were altered resulting in different XSGG and XXGG proportion in comparison to wild-type. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structure of a pectin methylesterase from Yersinia enterocolitica

PubMed Central

Boraston, Alisdair B.; Abbott, D. Wade

2012-01-01

Pectin methylesterases (PMEs) are family 8 carbohydrate esterases (CE8s) which remove the methyl group from methylesterified galacturonic acid (GalA) residues within pectin. Although the role of pectinases such as PMEs within dedicated phytopathogens has been well established, the significance of homologous enzymes found within the genomes of human enteropathogens remains to be determined. Presented here is the low-resolution (3.5 Å) structure of the CE8 from Yersinia enterocolitica (YeCE8). The high degree of structural conservation in the topology of the active-site cleft and catalytic apparatus that is shared with a characterized PME from a bacterial phytopathogen (i) indicates that YeCE8 is active on methylated pectin and (ii) highlights a more prominent role for pectin utilization in Yersinia than in other enteropathogenic species. PMID:22297983

Constitutive and inducible pectinolytic enzymes from Aspergillus flavipes FP-500 and their modulation by pH and carbon source

PubMed Central

Martínez-Trujillo, Aurora; Aranda, Juan S.; Gómez-Sánchez, Carlos; Trejo-Aguilar, Blanca; Aguilar-Osorio, Guillermo

2009-01-01

Growth and enzymes production by Aspergillus flavipes FP-500 were evaluated on pectin, polygalacturonic acid, galacturonic acid, arabinose, rhamnose, xylose, glycerol and glucose at different initial pH values. We found that the strain produced exopectinases, endopectinases and pectin lyases. Exopectinases and pectin lyase were found to be produced at basal levels as constitutive enzymes and their production was modulated by the available carbon source and pH of culture medium and stimulated by the presence of inducer in the culture medium. Endo-pectinase was basically inducible and was only produced when pectin was used as carbon source. Our results suggest that pectinases in A. flavipes FP-500 are produced in a concerted way. The first enzyme to be produced was exopectinase followed by Pectin Lyase and Endo-pectinase. PMID:24031315

Developmental Localization and Methylesterification of Pectin Epitopes during Somatic Embryogenesis of Banana (Musa spp. AAA)

PubMed Central

Xu, Chunxiang; Zhao, Lu; Pan, Xiao; Šamaj, Jozef

2011-01-01

Background The plant cell walls play an important role in somatic embryogenesis and plant development. Pectins are major chemical components of primary cell walls while homogalacturonan (HG) is the most abundant pectin polysaccharide. Developmental regulation of HG methyl-esterification degree is important for cell adhesion, division and expansion, and in general for proper organ and plant development. Methodology/Principal Findings Developmental localization of pectic homogalacturonan (HG) epitopes and the (1→4)-β-D-galactan epitope of rhamnogalacturonan I (RG-I) and degree of pectin methyl-esterification (DM) were studied during somatic embryogenesis of banana (Musa spp. AAA). Histological analysis documented all major developmental stages including embryogenic cells (ECs), pre-globular, globular, pear-shaped and cotyledonary somatic embryos. Histochemical staining of extracellularly secreted pectins with ruthenium red showed the most intense staining at the surface of pre-globular, globular and pear-shaped somatic embryos. Biochemical analysis revealed developmental regulation of galacturonic acid content and DM in diverse embryogenic stages. Immunodots and immunolabeling on tissue sections revealed developmental regulation of highly methyl-esterified HG epitopes recognized by JIM7 and LM20 antibodies during somatic embryogenesis. Cell walls of pre-globular/globular and late-stage embryos contained both low methyl-esterified HG epitopes as well as partially and highly methyl-esterified ones. Extracellular matrix which covered surface of early developing embryos contained pectin epitopes recognized by 2F4, LM18, JIM5, JIM7 and LM5 antibodies. De-esterification of cell wall pectins by NaOH caused a decrease or an elimination of immunolabeling in the case of highly methyl-esterified HG epitopes. However, immunolabeling of some low methyl-esterified epitopes appeared stronger after this base treatment. Conclusions/Significance These data suggest that both low- and highly-methyl-esterified HG epitopes are developmentally regulated in diverse embryogenic stages during somatic embryogenesis. This study provides new information about pectin composition, HG methyl-esterification and developmental localization of pectin epitopes during somatic embryogenesis of banana. PMID:21826225

Insights into the effects of polygalacturonase FaPG1 gene silencing on pectin matrix disassembly, enhanced tissue integrity, and firmness in ripe strawberry fruits

PubMed Central

Posé, Sara; Paniagua, Candelas; Cifuentes, Manuel; Blanco-Portales, Rosario; Quesada, Miguel A.; Mercado, José A.

2013-01-01

Antisense-mediated down-regulation of the fruit-specific polygalacturonase (PG) gene FaPG1 in strawberries (Fragaria×ananassa Duch.) has been previously demonstrated to reduce fruit softening and to extend post-harvest shelf life, despite the low PG activity detected in this fruit. The improved fruit traits were suggested to be attributable to a reduced cell wall disassembly due to FaPG1 silencing. This research provides empirical evidence that supports this assumption at the biochemical, cellular, and tissue levels. Cell wall modifications of two independent transgenic antisense lines that demonstrated a >90% reduction in FaPG1 transcript levels were analysed. Sequential extraction of cell wall fractions from control and ripe fruits exhibited a 42% decrease in pectin solubilization in transgenic fruits. A detailed chromatographic analysis of the gel filtration pectin profiles of the different cell wall fractions revealed a diminished depolymerization of the more tightly bound pectins in transgenic fruits, which were solubilized with both a chelating agent and sodium carbonate. The cell wall extracts from antisense FaPG1 fruits also displayed less severe in vitro swelling. A histological analysis revealed more extended cell–cell adhesion areas and an enhanced tissue integrity in transgenic ripe fruits. An immunohistological analysis of fruit sections using the JIM5 antibody against low methyl-esterified pectins demonstrated a higher labelling in transgenic fruit sections, whereas minor differences were observed with JIM7, an antibody that recognizes highly methyl-esterified pectins. These results support that the increased firmness of transgenic antisense FaPG1 strawberry fruits is predominantly due to a decrease in pectin solubilization and depolymerization that correlates with more tightly attached cell wall-bound pectins. This limited disassembly in the transgenic lines indicates that these pectin fractions could play a key role in tissue integrity maintenance that results in firmer ripe fruit. PMID:23873994

Engineering Chimeric Receptors To Investigate the Size- and Rigidity-Dependent Interaction of PEGylated Nanoparticles with Cells.

PubMed

Huang, Wei-Chiao; Burnouf, Pierre-Alain; Su, Yu-Cheng; Chen, Bing-Mae; Chuang, Kuo-Hsiang; Lee, Chia-Wei; Wei, Pei-Kuen; Cheng, Tian-Lu; Roffler, Steve R

2016-01-26

Attachment of ligands to the surface of nanoparticles (NPs) is an attractive approach to target specific cells and increase intracellular delivery of nanocargos. To expedite investigation of targeted NPs, we engineered human cancer cells to express chimeric receptors that bind polyethylene glycol (PEG) and internalize stealth NPs in a fashion similar to ligand-targeted liposomes against epidermal growth factor receptor 1 or 2 (HER1 or HER2), which are validated targets for cancer therapy. Measurement of the rate of endocytosis and lysosomal accumulation of small (80-94 nm) or large (180-220 nm) flexible liposomes or more rigid lipid-coated mesoporous silica particles in human HT29 colon cancer and SKBR3 breast cancer cells that express chimeric receptors revealed that larger and more rigid NPs were internalized more slowly than smaller and more flexible NPs. An exception is when both the small and large liposomes underwent endocytosis via HER2. HER1 mediated faster and greater uptake of NPs into cells but retained NPs less well as compared to HER2. Lysosomal accumulation of NPs internalized via HER1 was unaffected by NP rigidity but was inversely related to NP size, whereas large rigid NPs internalized by HER2 displayed increased lysosomal accumulation. Our results provide insight into the effects of NP properties on receptor-mediated endocytosis and suggest that anti-PEG chimeric receptors may help accelerate investigation of targeted stealth NPs.

Yield and quality of pectins extractable from the peels of thai mango cultivars depending on fruit ripeness.

PubMed

Sirisakulwat, Suparat; Nagel, Andreas; Sruamsiri, Pittaya; Carle, Reinhold; Neidhart, Sybille

2008-11-26

Pectins, recovered from the peels of four mango ( Mangifera indica L.) cultivars by mimicking industrial techniques, were evaluated in terms of yield, composition, macromolecular properties, and technofunctional quality. Freeze-dried peels of mature-green fruits, after major mesocarp softening, and at full ripeness were extracted using hot acid. The pectins were precipitated in propan-2-ol and their crude yields quantified as alcohol-insoluble substance. Like apple pomace, the dried peels provided hardly acetylated (DAc < 6.3%) rapid-set to ultrarapid-set high-methoxyl pectins at starch-adjusted yields of 11-21 g/100 g. However, despite similar high molecular weight fractions and galacturonic acid/rhamnose ratios, their average molecular weight was markedly reduced by a characteristic, almost monodisperse fraction of 16000-19000. Expanded galactans, indicated by galactose/rhamnose ratios of 15-24 mol/mol, probably represented arabinogalactan side-chain fragments withstanding hot-acid extraction at pH 1.5 and 2.0, as implied by arabinose/galactose ratios of 8-15 and 33-56 mol/100 mol, respectively. Limited galacturonic acid contents made the mango peel pectins less valuable than commercial apple pectins with regard to gelling capacity and thickening properties. Whereas starch and matrix glycan fragments almost completely degraded during ripening, depolymerization of pectins and galactans was insignificant. Technofunctional properties, modulated by extraction at different pH values, were ascribed to structural differences influencing macromolecular entanglements.

The structure of high-methoxyl sugar acid gels of citrus pectin as determined by AFM

USDA-ARS?s Scientific Manuscript database

Images of native high methoxyl sugar acid gels (HMSAG) were obtained by atomic force microscopy (AFM) in the Tapping ModeTM. Electronic thinning of the pectin strands to one pixel wide allowed the pectin network to be viewed in the absence of variable strand widths related to preferentially solvate...

Direct compression of chitosan: process and formulation factors to improve powder flow and tablet performance.

PubMed

Buys, Gerhard M; du Plessis, Lissinda H; Marais, Andries F; Kotze, Awie F; Hamman, Josias H

2013-06-01

Chitosan is a polymer derived from chitin that is widely available at relatively low cost, but due to compression challenges it has limited application for the production of direct compression tablets. The aim of this study was to use certain process and formulation variables to improve manufacturing of tablets containing chitosan as bulking agent. Chitosan particle size and flow properties were determined, which included bulk density, tapped density, compressibility and moisture uptake. The effect of process variables (i.e. compression force, punch depth, percentage compaction in a novel double fill compression process) and formulation variables (i.e. type of glidant, citric acid, pectin, coating with Eudragit S®) on chitosan tablet performance (i.e. mass variation, tensile strength, dissolution) was investigated. Moisture content of the chitosan powder, particle size and the inclusion of glidants had a pronounced effect on its flow ability. Varying the percentage compaction during the first cycle of a double fill compression process produced chitosan tablets with more acceptable tensile strength and dissolution rate properties. The inclusion of citric acid and pectin into the formulation significantly decreased the dissolution rate of isoniazid from the tablets due to gel formation. Direct compression of chitosan powder into tablets can be significantly improved by the investigated process and formulation variables as well as applying a double fill compression process.

Phosphatidylcholine nanovesicles coated with chitosan or chondroitin sulfate as novel devices for bacteriocin delivery

NASA Astrophysics Data System (ADS)

da Silva, Indjara Mallmann; Boelter, Juliana Ferreira; da Silveira, Nádya Pesce; Brandelli, Adriano

2014-07-01

There is increased interest on the use of natural antimicrobial peptides in biomedicine and food preservation technologies. In this study, the antimicrobial activity of nisin encapsulated into nanovesicles containing polyanionic polysaccharides was investigated. Nisin was encapsulated in phosphatidylcholine (PC) liposomes containing chitosan or chondroitin sulfate by the thin-film hydration method and tested for antimicrobial activity against Listeria spp. The mean particle size of PC liposomes was 145 nm and varied to 210 and 134 nm with the incorporation of chitosan and chondroitin sulfate, respectively. Nisin-containing nanovesicles with and without incorporation of polysaccharides had a zeta potential values around -20 mV, showing mostly spherical structures when observed by transmission electron microscopy. Encapsulated nisin had similar efficiency as free nisin in inhibiting Listeria spp. isolated from bovine carcass, and greater efficiency in inhibiting Listeria monocytogenes. The formulation containing chitosan was more stable and more efficient in inhibiting L. monocytogenes when compared to the other nanovesicles tested. After 24 h, the viable cell counts were 2 log lower as compared with the other treatments and 7 log comparing to controls.

DNA cytoskeleton for stabilizing artificial cells.

PubMed

Kurokawa, Chikako; Fujiwara, Kei; Morita, Masamune; Kawamata, Ibuki; Kawagishi, Yui; Sakai, Atsushi; Murayama, Yoshihiro; Nomura, Shin-Ichiro M; Murata, Satoshi; Takinoue, Masahiro; Yanagisawa, Miho

2017-07-11

Cell-sized liposomes and droplets coated with lipid layers have been used as platforms for understanding live cells, constructing artificial cells, and implementing functional biomedical tools such as biosensing platforms and drug delivery systems. However, these systems are very fragile, which results from the absence of cytoskeletons in these systems. Here, we construct an artificial cytoskeleton using DNA nanostructures. The designed DNA oligomers form a Y-shaped nanostructure and connect to each other with their complementary sticky ends to form networks. To undercoat lipid membranes with this DNA network, we used cationic lipids that attract negatively charged DNA. By encapsulating the DNA into the droplets, we successfully created a DNA shell underneath the membrane. The DNA shells increased interfacial tension, elastic modulus, and shear modulus of the droplet surface, consequently stabilizing the lipid droplets. Such drastic changes in stability were detected only when the DNA shell was in the gel phase. Furthermore, we demonstrate that liposomes with the DNA gel shell are substantially tolerant against outer osmotic shock. These results clearly show the DNA gel shell is a stabilizer of the lipid membrane akin to the cytoskeleton in live cells.

In vivo distribution and antitumor activity of heparin-stabilized doxorubicin-loaded liposomes.

PubMed

Han, Hee Dong; Lee, Aeri; Song, Chung Kil; Hwang, Taewon; Seong, Hasoo; Lee, Chong Ock; Shin, Byung Cheol

2006-04-26

The purpose of this study was to investigate the effect of heparin conjugation to the surface of doxorubicin (DOX)-loaded liposomes on the circulation time, biodistribution and antitumor activity after intravenous injection in murine B16F10 melanoma tumor-bearing mice. The heparin-conjugated liposomes (heparin-liposomes) were prepared by fixation of the negatively charged heparin to the positively charged liposomes. The existence of heparin on the liposomal surface was confirmed by measuring the changes in the particle size, zeta potential and heparin amount of the liposomes. The stability of the heparin-liposomes in serum was higher than that of the control liposomes, due to the heparin-liposomes being better protected from the adsorption of serum proteins. The DOX-loaded heparin-liposomes showed high drug levels for up to 64 h after the intravenous injection and the half-life of DOX was approximately 8.4- or 1.5-fold higher than that of the control liposomes or polyethyleneglycol-fixed liposomes (PEG-liposomes), respectively. The heparin-liposomes accumulated to a greater extent in the tumor than the control or PEG-liposomes as a result of their lower uptake by the reticuloendothelial system cells in the liver and spleen. In addition, the DOX-loaded heparin-liposomes retarded the growth of the tumor effectively compared with the control or PEG-liposomes. These results indicate the promising potential of heparin-liposomes as a new sterically stabilized liposomal delivery system for the enhancement of the therapeutic efficacy of chemotherapeutic agents.

New method for a two-step hydrolysis and chromatographic analysis of pectin neutral sugar chains.

PubMed

Garna, Haikel; Mabon, Nicolas; Wathelet, Bernard; Paquot, Michel

2004-07-28

A new method for the determination of the main neutral sugars in pectin has been developed. The sample preparation involves a mild chemical attack followed by an enzymatic hydrolysis. The completeness and nondestructive character of the method are demonstrated by comparison of the results obtained with different acids such as H2SO4, HCl, and trifluoroacetic acid (TFA) at different concentrations (2, 1, or 0.2 M) at two temperatures (80 or 100 degrees C). The chemical hydrolysis of pectin neutral sugar chains with strong acid (1 or 2 M) and high temperature (100 degrees C) shows that the liberation of the pectin sugars is not realized at the same rate for each sugar. Different optimum conditions are thus obtained. However, the chemical pectin hydrolysis with 0.2 M TFA at 80 degrees C is characterized by the liberation of pectin neutral sugar side chains without any degradation within 72 h of hydrolysis. Under these conditions, the liberation of some pectin sugars, essentially galactose, glucose, and rhamnose, was not complete. An enzymatic hydrolysis is necessary to obtain a complete release of all the sugars. The combination of the two treatments, a chemical hydrolysis realized with diluted acid (0.2 M) for 72 h at low temperature (80 degrees C) on one hand and an enzymatic hydrolysis on the other hand, allow a total liberation of pectin sugars. The quantitative analysis of the carbohydrates is realized with accuracy, high selectivity, and sensitivity with high-performance anion-exchange chromatography with pulsed-amperometric detection. The sugars can be analyzed without any derivatization with a limit of quantification of 0.1 mM. Copyright 2004 American Chemical Society

Influence of Structure, Charge, and Concentration on the Pectin-Calcium-Surfactant Complexes.

PubMed

Joshi, Nidhi; Rawat, Kamla; Bohidar, H B

2016-05-12

Polymer-surfactant complex formation of pectin with different types of surfactants, cationic (cetyltrimethylammonium bromide, CTAB and dodecyl trimethylammonium bromide, DTAB), anionic (sodium dodecyl sulfate, SDS), and neutral (Triton X-100, TX-100), was investigated at room temperature in the presence and absence of cross-linker calcium chloride using light scattering, zeta potential, rheology, and UV-vis spectroscopic measurements where the surfactant concentration was maintained below their critical micellar concentration (CMC). Results indicated that the interaction of cationic surfactant with pectin in the presence and absence of calcium chloride was much stronger compared to anionic and neutral surfactants. The neutral surfactant showed identifiable interaction despite the absence of any charged headgroup, while anionic surfactant showed feeble or very weak interaction with the polymer. The pectin-CTAB or DTAB complex formation was attributed to associative electrostatic and hydrophobic interactions. On comparison between the cationic surfactants, it was found that CTAB interacts strongly with pectin because of its long hydrocarbon chain. The morphology of complexes formed exhibited random coil structures while at higher concentration of surfactant, rod-like or extended random coil structures were noticed. Thus, functional characteristics of the complex could be tuned by varying the type of surfactant (charge and structure) and its concentration. The differential network rigidity (pectin-CTAB versus pectin-DTAB gels) obtained from rheology measurements showed that addition of a very small amount of surfactant (concentration ≪ CMC) was required for enhancing network strength, while the presence of a large amount of surfactant resulted in the formation of fragile gels. No gel formation occurred when the surfactant concentration was close to their CMC values. Considering the importance of pectin in food and pharmaceutical industry, this study is relevant.

Effect of extraction condition on properties of pectin from banana peels and its function as fat replacer in salad cream.

PubMed

Maneerat, Nitjaree; Tangsuphoom, Nattapol; Nitithamyong, Anadi

2017-02-01

Banana peels are wasted from banana processing industry. Pectin is a soluble dietary fibre usually prepared from fruit and vegetable processing wastes. Pectin extraction from banana peels thus should be an effective way of waste utilization. This study aimed to determine the effect of extraction condition on the properties of pectin from peels of Nam Wa banana ( Musa (ABB group) 'Kluai Nam Wa') and its role as fat replacer in salad cream. Banana peel pectin (BPP) was extracted with HCl (pH 1.5) and water (pH 6.0) for 30-120 min at 90 ± 5 °C. Acid extraction yielded 7-11% pectin on a dry basis with galacturonic acid content (GalA), degree of methylation (DM), and viscosity-average molecular weight (M v ) of 42-47, 57-61%, and 17-40 kDa, respectively; while water-extracted BPP contained lower DM but higher GalA and M v . Prolonged extraction raised the pectin yield but lowered the M v of BPP and the viscosity of their solutions. Incorporation of BPP obtained from 60 min acid- and water-extraction into salad cream at 30% oil substitution level resulted in the decreases in viscosity and lightness. All reduced-fat samples were stable to cream separation during 3-weeks storage although the formula containing water-extracted BPP had larger oil droplet size and greater extent of droplet flocculation. There was no difference in sensory scores rated by 50 panelists on thickness, smoothness, and overall acceptability of the full- and reduced-fat salad creams. Therefore, Nam Wa banana peels can be an alternative source of pectin with potential application as fat replacer in food products.

Cellulose-Pectin Spatial Contacts Are Inherent to Never-Dried Arabidopsis Primary Cell Walls: Evidence from Solid-State Nuclear Magnetic Resonance1[OPEN

PubMed Central

Wang, Tuo; Park, Yong Bum; Hong, Mei

2015-01-01

The structural role of pectins in plant primary cell walls is not yet well understood because of the complex and disordered nature of the cell wall polymers. We recently introduced multidimensional solid-state nuclear magnetic resonance spectroscopy to characterize the spatial proximities of wall polysaccharides. The data showed extensive cross peaks between pectins and cellulose in the primary wall of Arabidopsis (Arabidopsis thaliana), indicating subnanometer contacts between the two polysaccharides. This result was unexpected because stable pectin-cellulose interactions are not predicted by in vitro binding assays and prevailing cell wall models. To investigate whether the spatial contacts that give rise to the cross peaks are artifacts of sample preparation, we now compare never-dried Arabidopsis primary walls with dehydrated and rehydrated samples. One-dimensional 13C spectra, two-dimensional 13C-13C correlation spectra, water-polysaccharide correlation spectra, and dynamics data all indicate that the structure, mobility, and intermolecular contacts of the polysaccharides are indistinguishable between never-dried and rehydrated walls. Moreover, a partially depectinated cell wall in which 40% of homogalacturonan is extracted retains cellulose-pectin cross peaks, indicating that the cellulose-pectin contacts are not due to molecular crowding. The cross peaks are observed both at −20°C and at ambient temperature, thus ruling out freezing as a cause of spatial contacts. These results indicate that rhamnogalacturonan I and a portion of homogalacturonan have significant interactions with cellulose microfibrils in the native primary wall. This pectin-cellulose association may be formed during wall biosynthesis and may involve pectin entrapment in or between cellulose microfibrils, which cannot be mimicked by in vitro binding assays. PMID:26036615

We be jammin’: an update on pectin biosynthesis, trafficking and dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Charles T.

2015-11-20

Pectins are complex polysaccharides that contain acidic sugars and are major determinants of the cohesion, adhesion, extensibility, porosity and electrostatic potential of plant cell walls. Recent evidence has solidified their positions as key regulators of cellular growth and tissue morphogenesis, although important details of how they achieve this regulation are still missing. Pectins are also hypothesized to function as ligands for wall integrity sensors that enable plant cells to respond to intrinsic defects in wall biomechanics and to wall degradation by attacking pathogens. This update highlights recent advances in our understanding of the biosynthesis of pectins, how they are deliveredmore » to the cell surface and become incorporated into the cell wall matrix and how pectins are modified over time in the apoplast. It also poses unanswered questions for further research into this enigmatic but essential class of carbohydrate polymers.« less

Controlled release of sulfasalazine release from "smart" pectin gel microspheres under physiological simulated fluids.

PubMed

Costas, Luciana; Pera, Licia M; López, Azucena Gómez; Mechetti, Magdalena; Castro, Guillermo R

2012-07-01

Sulfasalazine (SLZ) is a synthetic nonsteroidal anti-inflammatory drug used mainly for the treatment of an inflammatory bowel and other diseases. Two pectins with different methylation degrees were blended to synthesized gel microspheres by ionotropic gelation for SLZ encapsulation. The encapsulation efficiency was found to be around of 99% in all formulations tested. However, different SLZ release profiles related to the methylation degrees of pectin were observed. Mixture of low methylated (LM) and high methylated (HM) pectins in the presence of calcium(II) displayed the best microsphere morphologies among the formulations tested determined by optical and electronic microscopies. The percentage of drug release using a mixture of LM and HM pectins after 255 min in simulated gastric fluid (pH = 1.2), simulated intestinal fluid (pH = 6.8), and phosphate buffer (pH = 7.4) were 15.0%, 47.0%, and 52.2%, respectively.

Pectin assisted one-pot synthesis of three dimensional porous NiO/graphene composite for enhanced bioelectrocatalysis in microbial fuel cells

NASA Astrophysics Data System (ADS)

Wu, Xiaoshuai; Shi, Zhuanzhuan; Zou, Long; Li, Chang Ming; Qiao, Yan

2018-02-01

A three dimensional (3D) porous nickel oxide (NiO)/graphene composite is developed through one-pot hydrothermal synthesis with a biopolymer-pectin for tailoring the porous structure. The introduction of pectin makes the NiO grow into nanoflakes-assembled micro spheres that insert in the graphene layers rather than just deposit on the surface of graphene nanosheets as nanoparticles. As the increase of pectin ratio, the size and the amount of NiO micro spheres are both increased, which resulting a 3D hierarchical porous structure. With the optimized pectin concentration, the obtained NiO/graphene nanocomposite anode possesses good electrocatalytic capability and delivers maximum power density of 3.632 Wm-2 in Shewanella putrefaciens CN32 microbial fuel cells (MFCs). This work provides a new way to develop low cost, high performance anode materials for MFCs.

Effects of temperature, ultraviolet radiation and pectin methyl esterase on aerobic methane release from plant material.

PubMed

Bruhn, D; Mikkelsen, T N; Obro, J; Willats, W G T; Ambus, P

2009-11-01

This study examines the effects of different irradiance types on aerobic methane (CH(4)) efflux rates from terrestrial plant material. Furthermore, the role of the enzyme pectin methyl esterase (PME) on CH(4) efflux potential was also examined. Different types of plant tissue and purified pectin were incubated in glass vials with different combinations of irradiation and/or temperature. Purified dry pectin was incubated in solution, and with or without PME. Before and after incubation, the concentration of CH(4) was measured with a gas chromatograph. Rates of CH(4) emission were found to depend exponentially on temperature and linearly on UV-B irradiance. UV-B had a greater stimulating effect than UV-A, while visible light had no effect on emission rates. PME was found to substantially reduce the potential for aerobic CH(4) emissions upon demethylation of pectin.

From waste to high-value product: Jackfruit peel derived pectin/apatite bionanocomposites for bone healing applications.

PubMed

Govindaraj, Dharman; Rajan, Mariappan; Hatamleh, Ashraf A; Munusamy, Murugan A

2018-01-01

Public requirements encouraged by the current asset framework drive industry to expand its general effectiveness by enhancing existing procedures or finding new uses for waste. Thus, the aim of this study was the isolation, fabrication, and characterization of pectin derived from jackfruit (Artocarpus heterophyllus) peels and the generation of hybrid of pectin (P)/apatite (HA) (P/HA) bionanocomposites. In this process, the natural pectin polymer derived from the peel of jackfruits was used in different concentrations for the fabrication of HA bionanocomposites. Characterization of the isolated pectin and bionanocomposites samples was performed with 1 H NMR and 13 C NMR, FTIR, XRD, SEM-EDX, and HR-TEM. Cytocompatibility, ALP, fibroblast stem cells, anti-inflammatory and cell adhesion testing of the fabricated bionanocomposites was showed good biocompatibility. Our results signify that the fabricated bionanocomposites might be applicable as bone graft materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Polyelectrolyte Multicomponent Colloidosomes Loaded with Nisin Z for Enhanced Antimicrobial Activity against Foodborne Resistant Pathogens

PubMed Central

Niaz, Taskeen; Shabbir, Saima; Noor, Tayyaba; Abbasi, Rashda; Raza, Zulfiqar A.; Imran, Muhammad

2018-01-01

Food grade micro- or nano-carrier systems (NCS) are being developed to improve the controlled release of antimicrobial agents. To augment the stability of liposomal NCS and to overcome the limitations associated with the use of free bacteriocin (nisin) in the food system, multi-component colloidosomes (MCCS) were developed by electrostatic interactions between anionic alginate and cationic chitosan (multilayer) around phospholipids based liposomes (core). Zeta-sizer results revealed the average diameter of 145 ± 2 nm, 596 ± 3 nm, and 643 ± 5 nm for nano-liposome (NL), chitosomes (chitosan coated NL) and MCCS, respectively. Zeta potential values of NCS varied from −4.37 ± 0.16 mV to 33.3 ± 6 mV, thus both chitosomes (CS) and MCCS were positively charged. Microstructure analysis by scanning electron microscope (SEM) revealed relatively higher size of MCCS with smooth and round morphology. TGA and DSC based experiments revealed that MCCS were thermally more stable than uncoated liposomes. Encapsulation efficiency of nisin in MCCS was observed to be 82.9 ± 4.1%, which was significantly higher than NL (56.5 ± 2.5%). FTIR analyses confirmed the cross-linking between sodium alginate and chitosan layer. Both qualitative (growth kinetics) and quantitative (colony forming unit) antimicrobial assays revealed that nisin loaded MCCS have superior potential to control resistant foodborne pathogens including Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis, (5.8, 5.4, and 6.1 Log CFUmL−1 reduction, respectively) as compared to free nisin, loaded NL or CS. Controlled release kinetics data fitted with Korsmeyer–Peppas model suggested that nisin release from MCCS followed Fickian diffusion. Cytotoxic studies on human blood cells and HepG2 cell lines revealed hemocompatibility and non-toxicity of MCCS. Thus, due to enhanced controlled release, stability and biocompatibility; these multi-component colloidosomes can be useful for incorporating antimicrobial agents into functional foods, beverages and pharmaceutical products to combat pathogenic and spoilage bacteria. PMID:29379490

Enzymatic modification of a model homogalacturonan with the thermally tolerant pectin methylesterase from citrus: I. Nanostructural characterization, enzyme mode of action and effect of pH

USDA-ARS?s Scientific Manuscript database

Methyl ester distribution in pectin homogalacturonan has a major influence on functionality. Enzymatic engineering of pectin nanostructure for tailoring functionality can expand pectin’s role as a food formulating agent and its in situ modification in prepared foods. We report on the mode of action ...

New, hybrid pectin-based biosorbents

PubMed Central

Jakóbik-Kolon, Agata; Milewski, Andrzej K.; Karoń, Krzysztof; Bok-Badura, Joanna

2016-01-01

ABSTRACT In this work hybrid pectin-based biosorbents with secondary polysaccharide additives (gellan, carob and xanthan gum, ratio to pectin 1:1, 1:1 and 1:3, respectively) were obtained at two temperatures. The presence of these additives in prepared beads was confirmed by Raman spectra. The SEM micrographs show better homogeneity of blends and grater differences between structures of beads with various additives obtained at higher temperature. The sorption capacity of our hybrid biosorbents as well as sole pectin sorbent is rather the same, and equals 0.85 and 0.70 mmol/g for lead and cadmium, respectively, in pH 4–6. PMID:27812233

Influence of Pectin as a green polymer electrolyte on the transport properties of Chitosan-Pectin membranes.

PubMed

Pasini Cabello, S D; Ochoa, N A; Takara, E A; Mollá, S; Compañ, V

2017-02-10

Novel blend membranes have been prepared from Chitosan (CH), Pectin (PEC) and their mixtures. The obtained samples were cross-linked and sulfonated before characterization. The results show that CH/PEC membranes display structural changes on the chemical and physical properties as a function of composition. DSC analysis reveals an endothermic peak due to the scission of the ionic pairs between carboxylic groups and ammonium groups, which produces a strong change on physical properties such as methanol permeability and proton conductivity. The methanol permeability decreases with the amount of Pectin from (4.24±0.04)×10 -6 cm 2 /s for pure Chitosan membrane to (1.51±0.03)×10 -6 cm 2 /s for blend CH/PEC membranes when the amount of Pectin is 50% (v/v). The proton conductivities of the blend membranes follow a similar behavior. For a pure CH membrane the conductivity is 2.44×10 -3 S/cm, decreasing with pectin content until the composition 50/50 (v/v), in which the conductivity drops almost one order of magnitude. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pectin-chitosan-PVA nanofibrous scaffold made by electrospinning and its potential use as a skin tissue scaffold.

PubMed

Lin, Hsin-Yi; Chen, Hsin-Hung; Chang, Shih-Hsin; Ni, Tsung-Sheng

2013-01-01

Scaffolds made of chitosan nanofibers are often too mechanically weak for their application and often their manufacturing processes involve the use of harmful and flammable organic solvents. In the attempt to improve the mechanical properties of nanofibrous scaffolds made of chitosan without the use of harmful chemicals, pectin, an anionic polymer was blended with chitosan, a cationic polymer, to form a polyelectrolyte complex and electrospun into nanofibers for the first time. The electrospun chitosan-pectin scaffolds, when compared to electrospun chitosan scaffolds, had a 58% larger diameter, a 21% higher Young's modulus, a 162% larger strain at break, and a 104% higher ultimate tensile strength. Compared to the chitosan scaffolds, the chitosan-pectin scaffolds' swelling ratios decreased by 55% after 60 min in a saline solution and more quickly released the preloaded tetracycline HCl. The L929 fibroblast cells proliferated slightly slower on the chitosan-pectin scaffolds than on the chitosan scaffolds. Nonetheless, cells on both materials deposited similar levels of extracellular type I collagen on a per DNA basis. In conclusion, a novel chitosan-pectin nanofibrous scaffold with superior mechanical properties than a chitosan nanofibrous scaffold was successfully made without the use of harmful solvents.

Properties of Two Novel Esterases Identified from Culture Supernatant of Penicillium purpurogenum Grown on Sugar Beet Pulp.

PubMed

Oleas, Gabriela; Callegari, Eduardo; Sepulveda, Romina; Eyzaguirre, Jaime

2016-01-01

The filamentous fungus Penicillium purpurogenum grows on a variety of natural carbon sources, such as sugar beet pulp, and secretes to the medium a large number of enzymes that degrade the carbohydrate components of lignocellulose. Sugar beet pulp is rich in pectin, and the purpose of this work is to identify novel esterases produced by the fungus, which may participate in pectin degradation. Partially purified culture supernatants of the fungus grown on sugar beet pulp were subjected to mass spectrometry analysis. Peptides thus identified, which may be part of potential esterases were probed against the proteins deduced from the fungal genome sequence. The cDNAs of two putative esterases identified were expressed in Pichia pastoris and their properties studied. One of these enzymes, named FAET, is a feruloyl esterase, while the other, PE, is classified as a pectin methyl esterase. These findings add to our knowledge of the enzymology of pectin degradation by Penicillium purpurogenum, and define properties of two novel esterases acting on de-esterification of pectin. Their availability may be useful as tools for the study of pectin structure and degradation.

Properties of Two Novel Esterases Identified from Culture Supernatant of Penicillium purpurogenum Grown on Sugar Beet Pulp

PubMed Central

Oleas, Gabriela; Callegari, Eduardo; Sepulveda, Romina; Eyzaguirre, Jaime

2017-01-01

Background The filamentous fungus Penicillium purpurogenum grows on a variety of natural carbon sources, such as sugar beet pulp, and secretes to the medium a large number of enzymes that degrade the carbohydrate components of lignocellulose. Sugar beet pulp is rich in pectin, and the purpose of this work is to identify novel esterases produced by the fungus, which may participate in pectin degradation. Methods and findings Partially purified culture supernatants of the fungus grown on sugar beet pulp were subjected to mass spectrometry analysis. Peptides thus identified, which may be part of potential esterases were probed against the proteins deduced from the fungal genome sequence. The cDNAs of two putative esterases identified were expressed in Pichia pastoris and their properties studied. One of these enzymes, named FAET, is a feruloyl esterase, while the other, PE, is classified as a pectin methyl esterase. Conclusions These findings add to our knowledge of the enzymology of pectin degradation by Penicillium purpurogenum, and define properties of two novel esterases acting on de-esterification of pectin. Their availability may be useful as tools for the study of pectin structure and degradation. PMID:28828411

Pectic oligosaccharides from agricultural by-products: production, characterization and health benefits.

PubMed

Babbar, Neha; Dejonghe, Winnie; Gatti, Monica; Sforza, Stefano; Elst, Kathy

2016-08-01

Pectin containing agricultural by-products are potential sources of a new class of prebiotics known as pectic oligosaccharides (POS). In general, pectin is made up of homogalacturonan (HG, α-1,4-linked galacturonic acid monomers) and rhamnogalacturonan (RG, alternate galacturonic acid and rhamnose backbone with neutral side chains). Controlled hydrolysis of pectin containing agricultural by-products like sugar beet, apple, olive and citrus by chemical, enzymatic and hydrothermal can be used to produce oligo-galacturonides (GalpOS), galacto-oligosaccharides (GalOS), rhamnogalacturonan-oligosaccharides (RGOS), etc. However, extensive research is needed to establish the role of POS, both as a prebiotic as well as therapeutic agent. This review comprehensively covers different facets of POS, including the nature and chemistry of pectin and POS, potential agricultural residual sources of pectin, pre-treatment methods for facilitating selective extraction of pectin, identification and characterization of POS, health benefits and important applications of POS in food and feed. This review has been compiled to establish a platform for future research in the purification and characterization of POS and for in vivo and in vitro studies of important POS, so that they could be commercially exploited.

Structural changes in cell wall pectins during strawberry fruit development.

PubMed

Paniagua, Candelas; Santiago-Doménech, Nieves; Kirby, Andrew R; Gunning, A Patrick; Morris, Victor J; Quesada, Miguel A; Matas, Antonio J; Mercado, José A

2017-09-01

Strawberry (Fragaria × anannasa Duch.) is one of the most important soft fruit. Rapid loss of firmness occurs during the ripening process, resulting in a short shelf life and high economic losses. To get insight into the role of pectin matrix in the softening process, cell walls from strawberry fruit at two developmental stages, unripe-green and ripe-red, were extracted and sequentially fractionated with different solvents to obtain fractions enriched in a specific component. The yield of cell wall material as well as the per fresh weight contents of the different fractions decreased in ripe fruit. The largest reduction was observed in the pectic fractions extracted with a chelating agent (trans-1,2- diaminocyclohexane-N,N,N'N'-tetraacetic acid, CDTA fraction) and those covalently bound to the wall (extracted with Na 2 CO 3 ). Uronic acid content of these two fractions also decreased significantly during ripening, but the amount of soluble pectins extracted with phenol:acetic acid:water (PAW) and water increased in ripe fruit. Fourier transform infrared spectroscopy of the different fractions showed that the degree of esterification decreased in CDTA pectins but increased in soluble fractions at ripen stage. The chromatographic analysis of pectin fractions by gel filtration revealed that CDTA, water and, mainly PAW polyuronides were depolymerised in ripe fruit. By contrast, the size of Na 2 CO 3 pectins was not modified. The nanostructural characteristics of CDTA and Na 2 CO 3 pectins were analysed by atomic force microscopy (AFM). Isolated pectic chains present in the CDTA fractions were significantly longer and more branched in samples from green fruit than those from red fruit. No differences in contour length were observed in Na 2 CO 3 strands between samples of both stages. However, the percentage of branched chains decreased from 19.7% in unripe samples to 3.4% in ripe fruit. The number of pectin aggregates was higher in green fruit samples of both fractions. These results show that the nanostructural complexity of pectins present in CDTA and Na 2 CO 3 fractions diminishes during fruit development, and this correlates with the solubilisation of pectins and the softening of the fruit. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Selectively Structural Determination of Cellulose and Hemicellulose in Plant Cell Wall

NASA Astrophysics Data System (ADS)

Huang, Shih-Chun; Park, Yong; Cosgrove, Daniel; Maranas, Janna; Janna Maranas Team; Daniel Cosgrove Team

2013-03-01

Primary plant cell walls support the plant body, and regulate cell size, and plant growth. It contains several biopolymers that can be categorized into three groups: cellulose, hemicellulose and pectin. To determine the structure of plant cell wall, we use small angle neutron scattering in combination with selective deuteration and contrast matching method. We compare the structure between wild Arabidopsis thaliana and its xyloglucan-deficient mutant. Hemicellulose in both samples forms coil with similar radii of gyration, and weak scattering from the mutant suggests a limited amount of hemicellulose in the xyloglucan-deficient mutant. We observe good amount of hemicellulose coating on cellulose microfibrils only in wild Arabidopsis. The absence of coating in its xyloglucan-deficient mutation suggests the other polysaccharides do not have comparable interaction with cellulose. This highlights the importance of xyloglucan in plant cell wall. At larger scale, the average distance between cellulose fibril is found smaller than reported value, which directly reflects on their smaller matured plant size. U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Center for LignoCellulose Structure and Formation

Improvement of pharmacokinetic and antitumor activity of layered double hydroxide nanoparticles by coating with PEGylated phospholipid membrane

PubMed Central

Yan, Mina; Zhang, Zhaoguo; Cui, Shengmiao; Lei, Ming; Zeng, Ke; Liao, Yunhui; Chu, Weijing; Deng, Yihui; Zhao, Chunshun

2014-01-01

Layered double hydroxide (LDH) has attracted considerable attention as a drug carrier. However, because of its poor in vivo behavior, polyethylene glycolylated (PEGylated) phospholipid must be used as a coformer to produce self-assembled core–shell nanoparticles. In the present study, we prepared a PEGylated phospholipid-coated LDH (PLDH) (PEG-PLDH) delivery system. The PEG-PLDH nanoparticles had an average size of 133.2 nm. Their core–shell structure was confirmed by transmission electron microscopy and X-ray photoelectron spectroscopy. In vitro liposome-cell-association and cytotoxicity experiments demonstrated its ability to be internalized by cells. In vivo studies showed that PEGylated phospholipid membranes greatly reduced the blood clearance rate of LDH nanoparticles. PEG-PLDH nanoparticles demonstrated a good control of tumor growth and increased the survival rate of mice. These results suggest that PEG-PLDH nanoparticles can be a useful drug delivery system for cancer therapy. PMID:25364245

Functional Anchoring Lipids for Drug Delivery Carrier Fabrication and Cell Surface Re-Engineering Applications

NASA Astrophysics Data System (ADS)

Vabbilisetty, Pratima

For decades, lipid vesicular bodies such as liposomes have been widely used and explored as biomimetic models of cell membranes and as drug/gene delivery carrier systems. Similarly, micellar iron oxide nanoparticles have also been investigated as potential MRI agents as well as drug delivery carrier systems. Cell surface carbohydrate-protein interactions allow them to serve as markers for recognition of many molecular and cellular activities thereby, are exploited as attractive molecules for surface modification of nanocarrier systems with purpose for tissues specific targeting and biocompatibility. In addition, the cell lipid membrane serves as an important platform for occurrence of many biological processes that are governed and guided by cell surface receptors. Introduction of chemoselective functional groups, via bio-orthogonal conjugation strategies, at the cell surface facilitates many cellular modifications and paves path for novel and potential biomedical applications. Anchoring lipids are needed for liposome surface functionalization with ligands of interest and play important roles in ligand grafting density, liposomes stability and biological activity. On the other hand, anchoring lipids are also needed for cell surface re-engineering by lipid fusion approach and have high impact for ligand insertion efficiency and biological activity. Overall, in this dissertation study, functional anchoring lipids for glyco-functionalized carrier systems and for efficient cell surface re-engineering applications were systematically investigated, respectively. Firstly, investigation of the synthesis of glyco-functionalized liposome systems based on phosphatidylethonalamine (PE) and cholesterol (Chol) anchoring lipids, prepared by post chemically selective functionalization via Staudinger ligation were carried out. The effect of anchor lipids on the stability, encapsulation and releasing capacity of the glycosylated liposomes were investigated by dynamic light scattering (DLS) technique and by entrapping 5, 6-carboxyfluorescein (CF) dye and monitoring the fluorescence leakage, respectively. Overall, the Chol-anchored liposomes showed faster releasing rate than DSPE-anchored liposomes. This could be due to the increase in rigidity of the lipid membrane upon inclusion of Chol, thereby, leading to fast leakage of liposomes. Second, the potential effects of phospholipid (PE) and cholesterol (Chol)-based anchor lipids on cell surface re-engineering via copper free click chemistry were assessed with RAW 264.7 cells as model. The confocal microscopy and flow cytometry results indicated the successful incorporation of biotinylated Chol-based anchor lipids after specific streptavidin-FITC binding onto the cell surface. Higher fluorescence intensities from the cell membrane were observed for Chol-based anchor lipids when compared to DSPE as anchoring lipid. Furthermore, cytotoxicity of the synthesized biotinylated anchor lipids on the RAW 264.7 cells was assessed by MTT assay. The MTT assay results further confirmed that cell surface re-engineering via lipid anchoring approach strategy has very little or negligible amount of cytotoxicity on the cell viability. Thus, this study suggests the possible use of these lipids for potential cell surface re-engineering applications. In addition, synthesis of lipid coated iron oxide nanoparticles via dual solvent exchange approach and their glyco-functionalization via Staudinger ligation were investigated and characterized by FT-IR and TEM techniques. The stability of iron oxide nanoparticles with varying compositions of lipid anchors was evaluated by dynamic light scattering technique.

Efficacy of pectin solution for preventing gastro-esophageal reflux events in patients with percutaneous endoscopic gastrostomy.

PubMed

Adachi, Kyoichi; Furuta, Kenji; Aimi, Masahito; Fukazawa, Kousuke; Shimura, Shino; Ohara, Shunji; Nakata, Shuji; Inoue, Yukiko; Ryuko, Kanji; Ishine, Junichi; Katoh, Kyoko; Hirata, Toshiaki; Ohhata, Shuzo; Katoh, Setsushi; Moriyama, Mika; Sumikawa, Masuko; Sanpei, Mari; Kinoshita, Yoshikazu

2012-05-01

The aim of this study was to determine the efficacy of pectin solution, which increases the viscosity of liquid nutrient, for prevention of gastro-esophageal reflux in comparison with half-solid nutrient. The subjects were 10 elderly patients undergoing percutaneous endoscopic gastrostomy feeding. Twenty-four-hour esophageal multichannel intraluminal impedance and pH testing was performed during intake of half-solid nutrient and a combination of pectin solution and liquid nutrient. During 4 h after delivery, there was no significant difference in the total number of gastro-esophageal reflux events between the feeding of the half-solid nutrient and the combination of pectin solution and liquid nutrient (5.7 ± 1.2 vs 5.3 ± 1.0/4 h). Acidic reflux after delivery of the half-solid nutrient was significantly more frequent than that after delivery of the combination of pectin solution and liquid nutrient (80.7% vs 60.4%, p = 0.018). The incidence of gastro-esophageal reflux reaching the upper portion of the esophagus tended to be higher during delivery of the half-solid nutrient than during delivery of the combination of pectin solution and liquid nutrient (47.4% vs 34.0%, p = 0.153). In conclusion, the usage of pectin solution combined with liquid nutrient is effective for preventing acidic gastro-esophageal reflux and gastro-esophageal reflux reaching the upper portion of the esophagus.

Structural and technological characterisation of pectin extracted with sodium citrate and nitric acid from sunflower heads.

PubMed

Muñoz-Almagro, Nerea; Rico-Rodriguez, Fabián; Wilde, Peter J; Montilla, Antonia; Villamiel, Mar

2018-05-18

An optimisation of temperature, time and extracting agent concentration of pectin extraction from sunflower heads using sodium citrate and nitric acid (SP-SC and SP-NA) was carried out. At optimal conditions, the yield of extraction with nitric acid (SPO-NA) was 2-fold greater than the corresponding with sodium citrate (SPO-SC) (14.3 vs 7.7%, respectively). Regarding pectin structure, the galacturonic acid (GalA) content in both, SPO-SC and SPO-NA, was similar (∼85%). However, SPO-NA showed lower molecular weight (Mw) (88.9 kDa) and neutral sugar content (4%) than SPO-SC (464 kDa, 9%), indicating that nitric acid deeply degraded pectin structure. These differences derived into dissimilar behaviour in their technological functionality. SPO-SC showed higher viscosity and better emulsifying capacity than SPO-NA, although any of them were able to stabilise the oil/water emulsion. Both sunflower pectins formed gels with Ca 2+ (75 mg/g of pectin) at pH 3.0. However, when sucrose was added, the gels formed by SP-SC and 20% sucrose presented the same hardness as those of SP-NA with 40% sucrose. These results suggest that the pectin extracted with sodium citrate, an eco-friendly agent, could be a promising ingredient, with good thickening and gelling properties. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Introduction and characterization of charged functional domains into an esterified pectic homogalacturonan by a citrus pectin methylesterase and comparison of its modes of action to other pectin methylesterase isozymes

USDA-ARS?s Scientific Manuscript database

One of the four pectin methylesterase isozymes isolated from Citrus sinensis variety Valencia fruit was used to demethylesterify a model homogalacturonan to 30%, 50% and 70% degree of methylesterification at pH 4.5 and 7.0, respectively. Introduced demethylesterified blocks were released by a limite...

pH-Sensitive Liposomes: Acid-Induced Liposome Fusion

NASA Astrophysics Data System (ADS)

Connor, Jerome; Yatvin, Milton B.; Huang, Leaf

1984-03-01

Sonicated unilamellar liposomes containing phosphatidylethanolamine and palmitoylhomocysteine fuse rapidly when the medium pH is lowered from 7 to 5. Liposome fusion was demonstrated by (i) mixing of the liposomal lipids as shown by resonance energy transfer, (ii) gel filtration, and (iii) electron microscopy. The pH-sensitive fusion of liposomes was observed only when palmitoylhomocysteine (>= 20 mol%) was present in the liposomes. The presence of phosphatidyl-ethanolamine in the liposomes greatly enhanced fusion whereas the presence of phosphatidylcholine inhibited fusion. During fusion of liposomes containing phosphatidylethanolamine and palmitoylhomocysteine (8:2, mol/mol), almost all of the encapsulated calcein was released. Inclusion of cholesterol (40 mol%) in the liposomes substantially decreased leakage without impairing fusion.

FT-IR and FT-Raman characterization of non-cellulosic polysaccharides fractions isolated from plant cell wall.

PubMed

Chylińska, Monika; Szymańska-Chargot, Monika; Zdunek, Artur

2016-12-10

The purpose of this work was to reveal the structural changes of cell wall polysaccharides' fractions during tomato fruit development by analysis of spectral data. Mature green and red ripe tomato fruit were taken into consideration. The FT-IR spectra of water soluble pectin (WSP), imidazole soluble pectin (ISP) and diluted alkali soluble pectin (DASP) contained bands typical for pectins. Whereas for KOH fraction spectra bands typical for hemicelluloses were present. The FT-IR spectra showed the drop down of esterification degree of WSP and ISP polysaccharides during maturation. The changes in polysaccharides structure revealed by spectra were the most visible in the case of pectic polysaccharides. The WSP and DASP fraction pectins molecules length were shortened during tomato maturation and ripening. Whereas the ISP fraction spectra analysis showed that this fraction contained rhamnogalacturonan I, but also for red ripe was rich in pectic galactan comparing with ISP fraction from mature green. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous influence of pectin and xyloglucan on structure and mechanical properties of bacterial cellulose composites.

PubMed

Szymańska-Chargot, Monika; Chylińska, Monika; Cybulska, Justyna; Kozioł, Arkadiusz; Pieczywek, Piotr M; Zdunek, Artur

2017-10-15

The impact of the matrix polysaccharides on the cellulose microfibrils structure as well as on the mechanical properties of cell walls still remains an open question. Therefore, the aim of investigations was to determine the simultaneous influence of (i) different concentrations of pectins with constant concentration of xyloglucan, and (ii) different concentrations of xyloglucan with constant concentration of pectins on cellulose structure. Composites of bacterial cellulose (BC) produced by Komagataeibacter xylinus are considered to mimic natural plant cell walls. This investigation showed that the lower the ratio of xyloglucan to pectin was, the higher Young's modulus of BC composite was and also obtained cellulose microfibrils were thinner. The increasing concentration of xyloglucan to pectin also caused the drop down in microfibrils crystallinity degree with predominant structure of cellulose I β . In that case, also the length of cellulose chains was growing and reaching the highest value among all BC composites. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biocompatible Polyelectrolyte Complex Nanoparticles from Lactoferrin and Pectin as Potential Vehicles for Antioxidative Curcumin.

PubMed

Yan, Jing-Kun; Qiu, Wen-Yi; Wang, Yao-Yao; Wu, Jian-Yong

2017-07-19

Polyelectrolyte complex nanoparticles (PEC NPs) were fabricated via electrostatic interactions between positively charged heat-denatured lactoferrin (LF) particles and negatively charged pectin. The obtained PEC NPs were then utilized as curcumin carriers. PEC NPs were prepared by mixing 1.0 mg/mL solutions of heat-denatured LF and pectin at a mass ratio of 1:1 (w/w) in the absence of NaCl at pH 4.50. PEC NPs that were prepared under optimized conditions were spherical in shape with a particle size of ∼208 nm and zeta potential of ∼-32 mV. Hydrophobic curcumin was successfully encapsulated into LF/pectin PEC NPs with high encapsulation efficiency (∼85.3%) and loading content (∼13.4%). The in vitro controlled release and prominent antioxidant activities of curcumin from LF/pectin PEC NPs were observed. The present work provides a facile and fast method to synthesize nanoscale food-grade delivery systems for the improved water solubility, controlled release, and antioxidant activity of hydrophobic curcumin.

FTIR studies of gluten matrix dehydration after fibre polysaccharide addition.

PubMed

Nawrocka, Agnieszka; Krekora, Magdalena; Niewiadomski, Zbigniew; Miś, Antoni

2018-06-30

FTIR spectroscopy was used to determine changes in secondary structure, as well as water state, in gluten and model doughs supplemented by four fibre polysaccharides (microcrystalline cellulose, inulin, apple pectin and citrus pectin). The gluten and model doughs were obtained from commercially available wheat gluten and model flour, respectively. The polysaccharides were used in five concentrations: 3%, 6%, 9%, 12% and 18%. Analysis of the FTIR spectra indicated that polysaccharides could be divided into two groups: first - microcrystalline cellulose and inulin, second - apple and citrus pectins that induced opposite structural changes. Changes in secondary structure concern mainly β-sheets and β-turns that form aggregated β-structures, suggesting dehydration of the gluten matrix as a result of competition for water between gluten proteins and polysaccharides. Moreover, the positive band at ca. 1226 cm -1 in the spectra of pectin-modified samples indicates formation of 'ether' type hydrogen bonds between gluten proteins and pectins. Copyright © 2018 Elsevier Ltd. All rights reserved.

Restricted cell elongation in Arabidopsis hypocotyls is associated with a reduced average pectin esterification level

PubMed Central

Derbyshire, Paul; McCann, Maureen C; Roberts, Keith

2007-01-01

Background Cell elongation is mainly limited by the extensibility of the cell wall. Dicotyledonous primary (growing) cell walls contain cellulose, xyloglucan, pectin and proteins, but little is known about how each polymer class contributes to the cell wall mechanical properties that control extensibility. Results We present evidence that the degree of pectin methyl-esterification (DE%) limits cell growth, and that a minimum level of about 60% DE is required for normal cell elongation in Arabidopsis hypocotyls. When the average DE% falls below this level, as in two gibberellic acid (GA) mutants ga1-3 and gai, and plants expressing pectin methyl-esterase (PME1) from Aspergillus aculeatus, then hypocotyl elongation is reduced. Conclusion Low average levels of pectin DE% are associated with reduced cell elongation, implicating PMEs, the enzymes that regulate DE%, in the cell elongation process and in responses to GA. At high average DE% other components of the cell wall limit GA-induced growth. PMID:17572910

Dissecting the polysaccharide-rich grape cell wall matrix using recombinant pectinases during winemaking.

PubMed

Gao, Yu; Fangel, Jonatan U; Willats, William G T; Vivier, Melané A; Moore, John P

2016-11-05

The effectiveness of enzyme-mediated-maceration in red winemaking relies on the use of an optimum combination of specific enzymes. A lack of information on the relevant enzyme activities and the corresponding polysaccharide-rich berry cell wall structure is a major limitation. This study used different combinations of purified recombinant pectinases with cell wall profiling tools to follow the deconstruction process during winemaking. Multivariate data analysis of the glycan microarray (CoMPP) and gas chromatography (GC) results revealed that pectin lyase performed almost as effectively in de-pectination as certain commercial enzyme mixtures. Surprisingly the combination of endo-polygalacturonase and pectin-methyl-esterase only unraveled the cell walls without de-pectination. Datasets from the various combinations used confirmed pectin-rich and xyloglucan-rich layers within the grape pomace. These data support a proposed grape cell wall model which can serve as a foundation to evaluate testable hypotheses in future studies aimed at developing tailor-made enzymes for winemaking scenarios. Copyright © 2016 Elsevier Ltd. All rights reserved.

Restricted cell elongation in Arabidopsis hypocotyls is associated with a reduced average pectin esterification level.

PubMed

Derbyshire, Paul; McCann, Maureen C; Roberts, Keith

2007-06-17

Cell elongation is mainly limited by the extensibility of the cell wall. Dicotyledonous primary (growing) cell walls contain cellulose, xyloglucan, pectin and proteins, but little is known about how each polymer class contributes to the cell wall mechanical properties that control extensibility. We present evidence that the degree of pectin methyl-esterification (DE%) limits cell growth, and that a minimum level of about 60% DE is required for normal cell elongation in Arabidopsis hypocotyls. When the average DE% falls below this level, as in two gibberellic acid (GA) mutants ga1-3 and gai, and plants expressing pectin methyl-esterase (PME1) from Aspergillus aculeatus, then hypocotyl elongation is reduced. Low average levels of pectin DE% are associated with reduced cell elongation, implicating PMEs, the enzymes that regulate DE%, in the cell elongation process and in responses to GA. At high average DE% other components of the cell wall limit GA-induced growth.

Using complexation for the microencapsulation of nisin in biopolymer matrices by spray-drying.

PubMed

Ben Amara, Chedia; Kim, Lanhee; Oulahal, Nadia; Degraeve, Pascal; Gharsallaoui, Adem

2017-12-01

The aim of this study is to investigate the potential of complexation to encapsulate nisin (5g/L concentration) using spray-drying technique and to evaluate how complexation with pectin or alginate (2g/L concentration) can preserve nisin structure and antimicrobial activity. Spray-drying of nisin-low methoxyl pectin or nisin-alginate electrostatic complexes has led to the microencapsulation of the peptide in different networks that were highly influenced by the polysaccharide type. Turbidity and particle size measurements indicated that while spray-drying promoted the aggregation of nisin-pectin complexes, it favored the dissociation of nisin-alginate aggregates to form individual complexes. Structural changes of nisin induced by complexation with pectin or alginate and spray-drying were studied by using UV-Vis absorption and fluorescence spectroscopy. The results showed that complexation with pectin or alginate preserved nisin structure as well as its antimicrobial activity during spray-drying. Copyright © 2017 Elsevier Ltd. All rights reserved.

Unavoidable food supply chain waste: acid-free pectin extraction from mango peel via subcritical water.

PubMed

Xia, H; Matharu, A S

2017-09-21

Mango peel is the major by-product of mango processing, and compromises 7-24% of the total mango weight. In this study, pectin was extracted from mango peel waste by using subcritical water extraction (SWE) in the absence of mineral acid. A highest yield of 18.34% was achieved from the Kesar variety and the pectin was characterised using ATR-IR spectroscopy, TGA and 13 C solid-state NMR spectroscopy to confirm the structure. The degree of esterification (DE) of the pectin was analysed with both titrimetry and 13 C solid-state NMR spectroscopy, and a high DE (>70%) was observed for all three varieties (Keitt, Sindhri and Kesar). This is the first report on acid-free subcritical water extraction of pectin from mango peel, which provides a green route for the valorisation of mango peel waste and contributes to a source of biobased materials and chemicals for a sustainable 21 st century.

Nutraceutically inspired pectin-Mg(OH)₂ nanocomposites for bioactive packaging applications.

PubMed

Moreira, Francys K V; De Camargo, Lais A; Marconcini, José M; Mattoso, Luiz H C

2013-07-24

This paper reports on the development of bioactive edible films based on pectin as a dietary matrix and magnesium hydroxide (Mg(OH)2) nanoplates as a reinforcing filler. Nanocomposites of high-methoxyl (HM) and low-methoxyl (LM) pectins were prepared using the casting method at concentrations of Mg(OH)2 ranging from 0.5 to 5 wt %. Atomic force microscopy and FTIR spectroscopy were employed to characterize the nanocomposite structure. The tensile properties and thermal stability of the nanocomposites were also examined to ascertain the effect of Mg(OH)2 inclusion and degree of methoxylation. The results provided evidence that the Mg(OH)2 nanoplates were uniformly dispersed and interacted strongly with the film matrix. The mechanical and thermal properties were significantly improved in the nanocomposite films compared to the control. Mg(OH)2 nanoplates were more effective in improving properties of LM pectin. Preliminary migration studies using arugula leaves confirmed that pectin-Mg(OH)2 nanocomposites can release magnesium hydroxide by contact, demonstrating their potential for magnesium supplementation in bioactive packaging.

Pre-Harvest Dropped Kinnow ( Citrus reticulata Blanco) Waste Management through the Extraction of Naringin and Pectin from their Peels using Indigenous Resin

NASA Astrophysics Data System (ADS)

Laxmi Deepak Bhatlu, M.; Katiyar, Prashant; Singh, Satya Vir; Verma, Ashok Kumar

2016-09-01

About 10-20 % kinnow fruits are dropped in preharvest stage which are waste and are problem to farmer as these create nuisance by rotting and insect rearing ground. The peels of these dropped fruits as well as peels from kinnow processing may be good source of naringin and pectin. Naringin is used in pharmaseutics while pectin is used in food industry. For recovery of naringin and pectn, peels of preharvest dropped kinnow fruits were boiled in water. The extract was passed through macroporus polymeric adsorbent resin Indion PA 800, naringin was adsorbed on it. The adsorbed naringin was desorbed with ethanol. This solution was passed through membrane filter and filtrate was evaporated to obtain naringin. The extract remaining after adsorption of naringin was used to recover pectin using acid extraction method. The recovery of naringin and pectin was about 52 and 58 % respectively. The naringin finally obtained had 91-93 % purity.

Hydrophobic edible films made up of tomato cutin and pectin.

PubMed

Manrich, Anny; Moreira, Francys K V; Otoni, Caio G; Lorevice, Marcos V; Martins, Maria A; Mattoso, Luiz H C

2017-05-15

Cutin is the biopolyester that protects the extracellular layer of terrestrial plants against dehydration and environmental stresses. In this work, cutin was extracted from tomato processing waste and cast into edible films having pectin as a binding agent. The influences of cutin/pectin ratio (50/50 and 25/75), film-forming suspension pH, and casting method on phase dispersion, water resistance and affinity, and thermal and mechanical properties of films were investigated. Dynamic light scattering and scanning electron microscopy revealed that cutin phase aggregation was reduced by simply increasing pH. The 50/50 films obtained by casting neutral-pH suspensions presented uniform cutin dispersion within the pectin matrix. Consequently, these films exhibited lower water uptake and solubility than their acidic counterparts. The cutin/pectin films developed here were shown to mimic tomato peel itself with respect to mechanical strength and thermal stability. Such behavior was found to be virtually independent of pH and casting method. Copyright © 2017 Elsevier Ltd. All rights reserved.

Blends of jackfruit seed starch-pectin in the development of mucoadhesive beads containing metformin HCl.

PubMed

Nayak, Amit Kumar; Pal, Dilipkumar

2013-11-01

In this work, calcium pectinate-jackfruit (Artocarpus heterophyllus Lam.) seed starch (JFSS) mucoadhesive beads containing metformin HCl were developed through ionotropic-gelation. Effects of pectin and JFSS amounts on drug encapsulation efficiency (DEE), and cumulative drug release after 10 h (R10 h) were optimized using 3(2) factorial design. The optimized calcium pectinate-JFSS beads containing metformin HCl showed DEE of 94.11 ± 3.92%, R10 h of 48.88 ± 2.02%, and mean diameter of 2.06 ± 0.20 mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The pH of test mediums was found critical for swelling and mucoadhesion of these beads. The optimized calcium pectinate-JFSS beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of soy hull pectin and insoluble fiber on physicochemical and oxidative characteristics of fresh and frozen/thawed beef patties.

PubMed

Kim, Hyun-Wook; Miller, Danika K; Lee, Yong Jae; Kim, Yuan H Brad

2016-07-01

The objective of this study was to determine the effects of pectin and insoluble fiber isolated from soy hulls on water-holding capacity (WHC), texture, color, and lipid oxidation of fresh and frozen/thawed beef patties. Beef patties were formulated with no dietary fiber (control), 1% soy hull pectin, insoluble fiber, or their mixture (1:1), respectively. The addition of soy hull pectin significantly decreased display weight loss and increased cook yield of both fresh and frozen/thawed beef patties. In addition, no significant difference in hardness between fresh and frozen/thawed beef patties was observed for all dietary fiber treatments. However, incorporation of insoluble soy hull fiber decreased color and lipid oxidation stabilities of both fresh and frozen/thawed beef patties. Our results indicate that the incorporation of soy hull pectin could be an effective non-meat ingredient to minimize water loss and hardness defects of frozen beef patties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Liposomes as carriers of macrolides: preferential association of erythromycin A and azithromycin with liposomes of phosphatidylglycerol containing unsaturated fatty acid(s).

PubMed

Stuhne-Sekalec, L; Stanacev, N Z; Djokic, S

1991-01-01

To assess the most favourable phospholipid composition of a liposomal carrier for antibiotics, small multilamellar liposomes were prepared from phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol of varying fatty acid composition in the presence of erythromycin A and azithromycin. Crude liposomes were subjected to Sepharose CL-4B column chromatography, and liposomes containing antibiotics were well separated from free antibiotics. These experiments established that the greatest association of antibiotics was achieved with liposomes prepared from phosphatidylglycerol rather than phosphatidylcholine or phosphatidylethanolamine. Furthermore, the composition of fatty acids in phosphatidylglycerol liposomes influenced the amount of antibiotics associated with liposomes; the highest amount was obtained with dioleoylphosphatidylglycerol followed by phosphatidylglycerol of fatty acid composition similar to that of egg yolk lecithin. It was established that purified liposomes, prepared from [3H]phosphatidylglycerol containing unsaturated fatty acid(s) bind about 25 per cent of originally present antibiotic. Both antibiotics, erythromycin A and azithromycin, were similar in respect to the amount of their association with liposomes. Determination of the size of phosphatidylglycerol/antibiotic liposomes established that the mean diameter of liposomes containing antibiotics was 200-350 nm, very close to that of liposomes without them.

The characterization of sugar beet pectin using the EcoSEC® GPC system coupled to multi-angle light scattering, quasi-elastic light scattering, and differential viscometry

USDA-ARS?s Scientific Manuscript database

The need to increase the use of low valued co-products derived from the processing of sugar beets has prompted the investigation of the structure of the pectin extracted from sugar beet pulp. The characterization of sugar beet pectin is essential as it has the potential to be used in the production ...

Role of nanoparticle size in self-assemble processes of collagen for tissue engineering application.

PubMed

Vedhanayagam, Mohan; Nidhin, Marimuthu; Duraipandy, Natarajan; Naresh, Niranjan Dhanasekar; Jaganathan, Ganesh; Ranganathan, Mohan; Kiran, Manikantan Syamala; Narayan, Shoba; Nair, Balachandran Unni; Sreeram, Kalarical Janardhanan

2017-06-01

Nanoparticle mediated extracellular matrix may offer new and improved biomaterial to wound healing and tissue engineering applications. However, influence of nanoparticle size in extracellular matrix is still unclear. In this work, we synthesized different size of silver nanoparticles (AgNPs) comprising of 10nm, 35nm and 55nm using nutraceuticals (pectin) as reducing as well as stabilization agents through microwave irradiation method. Synthesized Ag-pectin nanoparticles were assimilated in the self-assemble process of collagen leading to fabricated collagen-Ag-pectin nanoparticle based scaffolds. Physico-chemical properties and biocompatibility of scaffolds were analyzed through FT-IR, SEM, DSC, mechanical strength analyzer, antibacterial activity and MTT assay. Our results suggested that 10nm sized Ag-pectin nanoparticles significantly increased the denaturation temperature (57.83°C) and mechanical strength (0.045MPa) in comparison with native collagen (50.29°C and 0.011MPa). The in vitro biocompatibility assay reveals that, collagen-Ag-pectin nanoparticle based scaffold provided higher antibacterial activity against to Gram positive and Gram negative as well as enhanced cell viability toward keratinocytes. This work opens up a possibility of employing the pectin caged silver nanoparticles to develop collagen-based nanoconstructs for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Sequential extraction of flavonoids and pectin from yellow passion fruit rind using pressurized solvent or ultrasound.

PubMed

de Souza, Caroline G; Rodrigues, Tigressa Hs; E Silva, Lorena Ma; Ribeiro, Paulo Rv; de Brito, Edy S

2018-03-01

Passion fruit rind (PFR) represents 90% of the total fruit weight and is wasted during juice processing. Passion fruit rind is known to contain flavonoids and pectin. An alternative use for this fruit juice industrial residue is to obtain these compounds. This study aimed to verify the influence of pressurized solvent extraction (PSE) or ultrasound assisted extraction (UAE) of flavonoid and pectin in a sequential process. The PSE using ethanol at 60:40 (v/v) yielded a total polyphenol content of 4.67 g GAE kg -1 PFR, orientin-7-O-glucoside (1.57 g kg -1 PFR) and luteolin-6-C-glucoside (2.44 g kg -1 PFR). Pectin yield was 165 g kg -1 PFR, either in PSE or UAE. Pectin characterization indicates that the pectic structure has basically homogalacturonans and galacturonate followed by a galacturonic acid ester unit, with methylation degree of 70%. With this study it can be concluded that mixtures of alcohols with water favor the extraction of bioactive compounds of passion fruit peel. Both PSE and UAE were effective in sequentially extracting flavonoids and pectin. The preferred solvent is ethanol due to its lower toxicity. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Requirement for Pectin Methyl Esterase and Preference for Fragmented over Native Pectins for Wall-associated Kinase-activated, EDS1/PAD4-dependent Stress Response in Arabidopsis*

PubMed Central

Kohorn, Bruce D.; Kohorn, Susan L.; Saba, Nicholas J.; Martinez, Victoriano Meco

2014-01-01

The wall-associated kinases (WAKs) have a cytoplasmic protein kinase domain that spans the plasma membrane and binds pectin in the extracellular matrix of plants. WAKs are required for cell expansion during Arabidopsis seedling development but are also an integral part of the response to pathogens and stress that present oligogalacturonides (OGs), which subsequently bind to WAKs and activate a MPK6 (mitogen-activated protein kinase)-dependent pathway. It was unclear how WAKs distinguish native pectin polymers and OGs to activate one or the other of these two pathways. A dominant allele of WAK2 constitutively activates the stress response, and we show here that the effect is dependent upon EDS1 and PAD4, transcriptional activators involved in the pathogen response. Moreover, the WAK2 dominant allele is suppressed by a null allele of a pectin methyl esterase (PME3) whose activity normally leads to cross-linking of pectins in the cell wall. Although OGs activate a transcriptional response in wild type, the response is enhanced in a pme3/pme3 null, consistent with a competition by OG and native polymers for activation of WAKs. This provides a plausible mechanism for WAKs to distinguish an expansion from a stress pathway. PMID:24855660

Enhancement in in vitro anti-angiogenesis activity and cytotoxicity in lung cancer cell by pectin-PVP based curcumin particulates.

PubMed

Gaikwad, Dinanath; Shewale, Rajnita; Patil, Vinit; Mali, Dipak; Gaikwad, Uday; Jadhav, Namdeo

2017-11-01

The aim of this work was to prepare pectin-poly (vinyl pyrrolidone) [PVP] based curcumin particulates to enhance the anticancer potential of curcumin, solubility and allow its localized controlled release. Pectin-PVP based curcumin particulates (PECTIN-PVP CUR) were prepared by spray drying technique in different ratios and were evaluated for surface morphology, micromeritics, flowability, particle size, drug content, in vitro dissolution, inhalable fraction, anti-angiogenesis/angiolysis and cytotoxicity. Results of micromeritic properties, Carr's index, Hausner's ratio and angle of repose were satisfactory. The batch CP3 was considered as optimum, due to excellent flowability, acceptable aggregation and enhanced solubility. The particle size and size distribution data of selected batch CP3 showed 90% of curcumin particulates having size less than 2.74μm, which may deposit to lungs. Twin Impinger studies showed that 29% of respirable fraction was generated, which could be directly delivered to lungs. The in vitro dissolution data showed many fold increase in dissolution rate. Angiolytic activity and MTT assay of PECTIN-PVP CUR have demonstrated enhancement in the anti-tumor potential, compared to curcumin alone. Altogether, PECTIN-PVP CUR were found suitable for local delivery and enhance its anticancer potential of curcumin. Copyright © 2017 Elsevier B.V. All rights reserved.

A Proteomic Study of Pectin Degrading Enzymes Secreted by Botrytis cinerea Grown in Liquid Culture

PubMed Central

Shah, Punit; Gutierrez-Sanchez, Gerardo; Orlando, Ron; Bergmann, Carl

2009-01-01

Botrytis cinerea is a pathogenic filamentous fungus which infects more than 200 plant species. The enzymes secreted by B. cinerea play an important role in the successful colonization of a host plant. Some of the secreted enzymes are involved in the degradation of pectin, a major component of the plant cell wall. A total of 126 proteins secreted by B. cinerea were identified by growing the fungus on highly or partially esterified pectin, or on sucrose in liquid culture. Sixty-seven common proteins were identified in each of the growth conditions, of which 50 proteins exhibited a Signal P motif. Thirteen B. cinerea proteins with functions related to pectin degradation were identified in both pectin growth conditions, while only four were identified in sucrose. Our results indicate it is unlikely that the activation of B. cinerea from the dormant state to active infection is solely dependent on changes in the degree of esterification of the pectin component of the plant cell wall. Further, these results suggest that future studies of the B. cinerea secretome in infections of ripe and unripe fruits will provide important information that will describe the mechanisms that the fungus employs to access nutrients and decompose tissues. PMID:19526562

Wound-induced pectin methylesterases enhance banana (Musa spp. AAA) susceptibility to Fusarium oxysporum f. sp. cubense

PubMed Central

Ma, Li; Jiang, Shuang; Lin, Guimei; Cai, Jianghua; Ye, Xiaoxi; Chen, Houbin; Li, Minhui; Li, Huaping; Takáč, Tomáš; Šamaj, Jozef; Xu, Chunxiang

2013-01-01

Recent studies suggest that plant pectin methylesterases (PMEs) are directly involved in plant defence besides their roles in plant development. However, the molecular mechanisms of PME action on pectins are not well understood. In order to understand how PMEs modify pectins during banana (Musa spp.)–Fusarium interaction, the expression and enzyme activities of PMEs in two banana cultivars, highly resistant or susceptible to Fusarium, were compared with each other. Furthermore, the spatial distribution of PMEs and their effect on pectin methylesterification of 10 individual homogalacturonan (HG) epitopes with different degrees of methylesterification (DMs) were also examined. The results showed that, before pathogen treatment, the resistant cultivar displayed higher PME activity than the susceptible cultivar, corresponding well to the lower level of pectin DM. A significant increase in PME expression and activity and a decrease in pectin DM were observed in the susceptible cultivar but not in the resistant cultivar when plants were wounded, which was necessary for successful infection. With the increase of PME in the wounded susceptible cultivar, the JIM5 antigen (low methyestrified HGs) increased. Forty-eight hours after pathogen infection, the PME activity and expression in the susceptible cultivar were higher than those in the resistant cultivar, while the DM was lower. In conclusion, the resistant and the susceptible cultivars differ significantly in their response to wounding. Increased PMEs and thereafter decreased DMs acompanied by increased low methylesterified HGs in the root vascular cylinder appear to play a key role in determination of banana susceptibility to Fusarium. PMID:23580752

Wound-induced pectin methylesterases enhance banana (Musa spp. AAA) susceptibility to Fusarium oxysporum f. sp. cubense.

PubMed

Ma, Li; Jiang, Shuang; Lin, Guimei; Cai, Jianghua; Ye, Xiaoxi; Chen, Houbin; Li, Minhui; Li, Huaping; Takác, Tomás; Samaj, Jozef; Xu, Chunxiang

2013-05-01

Recent studies suggest that plant pectin methylesterases (PMEs) are directly involved in plant defence besides their roles in plant development. However, the molecular mechanisms of PME action on pectins are not well understood. In order to understand how PMEs modify pectins during banana (Musa spp.)-Fusarium interaction, the expression and enzyme activities of PMEs in two banana cultivars, highly resistant or susceptible to Fusarium, were compared with each other. Furthermore, the spatial distribution of PMEs and their effect on pectin methylesterification of 10 individual homogalacturonan (HG) epitopes with different degrees of methylesterification (DMs) were also examined. The results showed that, before pathogen treatment, the resistant cultivar displayed higher PME activity than the susceptible cultivar, corresponding well to the lower level of pectin DM. A significant increase in PME expression and activity and a decrease in pectin DM were observed in the susceptible cultivar but not in the resistant cultivar when plants were wounded, which was necessary for successful infection. With the increase of PME in the wounded susceptible cultivar, the JIM5 antigen (low methyestrified HGs) increased. Forty-eight hours after pathogen infection, the PME activity and expression in the susceptible cultivar were higher than those in the resistant cultivar, while the DM was lower. In conclusion, the resistant and the susceptible cultivars differ significantly in their response to wounding. Increased PMEs and thereafter decreased DMs acompanied by increased low methylesterified HGs in the root vascular cylinder appear to play a key role in determination of banana susceptibility to Fusarium.

Expression of mung bean pectin acetyl esterase in potato tubers: effect on acetylation of cell wall polymers and tuber mechanical properties.

PubMed

Orfila, Caroline; Dal Degan, Florence; Jørgensen, Bodil; Scheller, Henrik Vibe; Ray, Peter M; Ulvskov, Peter

2012-07-01

A mung bean (Vigna radiata) pectin acetyl esterase (CAA67728) was heterologously expressed in tubers of potato (Solanum tuberosum) under the control of the granule-bound starch synthase promoter or the patatin promoter in order to probe the significance of O-acetylation on cell wall and tissue properties. The recombinant tubers showed no apparent macroscopic phenotype. The enzyme was recovered from transgenic tubers using a high ionic strength buffer and the extract was active against a range of pectic substrates. Partial in vivo de-acetylation of cell wall polysaccharides occurred in the transformants, as shown by a 39% decrease in the degree of acetylation (DA) of tuber cell wall material (CWM). Treatment of CWM using a combination of endo-polygalacturonase and pectin methyl esterase extracted more pectin polymers from the transformed tissue compared to wild type. The largest effect of the pectin acetyl esterase (68% decrease in DA) was seen in the residue from this extraction, suggesting that the enzyme is preferentially active on acetylated pectin that is tightly bound to the cell wall. The effects of acetylation on tuber mechanical properties were investigated by tests of failure under compression and by determination of viscoelastic relaxation spectra. These tests suggested that de-acetylation resulted in a stiffer tuber tissue and a stronger cell wall matrix, as a result of changes to a rapidly relaxing viscoelastic component. These results are discussed in relation to the role of pectin acetylation in primary cell walls and its implications for industrial uses of potato fibres.

Phase I clinical trial of O-Acetylated pectin conjugate, a plant polysaccharide based typhoid vaccine

PubMed Central

Szu, Shousun C.; Lin, Kimi F-Y; Hunt, Steven; Chu, Chiayung; Thinh, Nguyen Duc

2014-01-01

Background Typhoid fever remains an important cause of morbidity and mortality in the developing countries. Vi capsular polysaccharide conjugate vaccine demonstrated safety and efficacy in young children in high endemic regions. A novel typhoid conjugate vaccine based on plant polysaccharide pectin was studied in a phase I trial. Methods Fruit pectin, having the same carbohydrate backbone structure as Vi, was purified from citrus peel and used as the polysaccharide source to prepare a semi-synthetic typhoid conjugate vaccine. Pectin was chemically O-acetylated (OAcPec) to antigenically resemble Vi and conjugated to carrier protein rEPA, a recombinant exoprotein A from Pseudomonas aeruginosa. 25 healthy volunteers, 18–45 years old, were injected once with OAcPec-rEPA. Safety and IgG antibodies reactive with Vi and pectin were analyzed. Results No vaccine associated serious adverse reaction was reported. Six weeks after the injection of OAcPec-rEPA, 64% of the volunteers elicited >4 fold rise of anti-Vi IgG. At 26 weeks the level declined, but the difference between the levels at 6 and 26 weeks are not statistically significant. There is a direct correlation between the level of anti-Vi IgG before and after the injection (R2 = 0.96). The anti-Vi IgG can be absorbed by Vi, but not by pectin. There was no corresponding increase of anti-pectin after the injection, indicating the antibody response to OAcPec-rEPA was specific to Vi. There is no Vi-rEPA data in US adults for comparison of immune responses. The OAcPec-rEPA elicited significantly less IgG anti-Vi in US adults than those by Vi-rEPA in Vietnamese adults. Conclusion The O-acetylated pectin conjugate, a plant based typhoid vaccine, is safe and immunogenic in adult volunteers. PMID:24657719

Identification of Pectin Degrading Enzymes Secreted by Xanthomonas oryzae pv. oryzae and Determination of Their Role in Virulence on Rice.

PubMed

Tayi, Lavanya; Maku, Roshan V; Patel, Hitendra Kumar; Sonti, Ramesh V

2016-01-01

Xanthomonas oryzae pv.oryzae (Xoo) causes the serious bacterial blight disease of rice. Xoo secretes a repertoire of plant cell wall degrading enzymes (CWDEs) like cellulases, xylanases, esterases etc., which act on various components of the rice cell wall. The major cellulases and xylanases secreted by Xoo have been identified and their role in virulence has been determined. In this study, we have identified some of the pectin degrading enzymes of Xoo and assessed their role in virulence. Bioinformatics analysis indicated the presence of four pectin homogalacturonan (HG) degrading genes in the genome of Xoo. The four HG degrading genes include one polygalacturonase (pglA), one pectin methyl esterase (pmt) and two pectate lyases (pel and pelL). There was no difference in the expression of pglA, pmt and pel genes by laboratory wild type Xoo strain (BXO43) grown in either nutrient rich PS medium or in plant mimic XOM2 medium whereas the expression of pelL gene was induced in XOM2 medium as indicated by qRT-PCR experiments. Gene disruption mutations were generated in each of these four genes. The polygalacturonase mutant pglA- was completely deficient in degrading the substrate Na-polygalacturonicacid (PGA). Strains carrying mutations in the pmt, pel and pelL genes were as efficient as wild type Xoo (BXO43) in cleaving PGA. These observations clearly indicate that PglA is the major pectin degrading enzyme produced by Xoo. The pectin methyl esterase, Pmt, is the pectin de-esterifying enzyme secreted by Xoo as evident from the enzymatic activity assay performed using pectin as the substrate. Mutations in the pglA, pmt, pel and pelL genes have minimal effects on virulence. This suggests that, as compared to cellulases and xylanases, the HG degrading enzymes may not have a major role in the pathogenicity of Xoo.

Identification of Pectin Degrading Enzymes Secreted by Xanthomonas oryzae pv. oryzae and Determination of Their Role in Virulence on Rice

PubMed Central

Tayi, Lavanya; Maku, Roshan V.; Patel, Hitendra Kumar; Sonti, Ramesh V.

2016-01-01

Xanthomonas oryzae pv.oryzae (Xoo) causes the serious bacterial blight disease of rice. Xoo secretes a repertoire of plant cell wall degrading enzymes (CWDEs) like cellulases, xylanases, esterases etc., which act on various components of the rice cell wall. The major cellulases and xylanases secreted by Xoo have been identified and their role in virulence has been determined. In this study, we have identified some of the pectin degrading enzymes of Xoo and assessed their role in virulence. Bioinformatics analysis indicated the presence of four pectin homogalacturonan (HG) degrading genes in the genome of Xoo. The four HG degrading genes include one polygalacturonase (pglA), one pectin methyl esterase (pmt) and two pectate lyases (pel and pelL). There was no difference in the expression of pglA, pmt and pel genes by laboratory wild type Xoo strain (BXO43) grown in either nutrient rich PS medium or in plant mimic XOM2 medium whereas the expression of pelL gene was induced in XOM2 medium as indicated by qRT-PCR experiments. Gene disruption mutations were generated in each of these four genes. The polygalacturonase mutant pglA- was completely deficient in degrading the substrate Na-polygalacturonicacid (PGA). Strains carrying mutations in the pmt, pel and pelL genes were as efficient as wild type Xoo (BXO43) in cleaving PGA. These observations clearly indicate that PglA is the major pectin degrading enzyme produced by Xoo. The pectin methyl esterase, Pmt, is the pectin de-esterifying enzyme secreted by Xoo as evident from the enzymatic activity assay performed using pectin as the substrate. Mutations in the pglA, pmt, pel and pelL genes have minimal effects on virulence. This suggests that, as compared to cellulases and xylanases, the HG degrading enzymes may not have a major role in the pathogenicity of Xoo. PMID:27907079

A novel bifunctional pectinase from Penicillium oxalicum SX6 with separate pectin methylesterase and polygalacturonase catalytic domains.

PubMed

Tu, Tao; Bai, Yingguo; Luo, Huiying; Ma, Rui; Wang, Yaru; Shi, Pengjun; Yang, Peilong; Meng, Kun; Yao, Bin

2014-06-01

A multimodular pectinase of glycoside hydrolase family 28, S6A, was identified in Penicillium oxalicum SX6 that consists of an N-terminal catalytic domain of pectin methylesterase, a Thr/Ser-rich linker region, and a C-terminal catalytic domain of polygalacturonase. Recombinant S6A and its two derivatives, S6PE (the catalytic domain of pectin methylesterase) and S6PG (the catalytic domain of polygalacturonase), were produced in Pichia pastoris. S6A was a bifunctional protein and had both pectin methylesterase and polygalacturonase activities. Three enzymes showed similar biochemical properties, such as optimal pH and temperature (pH 5.0 and 50 °C) and excellent stability at pH 3.5-6.0 and 40 °C. Most metal ions tested (Na(+), K(+), Ca(2+), Li(+), Co(2+), Cr(3+), Ni(2+), Cu(2+), Mn(2+),Mg(2+), Fe(3+), Zn(2+), and Pb(2+)) enhanced the pectin methylesterase activities of S6PE and S6A, but had little or inhibitory effects on the polygalacturonase activities of S6A and S6PG. In comparison with most fungal pectin methylesterases, S6A had higher specific activity (271.1 U/mg) towards 70 % DM citrus pectin. When S6PE and S6PG were combined at the activity ratio of 1:4, the most significant synergistic effect was observed in citrus pectin degradation and degumming of sisal fiber, which is comparable with the performance of S6A (95 v.s. 100 % and 16.9 v.s. 17.2 %, respectively). To the best of our knowledge, this work represents the first report of gene cloning, heterologous expression, and biochemical characterization of a bifunctional pectinase with separate catalytic domains.

Boron-bridged RG-II and calcium are required to maintain the pectin network of the Arabidopsis seed mucilage ultrastructure.

PubMed

Shi, Da-Chuan; Wang, Juan; Hu, Rui-Bo; Zhou, Gong-Ke; O'Neill, Malcolm A; Kong, Ying-Zhen

2017-06-01

The structure of a pectin network requires both calcium (Ca 2+ ) and boron (B). Ca 2+ is involved in crosslinking pectic polysaccharides and arbitrarily induces the formation of an "egg-box" structure among pectin molecules, while B crosslinks rhamnogalacturonan II (RG-II) side chain A apiosyl residues in primary cell walls to generate a borate-dimeric-rhamnogalacturonan II (dRG-II-B) complex through a boron-bridge bond, leading to the formation of a pectin network. Based on recent studies of dRG-II-B structures, a hypothesis has been proposed suggesting that Ca 2+ is a common component of the dRG-II-B complex. However, no in vivo evidence has addressed whether B affects the stability of Ca 2+ crosslinks. Here, we investigated the L-fucose-deficient dwarf mutant mur1, which was previously shown to require exogenous B treatment for phenotypic reversion. Imbibed Arabidopsis thaliana seeds release hydrated polysaccharides to form a halo of seed mucilage covering the seed surface, which consists of a water-soluble outer layer and an adherent inner layer. Our study of mur1 seed mucilage has revealed that the pectin in the outer layer of mucilage was relocated to the inner layer. Nevertheless, the mur1 inner mucilage was more vulnerable to rough shaking or ethylene diamine tetraacetic acid (EDTA) extraction than that of the wild type. Immunolabeling analysis suggested that dRG-II-B was severely decreased in mur1 inner mucilage. Moreover, non-methylesterified homogalacturonan (HG) exhibited obvious reassembly in the mur1 inner layer compared with the wild type, which may imply a possible connection between dRG-II-B deficiency and pectin network transformation in the seed mucilage. As expected, the concentration of B in the mur1 inner mucilage was reduced, whereas the distribution and concentration of Ca 2+ in the inner mucilage increased significantly, which could be the reason why pectin relocates from the outer mucilage to the inner mucilage. Consequently, the disruption of B bridges appears to result in the extreme sensitivity of the mur1 mucilage pectin complex to EDTA extraction, despite the reinforcement of the pectin network by excessive Ca 2+ . Therefore, we propose a hypothesis that B, in the form of dRG-II-B, works together with Ca 2+ to maintain pectin network crosslinks and ultimately the mucilage ultrastructure in seed mucilage. This work may serve to complement our current understanding of mucilage configuration.

Investigation of the interface in silica-encapsulated liposomes by combining solid state NMR and first principles calculations.

PubMed

Folliet, Nicolas; Roiland, Claire; Bégu, Sylvie; Aubert, Anne; Mineva, Tzonka; Goursot, Annick; Selvaraj, Kaliaperumal; Duma, Luminita; Tielens, Frederik; Mauri, Francesco; Laurent, Guillaume; Bonhomme, Christian; Gervais, Christel; Babonneau, Florence; Azaïs, Thierry

2011-10-26

In the context of nanomedicine, liposils (liposomes and silica) have a strong potential for drug storage and release schemes: such materials combine the intrinsic properties of liposome (encapsulation) and silica (increased rigidity, protective coating, pH degradability). In this work, an original approach combining solid state NMR, molecular dynamics, first principles geometry optimization, and NMR parameters calculation allows the building of a precise representation of the organic/inorganic interface in liposils. {(1)H-(29)Si}(1)H and {(1)H-(31)P}(1)H Double Cross-Polarization (CP) MAS NMR experiments were implemented in order to explore the proton chemical environments around the silica and the phospholipids, respectively. Using VASP (Vienna Ab Initio Simulation Package), DFT calculations including molecular dynamics, and geometry optimization lead to the determination of energetically favorable configurations of a DPPC (dipalmitoylphosphatidylcholine) headgroup adsorbed onto a hydroxylated silica surface that corresponds to a realistic model of an amorphous silica slab. These data combined with first principles NMR parameters calculations by GIPAW (Gauge Included Projected Augmented Wave) show that the phosphate moieties are not directly interacting with silanols. The stabilization of the interface is achieved through the presence of water molecules located in-between the head groups of the phospholipids and the silica surface forming an interfacial H-bonded water layer. A detailed study of the (31)P chemical shift anisotropy (CSA) parameters allows us to interpret the local dynamics of DPPC in liposils. Finally, the VASP/solid state NMR/GIPAW combined approach can be extended to a large variety of organic-inorganic hybrid interfaces.

Physicochemical properties and antioxidant activity of gamma-oryzanol-loaded liposome formulations for topical use.

PubMed

Viriyaroj, Amornrat; Ngawhirunpat, Tanasait; Sukma, Monrudee; Akkaramongkolporn, Prasert; Ruktanonchai, Uracha; Opanasopit, Praneet

2009-01-01

The objective of this study is to prepare the gamma-oryzanol-loaded liposomes and investigate their physicochemical properties and antioxidant activity intended for cosmetic applications. Liposomes, Composing phosphatidylCholine (PC) and Cholesterol (Chol), CHAPS or sodium taurocholate (NaTC) were prepared by sonication method. Gamma-oryzanol-loaded liposomes were prepared by using 3, 5 and 10% gamma-oryzanol as an initial concentration. The formulation factors in a particular type and composition of lipid and initial drug loading on the physicochemical properties (i.e., particle size, zeta potential, entrapment efficiency, drug release) and antioxidant activity were studied. The particle sizes of bare liposomes were in nanometer range. The gamma-oryzanol-loaded liposomes in formulations of PC/CHAPS and PC/NaTC liposomes were smaller than PC/Chol liposomes. The incorporation efficiency of 10% gamma-oryzanol-loaded PC/Chol liposomes was less than gamma-oryzanol-loaded PC/CHAPS liposomes and PC/NaTC liposomes allowing higher in vitro release rate due to higher free gamma-oryzanol in buffer solution. The antioxidant activity of gamma-oryzanol-loaded liposomes was not different from pure gamma-oryzanol. Both gamma-oryzanol-loaded PC/CHAPS liposomes and PC/NaTC liposomes were showed to enhance the antioxidant activity in NHF cells. gamma-oryzanol-loaded PC/Chol liposomes demonstrated the lowest cytotoxicity in NHF cells. It was conceivably concluded that liposomes prepared in this study are suitable for gamma-oryzanol incorporation without loss of antioxidant activity.

From conventional to stealth liposomes: a new frontier in cancer chemotherapy.

PubMed

Cattel, Luigi; Ceruti, Maurizio; Dosio, Franco

2003-01-01

Many attempts have been made to achieve good selectivity to targeted tumor cells by preparing specialized carrier agents that are therapeutically profitable for anticancer therapy. Among these, liposomes are the most studied colloidal particles thus far applied in medicine and in particular in antitumor therapy. Although they were first described in the 1960s, only at the beginning of 1990s did the first therapeutic liposomes appear on the market. The first-generation liposomes (conventional liposomes) comprised a liposome-containing amphotericin B, Ambisome (Nexstar, Boulder, CO, USA), used as an antifungal drug, and Myocet (Elan Pharma Int, Princeton, NJ, USA), a doxorubicin-containing liposome, used in clinical trials to treat metastatic breast cancer. The second-generation liposomes ("pure lipid approach") were long-circulating liposomes, such as Daunoxome, a daunorubicin-containing liposome approved in the US and Europe to treat AIDS-related Kaposi's sarcoma. The third-generation liposomes were surface-modified liposomes with gangliosides or sialic acid, which can evade the immune system responsible for removing liposomes from circulation. The fourth-generation liposomes, pegylated liposomal doxorubicin, were called "stealth liposomes" because of their ability to evade interception by the immune system, in the same way as the stealth bomber was able to evade radar. Actually, the only stealth liposome on the market is Caelyx/Doxil (Schering-Plough, Madison NJ, USA), used to cure AIDS-related Kaposi's sarcoma, resistant ovarian cancer and metastatic breast cancer. Pegylated liposomal doxorubicin is characterized by a very long-circulation half-life, favorable pharmacokinetic behavior and specific accumulation in tumor tissues. These features account for the much lower toxicity shown by Caelyx in comparison to free doxorubicin, in terms of cardiotoxicity, vesicant effects, nausea, vomiting and alopecia. Pegylated liposomal doxorubicin also appeared to be less myelotoxic than doxorubicin. Typical forms of toxicity associated to it are acute infusion reaction, mucositis and palmar plantar erythrodysesthesia, which occur especially at high doses or short dosing intervals. Active and cell targeted liposomes can be obtained by attaching some antigen-directed monoclonal antibodies (Moab or Moab fragments) or small proteins and molecules (folate, epidermal growth factor, transferrin) to the distal end of polyethylene glycol in pegylated liposomal doxorubicin. The most promising therapeutic application of liposomes is as non-viral vector agents in gene therapy, characterized by the use of cationic phospholipids complexed with the negatively charged DNA plasmid. The use of liposome formulations in local-regional anticancer therapy is also discussed. Finally, pegylated liposomal doxorubicin containing radionuclides are used in clinical trials as tumor-imaging agents or in positron emission tomography.

Complexes containing cationic and anionic pH-sensitive liposomes: comparative study of factors influencing plasmid DNA gene delivery to tumors.

PubMed

Chen, Yan; Sun, Ji; Lu, Ying; Tao, Chun; Huang, Jingbin; Zhang, He; Yu, Yuan; Zou, Hao; Gao, Jing; Zhong, Yanqiang

2013-01-01

pH-sensitive liposomes represent an effective gene vector in cancer therapy. However, their use is greatly hampered by their relatively low transfection efficiency. To improve the transfection efficiency of pH-sensitive liposomes, we prepared complexes containing 3β-[N-(N',N'-dimethylaminoethane) carbamoyl] cholesterol (DC-Chol) and dioleoylphosphatidyl ethanolamine (DOPE) liposomes and pH-sensitive liposomes composed of cholesteryl hemisuccinate (CHEMS) and DOPE, and evaluated the influence of various factors on plasmid DNA (pDNA) transfection efficiency. All DC-Chol/DOPE liposome/pDNA and pH-sensitive liposome complexes showed similarly potent pH sensitivity. In the presence of serum-containing medium, two optimized complexes of DC-Chol/DOPE liposomes/pDNA and pH-sensitive PEGylated liposomes showed high transfection efficiency of 22.94% and 20.07%, respectively. Notably, DC-Chol/DOPE (2:3) liposomes/pH-sensitive PEGylated (1%) liposome complexes with a charge ratio of 1:1 (m/m [+/-]) showed enhanced accumulation in tumors in vivo. Our results show the influence of various factors on pDNA transfection efficiency in complexes of DC-Chol/DOPE liposomes and pH-sensitive PEGylated liposomes. Understanding of such mechanisms will lead to better design of complexes of DC-Chol/DOPE liposomes and pH-sensitive liposomes for gene therapy.

Complexes containing cationic and anionic pH-sensitive liposomes: comparative study of factors influencing plasmid DNA gene delivery to tumors

PubMed Central

Chen, Yan; Sun, Ji; Lu, Ying; Tao, Chun; Huang, Jingbin; Zhang, He; Yu, Yuan; Zou, Hao; Gao, Jing; Zhong, Yanqiang

2013-01-01

pH-sensitive liposomes represent an effective gene vector in cancer therapy. However, their use is greatly hampered by their relatively low transfection efficiency. To improve the transfection efficiency of pH-sensitive liposomes, we prepared complexes containing 3β-[N-(N′,N′-dimethylaminoethane) carbamoyl] cholesterol (DC-Chol) and dioleoylphosphatidyl ethanolamine (DOPE) liposomes and pH-sensitive liposomes composed of cholesteryl hemisuccinate (CHEMS) and DOPE, and evaluated the influence of various factors on plasmid DNA (pDNA) transfection efficiency. All DC-Chol/DOPE liposome/pDNA and pH-sensitive liposome complexes showed similarly potent pH sensitivity. In the presence of serum-containing medium, two optimized complexes of DC-Chol/DOPE liposomes/pDNA and pH-sensitive PEGylated liposomes showed high transfection efficiency of 22.94% and 20.07%, respectively. Notably, DC-Chol/DOPE (2:3) liposomes/pH-sensitive PEGylated (1%) liposome complexes with a charge ratio of 1:1 (m/m [+/−]) showed enhanced accumulation in tumors in vivo. Our results show the influence of various factors on pDNA transfection efficiency in complexes of DC-Chol/DOPE liposomes and pH-sensitive PEGylated liposomes. Understanding of such mechanisms will lead to better design of complexes of DC-Chol/DOPE liposomes and pH-sensitive liposomes for gene therapy. PMID:23637529

Doped colorimetric assay liposomes

DOEpatents

Charych, Deborah; Stevens, Raymond C.

2001-01-01

The present invention provides compositions comprising colorimetric assay liposomes. The present invention also provides methods for producing colorimetric liposomes and calorimetric liposome assay systems. In preferred embodiments, these calorimetric liposome systems provide high levels of sensitivity through the use of dopant molecules. As these dopants allow the controlled destabilization of the liposome structure, upon exposure of the doped liposomes to analyte(s) of interest, the indicator color change is facilitated and more easily recognized.

Entrapment of ovalbumin into liposomes--factors affecting entrapment efficiency, liposome size, and zeta potential.

PubMed

Brgles, Marija; Jurasin, Darija; Sikirić, Maja Dutour; Frkanec, Ruza; Tomasić, Jelka

2008-01-01

Various amounts of Ovalbumin (OVA) were encapsulated into positively and negatively charged multilamellar liposomes, with the aim to investigate the entrapment efficiency in different buffers and to study their effects on the liposome size and zeta potential. Results showed that the entrapment efficiency of OVA in anionic liposomes was the same in 10 mM Phosphate Buffer (PB) as in Phosphate-Buffered Saline (PBS; PB + 0.15 M NaCl). Also, liposome size was approximately 1200 nm for all anionic liposomes incorporating OVA. The entrapment efficiency of OVA in cationic liposomes was highly dependent on ionic strength. The size of cationic liposomes was approximately 1200 nm in PBS, regardless of protein content, but increased with the amount of the incorporated protein in PB. Aggregation of cationic liposomes in PB was observed when the mass of the protein was 2.5 mg or greater. The zeta potential of anionic liposomes was negative and of cationic liposomes positive in the whole range of protein mass tested. These results show how different compositions of lipid and aqueous phases can be used to vary the entrapment efficiency, liposome size, and zeta potential--the factors that are of great importance for the use of liposomes as drug carriers.

Surface functionalization of liposomes with proteins and carbohydrates for use in anti-cancer applications

NASA Astrophysics Data System (ADS)

Platt, Virginia M.

Liposomes can be used to exploit the altered biology of cancer thereby increasing delivery of liposome-associated anti-cancer drugs. In this dissertation, I explore methods that utilize the unique cancer expression of the polymeric glycosaminoglycan hyaluronan (HA) and the HA receptor CD44 to target liposomes to tumors, using liposomes functionalized with proteins or oligosaccharides on their surface. To make it easier to prepare protein-functionalized liposomes, a non-covalent protein/liposome association method based upon metal chelation/his 6 interaction was devised and characterized. I evaluated non-covalent attachment of the prodrug converting enzyme yeast cytosine deaminase, the far-red fluorescent protein mKate, two antigens ovalbumin and the membrane proximal region of an HIV GAG and hyaluronidase, a HA-degrading enzyme. In Chapter 2, I describe the synthesis of hyaluronan-oligosaccharide (HA-O) lipid conjugates and their incorporation into liposomes to target CD44-overexpressing cancer cells. HA-O ligands of defined-length, up to 10 monosaccharides, were attached to lipids via various linkers by reductive amination. The HA-lipids were easily incorporated into liposomes but did not mediate binding of liposomes to CD44 overexpressing cells. In Chapter 3, I evaluate the capacity of tris-NTA-Ni-lipids incorporated within a liposome bilayer to associate with his6-tagged proteins. Tris-NTA-lipids of differing structures and avidities were used to associate yeast cytosine deaminase and mKate to the surface of liposomes. Two tris-NTA-lipids and a mono-NTA lipid associated his-tagged proteins to a 1:1 molar ratio in solution. The proteins remained active while associated with the liposome surface. When challenged in vitro with fetal calf serum, tris-NTA-containing liposomes retained his-tagged proteins longer than mono-NTA. However, the tris-NTA/his6 interaction was found to be in a dynamic state; free yeast cytosine deaminase rapidly competed with pre-bound mKate for NTA occupancy. In the circulation of mice, his-tagged proteins associated with NTA-liposomes were cleared as rapidly as free protein. In Chapter 4, I study the effect of NTA/his-tag avidity on immune response when NTA-containing liposomes are used as non-covalent, particulate adjuvants. Two his-tagged antigens, ovalbumin and the membrane proximal portion of HIV Gag, were associated with NTA-liposomes containing either mono-NTA or tris-NTA lipids. The immune response to each antigen was compared to control adjuvant formulations in which antigens were admixed with or covalently-conjugated to liposomes. The weaker antigen, the HIV Gag peptide, induced a stronger immune response when associated with NTA-containing liposomes than when admixed with liposomes. Ovalbumin preparations in which the protein was admixed with particles or non-covalently associated with NTA-liposomes elicited a higher immune response than free ovalbumin or ovalbumin admixed with the control adjuvant alum. For both antigens, NTA-liposome responses were less than the response to antigens covalently linked to the liposome. In Chapter 5, I evaluate the potential for hyaluronidase to target conjugated liposomes to tumors or improve liposome motility within hyaluronan-rich tumors. Ovine hyaluronidase was modified using iminothiolane to introduce sulfhydryl groups into the enzyme. The enzyme was attached to liposomes via maleimide lipids or to maleimidehis10 in order to engineer non-covalent NTA-liposome association. Enzyme activity was retained after sulfhydryl addition and after attachment to liposomes. Liposome-conjugated hyaluronidase degraded an HA-gel at the same rate as admixed liposomes. When hyaluronidase-liposomes were injected intravenously in mice, the hyaluronidase conjugated-liposomes experienced faster clearance than control liposomes but slower clearance than free hyaluronidase. As a whole, these studies may help develop universal methods for a range of protein therapeutics and anti-cancer targeting agents.

[Effect of pectin additives from cotton on the physical development, nutrition and erythrocytes in infants].

PubMed

Salomov, I T; Ashurov, A R; Oblakulov, Kh M; Salomov, U I; Dzhalilov, B M

1994-01-01

The authors examined 156 babies on bottle feeding or breast and bottle feeding against control group of 60 babies whose diets were identical with the study group except additional intake of cotton-boll pectin. The latter was used for the first time as a biologically active ingredient of infant food (1 g per 100 ml of infant milk or food 3 times a day for 45-60 days). As a result of the pectin addition the infants of the study group had better nutritional status and physical development, their erythrocytic system was superior to that of the controls. It is stated that the addition of cotton-boll pectin to baby diet is beneficial for their health.

Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wenlin; Zhang, Lian Ying; Zhao, Xi Juan

An adsorbent, citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward removal of methylene blue, was synthesized by a facile zinc chloride activation approach in this study. The materials hold a great potential for treatment of dye wastewater. - Graphical abstract: Citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward methylene blue removal. - Highlights: • Citrus pectin derived porous carbons (CPPCs) were synthesized a facile zinc chloride activation approach. • CPPCs had abundant macro/meso/micropores for trapping MB molecules. • CPPCs exhibited ultrahigh adsorption capacity, rapidmore » adsorption rate and good reusability toward removal of MB.« less

Evaluation of pH-responsive liposomes containing amino acid-based zwitterionic lipids for improving intracellular drug delivery in vitro and in vivo.

PubMed

Obata, Yosuke; Tajima, Shoji; Takeoka, Shinji

2010-03-03

We developed pH-responsive liposomes containing synthetic glutamic acid-based zwitterionic lipids and evaluated their properties both in vitro and in vivo with the aim of constructing an efficient liposome-based systemic drug delivery system. The glutamic acid-based lipids; 1,5-dihexadecyl N-glutamyl-L-glutamate (L1) and 1,5-dihexadecyl N,N-diglutamyl-lysyl-L-glutamate (L2) were synthesized as a pH-responsive component of liposomes that respond to endosomal pH. The zeta potential of liposomes containing L1 or L2 was positive when the solution pH was below 4.6 or 5.6, respectively, but negative at higher pH values. The pH-responsive liposomes showed improved fusogenic potential to an endosome-mimicking anionic membrane at acidic pH, where the zeta potential of the liposomes was positive. We then prepared doxorubicin (DOX)-encapsulating liposomes containing L1 or L2, and clarified by confocal microscopic studies that the contents were rapidly transferred into both the cytoplasm and nucleus. Release of DOX from the endosomes mediated by the pH-responsive liposomes dramatically inhibited cancer cell growth. The L2-liposomes were slightly more effective than L1-liposomes as a drug delivery system. Intravenously injected L2-liposomes displayed blood persistence comparable to that of conventional phospholipid (PC)-based liposomes. Indeed, the antitumor efficacy of L2-liposomes was higher than that of PC-based liposomes against a xenograft breast cancer tumor in vivo. Thus, the high performance of L2-liposomes results from both efficient intracellular drug delivery and comparable blood persistence in comparison with the conventional PC-based liposomes in vitro and in vivo. Copyright 2009 Elsevier B.V. All rights reserved.

Effect of Fatty Acyl Group and Sterol Composition on Sensitivity of Lecithin Liposomes to Imidazole Antimycotics

PubMed Central

Yamaguchi, Hideyo; Iwata, Kazuo

1979-01-01

The specific affinity for membrane lipids and the membrane selectivity of three imidazole derivatives, clotrimazole, miconazole, and econazole, were studied using various types of liposomes with respect to the lecithin fatty acyl group composition and the liposome content and composition of sterol as membrane models. The sensitivity of liposomes to these drugs was primarily dependent upon the lecithin fatty acyl group composition. With sterol-free liposome systems, each imidazole induced maximum release of trapped glucose as a marker from the unsaturated dioleoyl lecithin liposomes, minimum release from the saturated dipalmitoyl lecithin liposomes, and intermediate release from egg lecithin liposomes. The sensitivity of the dipalmitoyl lecithin liposomes to any imidazole drug was not influenced by the incorporation of cholesterol or ergosterol. On the other hand, clotrimazole-induced permeability changes of liposomes prepared from unsaturated dioleoyl lecithin or egg lecithin were greatly enhanced by the incorporation of ergosterol, whereas they were suppressed by cholesterol incorporation. The sensitivity of liposomes prepared from these unsaturated lecithins to miconazole and econazole was also augmented by ergosterol incorporation, although it was scarcely altered by cholesterol incorporation. Negatively charged liposomes were more sensitive to the three imidazole drugs than positively charged liposomes. PMID:525988

Effect of fatty acyl group and sterol composition on sensitivity of lecithin liposomes to imidazole antimycotics.

PubMed

Yamaguchi, H; Iwata, K

1979-05-01

The specific affinity for membrane lipids and the membrane selectivity of three imidazole derivatives, clotrimazole, miconazole, and econazole, were studied using various types of liposomes with respect to the lecithin fatty acyl group composition and the liposome content and composition of sterol as membrane models. The sensitivity of liposomes to these drugs was primarily dependent upon the lecithin fatty acyl group composition. With sterol-free liposome systems, each imidazole induced maximum release of trapped glucose as a marker from the unsaturated dioleoyl lecithin liposomes, minimum release from the saturated dipalmitoyl lecithin liposomes, and intermediate release from egg lecithin liposomes. The sensitivity of the dipalmitoyl lecithin liposomes to any imidazole drug was not influenced by the incorporation of cholesterol or ergosterol. On the other hand, clotrimazole-induced permeability changes of liposomes prepared from unsaturated dioleoyl lecithin or egg lecithin were greatly enhanced by the incorporation of ergosterol, whereas they were suppressed by cholesterol incorporation. The sensitivity of liposomes prepared from these unsaturated lecithins to miconazole and econazole was also augmented by ergosterol incorporation, although it was scarcely altered by cholesterol incorporation. Negatively charged liposomes were more sensitive to the three imidazole drugs than positively charged liposomes.

Encapsulation in the food industry: a review.

PubMed

Gibbs, B F; Kermasha, S; Alli, I; Mulligan, C N

1999-05-01

Encapsulation involves the incorporation of food ingredients, enzymes, cells or other materials in small capsules. Applications for this technique have increased in the food industry since the encapsulated materials can be protected from moisture, heat or other extreme conditions, thus enhancing their stability and maintaining viability. Encapsulation in foods is also utilized to mask odours or tastes. Various techniques are employed to form the capsules, including spray drying, spray chilling or spray cooling, extrusion coating, fluidized bed coating, liposome entrapment, coacervation, inclusion complexation, centrifugal extrusion and rotational suspension separation. Each of these techniques is discussed in this review. A wide variety of foods is encapsulated--flavouring agents, acids bases, artificial sweeteners, colourants, preservatives, leavening agents, antioxidants, agents with undesirable flavours, odours and nutrients, among others. The use of encapsulation for sweeteners such as aspartame and flavours in chewing gum is well known. Fats, starches, dextrins, alginates, protein and lipid materials can be employed as encapsulating materials. Various methods exist to release the ingredients from the capsules. Release can be site-specific, stage-specific or signalled by changes in pH, temperature, irradiation or osmotic shock. In the food industry, the most common method is by solvent-activated release. The addition of water to dry beverages or cake mixes is an example. Liposomes have been applied in cheese-making, and its use in the preparation of food emulsions such as spreads, margarine and mayonnaise is a developing area. Most recent developments include the encapsulation of foods in the areas of controlled release, carrier materials, preparation methods and sweetener immobilization. New markets are being developed and current research is underway to reduce the high production costs and lack of food-grade materials.

Aromaticity/Bulkiness of Surface Ligands to Promote the Interaction of Anionic Amphiphilic Gold Nanoparticles with Lipid Bilayers.

PubMed

Gao, Jinhong; Zhang, Ouyang; Ren, Jing; Wu, Chuanliu; Zhao, Yibing

2016-02-16

The presence of large hydrophobic aromatic residues in cell-penetrating peptides or proteins has been demonstrated to be advantageous for their cell penetration. This phenomenon has also been observed when AuNPs were modified with peptides containing aromatic amino acids. However, it is still not clear how the presence of hydrophobic and aromatic groups on the surface of anionic AuNPs affects their interaction with lipid bilayers. Here, we studied the interaction of a range of anionic amphiphilic AuNPs coated by different combinations of hydrophobic and anionic ligands with four different types of synthetic lipid vesicles. Our results demonstrated the important role of the surface aromatic or bulky groups, relative to the hydrocarbon chains, in the interaction of anionic AuNPs with lipid bilayers. Hydrophobic interaction itself arising from the insertion of aromatic/bulky ligands on the surface of AuNPs into lipid bilayers is sufficiently strong to cause overt disruption of lipid vesicles and cell membranes. Moreover, by comparing the results obtained from AuNPs coated with aromatic ligands and cyclohexyl ligands lacking aromaticity respectively, we demonstrated that the bulkiness of the terminal groups in hydrophobic ligands instead of the aromatic character might be more important to the interaction of AuNPs with lipid bilayers. Finally, we further correlated the observation on model liposomes with that on cell membranes, demonstrating that AuNPs that are more disruptive to the more negatively charged liposomes are also substantially more disruptive to cell membranes. In addition, our results revealed that certain cellular membrane domains that are more susceptible to disruption caused by hydrophobic interactions with nanoparticle surfaces might determine the threshold of AuNP-mediated cytotoxicity.

Potential effect of cationic liposomes on interactions with oral bacterial cells and biofilms.

PubMed

Sugano, Marika; Morisaki, Hirobumi; Negishi, Yoichi; Endo-Takahashi, Yoko; Kuwata, Hirotaka; Miyazaki, Takashi; Yamamoto, Matsuo

2016-01-01

Although oral infectious diseases have been attributed to bacteria, drug treatments remain ineffective because bacteria and their products exist as biofilms. Cationic liposomes have been suggested to electrostatically interact with the negative charge on the bacterial surface, thereby improving the effects of conventional drug therapies. However, the electrostatic interaction between oral bacteria and cationic liposomes has not yet been examined in detail. The aim of the present study was to examine the behavior of cationic liposomes and Streptococcus mutans in planktonic cells and biofilms. Liposomes with or without cationic lipid were prepared using a reverse-phase evaporation method. The zeta potentials of conventional liposomes (without cationic lipid) and cationic liposomes were -13 and 8 mV, respectively, and both had a mean particle size of approximately 180 nm. We first assessed the interaction between liposomes and planktonic bacterial cells with a flow cytometer. We then used a surface plasmon resonance method to examine the binding of liposomes to biofilms. We confirmed the binding behavior of liposomes with biofilms using confocal laser scanning microscopy. The interactions between cationic liposomes and S. mutans cells and biofilms were stronger than those of conventional liposomes. Microscopic observations revealed that many cationic liposomes interacted with the bacterial mass and penetrated the deep layers of biofilms. In this study, we demonstrated that cationic liposomes had higher affinity not only to oral bacterial cells, but also biofilms than conventional liposomes. This electrostatic interaction may be useful as a potential drug delivery system to biofilms.

Enhanced bactericidal potency of nanoliposomes by modification of the fusion activity between liposomes and bacterium.

PubMed

Ma, Yufan; Wang, Zhao; Zhao, Wen; Lu, Tingli; Wang, Rutao; Mei, Qibing; Chen, Tao

2013-01-01

Pseudomonas aeruginosa represents a good model of antibiotic resistance. These organisms have an outer membrane with a low level of permeability to drugs that is often combined with multidrug efflux pumps, enzymatic inactivation of the drug, or alteration of its molecular target. The acute and growing problem of antibiotic resistance of Pseudomonas to conventional antibiotics made it imperative to develop new liposome formulations to overcome these mechanisms, and investigate the fusion between liposome and bacterium. The rigidity, stability and charge properties of phospholipid vesicles were modified by varying the cholesterol, 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE), and negatively charged lipids 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol sodium salt (DMPG), 1,2-dimyristoyl-sn-glycero-3-phopho-L-serine sodium salt (DMPS), 1,2-dimyristoyl-sn-glycero-3-phosphate monosodium salt (DMPA), nature phosphatidylserine sodium salt from brain and nature phosphatidylinositol sodium salt from soybean concentrations in liposomes. Liposomal fusion with intact bacteria was monitored using a lipid-mixing assay. It was discovered that the fluid liposomes-bacterium fusion is not dependent on liposomal size and lamellarity. A similar degree of fusion was observed for liposomes with a particle size from 100 to 800 nm. The fluidity of liposomes is an essential pre-request for liposomes fusion with bacteria. Fusion was almost completely inhibited by incorporation of cholesterol into fluid liposomes. The increase in the amount of negative charges in fluid liposomes reduces fluid liposomes-bacteria fusion when tested without calcium cations due to electric repulsion, but addition of calcium cations brings the fusion level of fluid liposomes to similar or higher levels. Among the negative phospholipids examined, DMPA gave the highest degree of fusion, DMPS and DMPG had intermediate fusion levels, and PI resulted in the lowest degree of fusion. Furthermore, the fluid liposomal encapsulated tobramycin was prepared, and the bactericidal effect occurred more quickly when bacteria were cultured with liposomal encapsulated tobramycin. The bactericidal potency of fluid liposomes is dramatically enhanced with respect to fusion ability when the fusogenic lipid, DOPE, is included. Regardless of changes in liposome composition, fluid liposomes-bacterium fusion is universally enhanced by calcium ions. The information obtained in this study will increase our understanding of fluid liposomal action mechanisms, and help in optimizing the new generation of fluid liposomal formulations for the treatment of pulmonary bacterial infections.

Enhanced bactericidal potency of nanoliposomes by modification of the fusion activity between liposomes and bacterium

PubMed Central

Ma, Yufan; Wang, Zhao; Zhao, Wen; Lu, Tingli; Wang, Rutao; Mei, Qibing; Chen, Tao

2013-01-01

Background Pseudomonas aeruginosa represents a good model of antibiotic resistance. These organisms have an outer membrane with a low level of permeability to drugs that is often combined with multidrug efflux pumps, enzymatic inactivation of the drug, or alteration of its molecular target. The acute and growing problem of antibiotic resistance of Pseudomonas to conventional antibiotics made it imperative to develop new liposome formulations to overcome these mechanisms, and investigate the fusion between liposome and bacterium. Methods The rigidity, stability and charge properties of phospholipid vesicles were modified by varying the cholesterol, 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE), and negatively charged lipids 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol sodium salt (DMPG), 1,2-dimyristoyl-sn-glycero-3-phopho-L-serine sodium salt (DMPS), 1,2-dimyristoyl-sn-glycero-3-phosphate monosodium salt (DMPA), nature phosphatidylserine sodium salt from brain and nature phosphatidylinositol sodium salt from soybean concentrations in liposomes. Liposomal fusion with intact bacteria was monitored using a lipid-mixing assay. Results It was discovered that the fluid liposomes-bacterium fusion is not dependent on liposomal size and lamellarity. A similar degree of fusion was observed for liposomes with a particle size from 100 to 800 nm. The fluidity of liposomes is an essential pre-request for liposomes fusion with bacteria. Fusion was almost completely inhibited by incorporation of cholesterol into fluid liposomes. The increase in the amount of negative charges in fluid liposomes reduces fluid liposomes-bacteria fusion when tested without calcium cations due to electric repulsion, but addition of calcium cations brings the fusion level of fluid liposomes to similar or higher levels. Among the negative phospholipids examined, DMPA gave the highest degree of fusion, DMPS and DMPG had intermediate fusion levels, and PI resulted in the lowest degree of fusion. Furthermore, the fluid liposomal encapsulated tobramycin was prepared, and the bactericidal effect occurred more quickly when bacteria were cultured with liposomal encapsulated tobramycin. Conclusion The bactericidal potency of fluid liposomes is dramatically enhanced with respect to fusion ability when the fusogenic lipid, DOPE, is included. Regardless of changes in liposome composition, fluid liposomes-bacterium fusion is universally enhanced by calcium ions. The information obtained in this study will increase our understanding of fluid liposomal action mechanisms, and help in optimizing the new generation of fluid liposomal formulations for the treatment of pulmonary bacterial infections. PMID:23847417

Physicochemical characterization and study of in vitro interactions of pH-sensitive liposomes with the complement system.

PubMed

Carmo, Vildete A S; De Oliveira, Mônica C; Reis, Eduardo C O; Guimarães, Tânia M P D; Vilela, José M C; Andrade, Margareth S; Michalick, Marilene S M; Cardoso, Valbert N

2008-01-01

Complement activation is an important step in the acceleration of liposome clearance. The anaphylatoxins released following complement activation may motivate a wide variety of physiologic changes. We performed physicochemical characterization and in vitro studies of the interaction of complement system with both noncirculating and long-circulating pH-sensitive and nonpH-sensitive liposomes. The liposomes were characterized by diameter, zeta potential, and atomic force microscopy (AFM). The study of liposome interactions with complement system was conducted using hemolytic assay in rat serum. All liposomes presented a similar mean diameter (between 99.8 and 124.3 nm). The zeta potential was negative in all liposome preparations, except in liposomes modified with aminopoly (ethyleneglycol) 2000-distearoylphosphatidylethanolamine (aPEG(2000)-DSPE), which presented positive zeta potential. Atomic force microscopy images showed that non-long-circulating pH-sensitive liposomes are prone to vesicles aggregation. Non-pH-sensitive liposomes complement system activates, while pH-sensitive liposomes showed to be poor complement activators in rat serum.

Evaluation of the protective effects of curcuminoid (curcumin and bisdemethoxycurcumin)-loaded liposomes against bone turnover in a cell-based model of osteoarthritis.

PubMed

Yeh, Chih-Chang; Su, Yu-Han; Lin, Yu-Jhe; Chen, Pin-Jyun; Shi, Chung-Sheng; Chen, Cheng-Nan; Chang, Hsin-I

2015-01-01

Curcumin (Cur) and bisdemethoxycurcumin (BDMC), extracted from Curcuma longa, are poorly water-soluble polyphenol compounds that have shown anti-inflammatory potential for the treatment of osteoarthritis. To increase cellular uptake of Cur and BDMC in bone tissue, soybean phosphatidylcholines were used for liposome formulation. In this study, curcuminoid (Cur and BDMC)-loaded liposomes were characterized in terms of particle size, encapsulation efficiency, liposome stability, and cellular uptake. The results show that there is about 70% entrapment efficiency of Cur and BDMC in liposomes and that particle sizes are stable after liposome formation. Both types of liposome can inhibit macrophage inflammation and osteoclast differential activities. In comparison with free drugs (Cur and BDMC), curcuminoid-loaded liposomes were less cytotoxic and expressed high cellular uptake of the drugs. Of note is that Cur-loaded liposomes can prevent liposome-dependent inhibition of osteoblast differentiation and mineralization, but BDMC-loaded liposomes could not. With interleukin (IL)-1β stimulation, curcuminoid-loaded liposomes can successfully downregulate the expression of inflammatory markers on osteoblasts, and show a high osteoprotegerin (OPG)/receptor activator of nuclear factor κB ligand (RANKL) ratio to prevent osteoclastogenesis. In the present study, we demonstrated that Cur and BDMC can be successfully encapsulated in liposomes and can reduce osteoclast activity and maintain osteoblast functions. Therefore, curcuminoid-loaded liposomes may slow osteoarthritis progression.

Effect of the combinations between pea proteins and soluble fibres on cholesterolaemia and cholesterol metabolism in rats.

PubMed

Parolini, Cinzia; Manzini, Stefano; Busnelli, Marco; Rigamonti, Elena; Marchesi, Marta; Diani, Erika; Sirtori, Cesare R; Chiesa, Giulia

2013-10-01

Many functional foods and dietary supplements have been reported to be beneficial for the management of dyslipidaemia, one of the major risk factors for CVD. Soluble fibres and legume proteins are known to be a safe and practical approach for cholesterol reduction. The present study aimed at investigating the hypocholesterolaemic effect of the combinations of these bioactive vegetable ingredients and their possible effects on the expression of genes regulating cholesterol homeostasis. A total of six groups of twelve rats each were fed, for 28 d, Nath's hypercholesterolaemic diets, differing in protein and fibre sources, being, respectively, casein and cellulose (control), pea proteins and cellulose (pea), casein and oat fibres (oat), casein and apple pectin (pectin), pea proteins and oat fibres (pea+oat) and pea proteins and apple pectin (pea+pectin). Administration of each vegetable-containing diet was associated with lower total cholesterol concentrations compared with the control. The combinations (pea+oat and pea+pectin) were more efficacious than fibres alone in modulating cholesterolaemia ( - 53 and - 54%, respectively, at 28 d; P< 0·005). In rats fed the diets containing oat fibres or apple pectin, alone or in combination with pea proteins, a lower hepatic cholesterol content (P< 0·005) and higher hepatic mRNA concentrations of CYP7A1 and NTCP were found when compared with the control rats (P< 0·05). In summary, the dietary combinations of pea proteins and oat fibres or apple pectin are extremely effective in lowering plasma cholesterol concentrations in rats and affect cellular cholesterol homeostasis by up-regulating genes involved in hepatic cholesterol turnover.

Interactive effects of protein and carbohydrates on production of microbial metabolites in the large intestine of growing pigs.

PubMed

Taciak, Marcin; Barszcz, Marcin; Święch, Ewa; Tuśnio, Anna; Bachanek, Ilona

2017-06-01

The study aimed at determining the effect of protein type and indigestible carbohydrates on the concentration of microbial metabolites in the large intestine of pigs. The experiment involved 36 pigs (15 kg initial body weight) divided into six groups, fed cereal-based diets with highly digestible casein (CAS) or potato protein concentrate (PPC) of lower ileal digestibility. Each diet was supplemented with cellulose, raw potato starch or pectin. After 2 weeks of feeding, pigs were sacrificed and samples of caecal and ascending, transverse and descending colon digesta were collected for analyses of microbial metabolites. PPC increased the concentration of ammonia, p-cresol, indole, n-butyrate, isovalerate and most of the amines in comparison with CAS. Pectin reduced the production of p-cresol, indole, phenylethylamine and isovalerate in the large intestine compared with potato starch. Starch and pectin increased mainly the concentration of n-butyrate and n-valerate in the colon compared to cellulose. Interaction affected mainly amines. Feeding PPC diet with potato starch considerably increased putrescine, cadaverine, tyramine and total amines concentrations compared with PPC diets with pectin and cellulose, whereas feeding CAS diet with starch reduced their concentrations. There was also a significant effect of interaction between diet and intestinal segment on microbial metabolites. In conclusion, PPC intensifies proteolysis in the large intestine and also n-butyrate production. Raw starch and pectin similarly increase n-butyrate concentration but pectin inhibits proteolysis more efficiently than starch. The interactive effects of both factors indicate that pectin and cellulose may beneficially affect fermentative processes in case of greater protein flow to the large intestine.

Three Pectin Methylesterase Inhibitors Protect Cell Wall Integrity for Arabidopsis Immunity to Botrytis1

PubMed Central

Fabri, Eleonora; Willats, William G.T.

2017-01-01

Infection by necrotrophs is a complex process that starts with the breakdown of the cell wall (CW) matrix initiated by CW-degrading enzymes and results in an extensive tissue maceration. Plants exploit induced defense mechanisms based on biochemical modification of the CW components to protect themselves from enzymatic degradation. The pectin matrix is the main CW target of Botrytis cinerea, and pectin methylesterification status is strongly altered in response to infection. The methylesterification of pectin is controlled mainly by pectin methylesterases (PMEs), whose activity is posttranscriptionally regulated by endogenous protein inhibitors (PMEIs). Here, AtPMEI10, AtPMEI11, and AtPMEI12 are identified as functional PMEIs induced in Arabidopsis (Arabidopsis thaliana) during B. cinerea infection. AtPMEI expression is strictly regulated by jasmonic acid and ethylene signaling, while only AtPMEI11 expression is controlled by PME-related damage-associated molecular patterns, such as oligogalacturonides and methanol. The decrease of pectin methylesterification during infection is higher and the immunity to B. cinerea is compromised in pmei10, pmei11, and pmei12 mutants with respect to the control plants. A higher stimulation of the fungal oxalic acid biosynthetic pathway also can contribute to the higher susceptibility of pmei mutants. The lack of PMEI expression does not affect hemicellulose strengthening, callose deposition, and the synthesis of structural defense proteins, proposed as CW-remodeling mechanisms exploited by Arabidopsis to resist CW degradation upon B. cinerea infection. We show that PME activity and pectin methylesterification are dynamically modulated by PMEIs during B. cinerea infection. Our findings point to AtPMEI10, AtPMEI11, and AtPMEI12 as mediators of CW integrity maintenance in plant immunity. PMID:28082716

Claviceps purpurea expressing polygalacturonases escaping PGIP inhibition fully infects PvPGIP2 wheat transgenic plants but its infection is delayed in wheat transgenic plants with increased level of pectin methyl esterification.

PubMed

Volpi, Chiara; Raiola, Alessandro; Janni, Michela; Gordon, Anna; O'Sullivan, Donal M; Favaron, Francesco; D'Ovidio, Renato

2013-12-01

Claviceps purpurea is a biotrophic fungal pathogen of grasses causing the ergot disease. The infection process of C. purpurea on rye flowers is accompanied by pectin degradation and polygalacturonase (PG) activity represents a pathogenicity factor. Wheat is also infected by C. purpurea and we tested whether the presence of polygalacturonase inhibiting protein (PGIP) can affect pathogen infection and ergot disease development. Wheat transgenic plants expressing the bean PvPGIP2 did not show a clear reduction of disease symptoms when infected with C. purpurea. To ascertain the possible cause underlying this lack of improved resistance of PvPGIP2 plants, we expressed both polygalacturonases present in the C. purpurea genome, cppg1 and cppg2 in Pichia pastoris. In vitro assays using the heterologous expressed PGs and PvPGIP2 showed that neither PG is inhibited by this inhibitor. To further investigate the role of PG in the C. purpurea/wheat system, we demonstrated that the activity of both PGs of C. purpurea is reduced on highly methyl esterified pectin. Finally, we showed that this reduction in PG activity is relevant in planta, by inoculating with C. purpurea transgenic wheat plants overexpressing a pectin methyl esterase inhibitor (PMEI) and showing a high degree of pectin methyl esterification. We observed reduced disease symptoms in the transgenic line compared with null controls. Together, these results highlight the importance of pectin degradation for ergot disease development in wheat and sustain the notion that inhibition of pectin degradation may represent a possible route to control of ergot in cereals. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Correlation between the distribution of lignin and pectin and distribution of sorbed metal ions (lead and zinc) on coir (Cocos nucifera L.).

PubMed

Conrad, Kathrine

2008-11-01

Plant fibres are capacious for sorption of metal ions, and can be used in water cleaning. Knowledge about the sorption will help in selection of the fibre and optimisation of its chemical modification, if any. The aim of this paper is to investigate the connection, if any, between the distribution of lignin and pectin and the loading of Pb and Zn on coir (mesocarp fibres from Cocos nucifera L.). The coir consisted mainly of xylem and a fibre sheath. The lignin was evenly distributed in the cell walls of the fibre sheath, but in the xylem, there was no detectable content in the compound middle lamella, and a smaller content of lignin in the secondary walls than in the walls of the fibre sheath. The only detectable content of pectin in the fibre sheath walls was in the middle lamella, cell corners and extracellular matrix, while in the xylem, the pectin was almost evenly distributed in the wall, with a higher concentration in the middle lamella and cell corners. All cell walls facing the lacuna had a high content of pectin. The metal ions were mainly loaded on the xylem and cell walls facing the lacuna, maybe with an additional trend to be loaded on the large fibres. Lead was distributed on and across the whole secondary wall. Zinc was loaded on the secondary walls, but there was no information about the distribution across the wall. If there is a simple correlation between the loading of metal ions and the distribution of lignin or pectin, these investigations point at no correlation with lignin and a positive correlation with pectin. It has to be stressed that these conclusions are made on limited material and are therefore preliminary in nature.

Synthesis and in vitro characterization of entirely S-protected thiolated pectin for drug delivery.

PubMed

Hintzen, Fabian; Hauptstein, Sabine; Perera, Glen; Bernkop-Schnürch, Andreas

2013-11-01

The study was aimed to synthesize a thiolated polymer (thiomer) that is resistant to oxidation in solutions above pH 5. In order to protect a pectin-cysteine conjugate against premature oxidation, the thiomer was S-protected by a disulfide connected leaving group. Therefore, 2-mercaptonicotinic acid was first coupled to L-cysteine by a disulfide exchange reaction and the purified product was subsequently attached to pectin by a carbodiimide mediated amid bond formation. The obtained fully S-protected thiolated pectin was in vitro characterized with respect to co- and mucoadhesive properties and stability toward oxidation. The results indicated a 1.8-fold and 2.3-fold enhanced disintegration time at pH 6.8 of the S-protected thiolated pectin (Pec-Cys-MNA) compared to thiolated pectin (Pec-Cys) and unmodified pectin (Pec). Moreover, rheological measurements of polymer/mucus mixtures showed a 1.6-fold (compared to Pec-Cys) and 6.7-fold (compared to Pec) increased dynamic viscosity of Pec-Cys-MNA. On the other hand, in the presence of a strong oxidizing agent such as H2O2 (0.3% v/v), no increase in viscosity of Pec-Cys-MNA could be observed. A 6-month experiment also demonstrated the long-term stability of a liquid formulation based on Pec-Cys-MNA. Further investigations proved that the first time all thiol groups on a thiolated polymer could be protected owing to the novel synthesis. Accordingly, these features may help to develop thiomer based liquid or gel formulations targeting mucosal surfaces such as nasal, ocular or vaginal drug delivery systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Intron retention regulates the expression of pectin methyl esterase inhibitor (Pmei) genes during wheat growth and development.

PubMed

Rocchi, V; Janni, M; Bellincampi, D; Giardina, T; D'Ovidio, R

2012-03-01

Pectin is an important component of the plant cell wall and its remodelling occurs during normal plant growth or following stress responses. Pectin is secreted into the cell wall in a highly methyl-esterified form and subsequently de-methyl-esterified by pectin methyl esterase (PME), whose activity is controlled by the pectin methyl esterase inhibitor protein (PMEI). Cereal cell wall contains a low amount of pectin; nonetheless the level and pattern of pectin methyl esterification play a primary role during development or pathogen infection. Since few data are available on the role of PMEI in plant development and defence of cereal species, we isolated and characterised three Pmei genes (Tdpmei2.1, Tdpmei2.2 and Tdpmei3) and their encoded products in wheat. Sequence comparisons showed a low level of intra- and inter-specific sequence conservation of PMEIs. Tdpmei2.1 and Tdpmei2.2 share 94% identity at protein level, but only 20% identity with the product of Tdpmei3. All three Tdpmei genes code for functional inhibitors of plant PMEs and do not inhibit microbial PMEs or a plant invertase. RT-PCR analyses demonstrated, for the first time to our knowledge, that Pmei genes are regulated by intron retention. Processed and unprocessed transcripts of Tdpmei2.1 and Tdpmei2.2 accumulated in several organs, but anthers contained only mature transcripts. Tdpmei3 lacks introns and its transcript accumulated mainly in stem internodes. These findings suggest that products encoded by these Tdpmei genes control organ- or tissue-specific activity of specific PME isoforms in wheat. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

[Cocoa (Theobroma cacao L.) hulls: a posible commercial source of pectins].

PubMed

Barazarte, Humberto; Sangronis, Elba; Unai, Emaldi

2008-03-01

Commercial exploitation of cocoa (Theobroma cacao L.) generates a volume of hulls that could be used in the production of pectins on an industrial scale. Therefore, pectins from cocoa hulls were extracted at different pH and temperature conditions, and their main chemical characteristics were evaluated. EDTA at 0.5% was used for the extraction at pHs 3, 4 and 5 and temperatures of 60, 75 and 90 degrees C, under a 3 2 factorial design. The response variables were yield, content of anhydrous galacturonic acid (AGA), content of metoxil, degree of esterification and equivalent weight of the pectins extracted. The strength of the pectic gel was determined with a TA-XT2 texturometer. Strawberry jam was made with the pectin extracted, and its acceptability was determined using a 7-point hedonic scale. The results obtained were as follows: an extraction yield from 2.64 to 4.69 g/100 g; an AGA content between 49.8 and 64.06 g/100 g; a content of metoxil between 4.72 and 7.18 g/100 g; a degree of esterification between 37.94 and 52.20%; an equivalent weight from 385.47 to 464.61 g/equivalent of H+, and a degree of gelation between 28.64 and 806.03 g force. The pectin extracted at pH 4 and 90 degrees C showed a gelation power of 422.16 g force, purity 62.26 g/100 g of AGA, and a yield of extraction of 3.89 g/100 g and allowed to prepare ajam with an average level of liking of "like moderately". Pectins from cocoa hulls show potential application in the food industry, but it is necessary to optimize the extraction parameters to increase its yield.

Pectins, Hemicelluloses and Celluloses Show Specific Dynamics in the Internal and External Surfaces of Grape Berry Skin During Ripening.

PubMed

Fasoli, Marianna; Dell'Anna, Rossana; Dal Santo, Silvia; Balestrini, Raffaella; Sanson, Andrea; Pezzotti, Mario; Monti, Francesca; Zenoni, Sara

2016-06-01

Grapevine berry skin is a complex structure that contributes to the final size and shape of the fruit and affects its quality traits. The organization of cell wall polysaccharides in situ and their modification during ripening are largely uncharacterized. The polymer structure of Corvina berry skin, its evolution during ripening and related modifying genes were determined by combing mid-infrared micro-spectroscopy and multivariate statistical analysis with transcript profiling and immunohistochemistry. Spectra were acquired in situ using a surface-sensitive technique on internal and external sides of the skin without previous sample pre-treatment, allowing comparison of the related cell wall polymer dynamics. The external surface featured cuticle-related bands; the internal surface showed more adsorbed water. Application of surface-specific normalization revealed the major molecular changes related to hemicelluloses and pectins in the internal surface and to cellulose and pectins in the external surface and that they occur between mid-ripening and full ripening in both sides of the skin. Transcript profiling of cell wall-modifying genes indicated a general suppression of cell wall metabolism during ripening. Genes related to pectin metabolism-a β-galactosidase, a pectin(methyl)esterase and a pectate lyase-and a xyloglucan endotransglucosylase/hydrolase, involved in hemicellulose modification, showed enhanced expression. In agreement with Fourier transform infrared spectroscopy, patterns due to pectin methyl esterification provided new insights into the relationship between pectin modifications and the associated transcript profile during skin ripening. This study proposes an original description of polymer dynamics in grape berries during ripening, highlighting differences between the internal and external sides of the skin. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Cell Wall Pectin and its Methyl-esterification in Transition Zone Determine Al Resistance in Cultivars of Pea (Pisum sativum)

PubMed Central

Li, Xuewen; Li, Yalin; Qu, Mei; Xiao, Hongdong; Feng, Yingming; Liu, Jiayou; Wu, Lishu; Yu, Min

2016-01-01

The initial response of plants to aluminum (Al) is the inhibition of root elongation, while the transition zone is the most Al sensitive zone in the root apex, which may sense the presence of Al and regulate the responses of root to Al toxicity. In the present study, the effect of Al treatment (30 μM, 24 h) on root growth, Al accumulation, and properties of cell wall of two pea (Pisum sativum L.) cultivars, cv Onward (Al-resistant) and cv Sima (Al-sensitive), were studied to disclose whether the response of root transition zone to Al toxicity determines Al resistance in pea cultivars. The lower relative root elongation (RRE) and higher Al content were founded in cv Sima compared with cv Onward, which were related to Al-induced the increase of pectin in root segments of both cultivars. The increase of pectin is more prominent in Al-sensitive cultivar than in Al-resistant cultivar. Aluminum toxicity also induced the increase of pectin methylesterases (PME), which is 2.2 times in root transition zone in Al-sensitive cv Sima to that of Al resistant cv Onward, thus led to higher demethylesterified pectin content in root transition zone of Al-sensitive cv Sima. The higher demethylesterified pectin content in root transition zone resulted in more Al accumulation in the cell wall and cytosol in Al-sensitive cv Sima. Our results provide evidence that the increase of pectin content and PME activity under Al toxicity cooperates to determine Al sensitivity in root transition zone that confers Al resistance in cultivars of pea (Pisum sativum). PMID:26870060

[Infrared spectroscopic study on the component and vigor analysis of Cistanche deserticola seeds].

PubMed

Xu, Rong; Sun, Su-Qin; Chen, Jun; Chen, Shi-Lin; Zhou, Feng

2009-01-01

Comparative study of the different parts of cistanche deserticola seeds and their changes after different processing were examined by Fourier transform infrared spectroscopy spectra (FTIR). The results of the analysis showed that components in the cistanche deserticola seeds were abundant, which contained characteristic absorption peaks of protein, fat and carbohydrate. As well, pectin and aromatic compound can be also found in the seeds. However, the components were different in different parts of cistanche deserticola seeds. The characteristic absorption peak intensities of fat at 2,926, 1,746, 1,161 and 721 cm(-1) were the strongest in the seed kernels. However, the seed coats mainly consisted of carbohydrate and pectin, which were showed at 1,054 cm(-1). The contents of protein and carbohydrate were decreased distinctly in the moldy and dead seeds after processing. The characteristic absorption peak intensity ratio of protein to fat (I1,630/I1,745 ) was all higher than 1.05 in the live seeds. The characteristic absorption peak intensity ratio of amido link I of protein to fat (11,653/I1,745) in the dead seed kernels of the cistanche deserticola was decreased from 0.31 to 0. 23, which was 25.8% less than that in vital seed kernels. The results suggest that FTIR not only can be used in fast comprehensive analysis of seed components, but also can be used in the seed vigor analysis, seed longevity determination and seed quality evaluation.

Rice putative methyltransferase gene OsTSD2 is required for root development involving pectin modification.

PubMed

Qu, Lianghuan; Wu, Chunyan; Zhang, Fei; Wu, Yangyang; Fang, Chuanying; Jin, Cheng; Liu, Xianqing; Luo, Jie

2016-10-01

Pectin synthesis and modification are vital for plant development, although the underlying mechanisms are still not well understood. Here, we report the functional characterization of the OsTSD2 gene, which encodes a putative methyltransferase in rice. All three independent T-DNA insertion lines of OsTSD2 displayed dwarf phenotypes and serial alterations in different zones of the root. These alterations included abnormal cellular adhesion and schizogenous aerenchyma formation in the meristematic zone, inhibited root elongation in the elongation zone, and higher lateral root density in the mature zone. Immunofluorescence (with LM19) and Ruthenium Red staining of the roots showed that unesterified homogalacturonan (HG) was increased in Ostsd2 mutants. Biochemical analysis of cell wall pectin polysaccharides revealed that both the monosaccharide composition and the uronic acid content were decreased in Ostsd2 mutants. Increased endogenous ABA content and opposite roles performed by ABA and IAA in regulating cellular adhesion in the Ostsd2 mutants suggested that OsTSD2 is required for root development in rice through a pathway involving pectin synthesis/modification. A hypothesis to explain the relationship among OsTSD2, pectin methylesterification, and root development is proposed, based on pectin's function in regional cell extension/division in a zone-dependent manner. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Preparation and biocompatibility evaluation of pectin and chitosan cryogels for biomedical application.

PubMed

Konovalova, Mariya V; Markov, Pavel A; Durnev, Eugene A; Kurek, Denis V; Popov, Sergey V; Varlamov, Valery P

2017-02-01

Today, there is a need for the development of biomaterials with novel properties for biomedical purposes. The biocompatibility of materials is a key factor in determining its possible use in biomedicine. In this study, composite cryogels were obtained based on pectin and chitosan using ionic cryotropic gelation. For cryogel preparation, apple pectin (AP), Heracleum L. pectin (HP), and chitosan samples with different physical and chemical characteristics were used. The properties of pectin-chitosan cryogels were found to depend on the structural features and physicochemical characteristics of the pectin and chitosan within them. The addition of chitosan to cryogels can increase their mechanical strength, cause change in surface morphology, increase the degradation time, and enhance adhesion to biological tissues. Cryogels based on AP were less immunogenic when compared with cryogels from HP. Cryogels based on AP and HP were hemocompatible and the percentage of red blood cells hemolysis was less than 5%. Unlike cryogels based on HP, which exhibited moderate cytotoxicity, cryogels based on AP exhibited light cytotoxicity. Based on the results of low immunogenicity, light cytotoxicity data as well as a low level of hemolysis of composite cryogels based on AP and chitosan are biocompatible and can potentially be used in biomedicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 547-556, 2017. © 2016 Wiley Periodicals, Inc.

Characterization of Pectins Extracted from Different Varieties of Pink/Red and White Grapefruits [Citrus Paradisi (Macf.)] by Thermal Treatment and Thermosonication.

PubMed

La Cava, Enzo L; Gerbino, Esteban; Sgroppo, Sonia C; Gómez-Zavaglia, Andrea

2018-06-01

The physical and chemical properties of pectin extracts obtained from different white and pink/red varieties of grapefruit [Citrus paradisi (Macf.)], using both conventional heating (CHE) and thermosonication (TS), were investigated. The content of galacturonic acid (GalA), degree of esterification (%DM), color and antioxidant capacity were analyzed. Fourier-Transform Infrared Spectroscopy (FTIR) associated with multivariate analysis enabled a structural comparison among the pectin extracts, and differential scanning calorimetry (DSC) completed a full landscape of the investigated extracts. Pectin extracts obtained by CHE showed mostly higher GalA than those obtained by TS. All the extracts had a high antioxidant capacity, as determined by 2,2 diphenyl 1-picrylhydrazyl (DPPH * ) and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS * +) assays, and a high correlation with the GalA content. The main differences observed in the FTIR spectra occurred in the 1200 to 900 cm -1 region (differences in GalA). The glass transition temperatures (Tgs) of all extracts were above 85 °C, making them interesting as stabilizing agents for the food industry. A wide database for the characterization of pectin extracts from grapefruits was obtained. The relationship between the extraction method and the source of pectins, with the physicochemical and antioxidant properties provided great support for their application in the food industry. © 2018 Institute of Food Technologists®.

Dynamic Changes of Pectin Epitopes in Cell Walls during the Development of the Procambium–Cambium Continuum in Poplar

PubMed Central

Liu, Jundi; Hou, Jie; Chen, Huimin; Pei, Keliang; Li, Yi; He, Xin-Qiang

2017-01-01

The change of pectin epitopes during procambium–cambium continuum development was investigated by immunolocalization in poplar. The monoclonal antibody JIM5 labels homogalacturonan (HGA) with a low degree of esterification, and the monoclonal antibody JIM7 labels HGA with a high degree of methyl-esterification. Arabinan, rather than galactan, and HGA with low degree of esterification were located in the cell walls of procambial, while HGA with a low degree of esterification was located in the tangential walls, and galactan was located in both the tangential and radial walls of procambial, yet nearly no arabinan was located in the tangential walls of the cambial cells. The changes in pectin distribution took place when periclinal divisions appeared within a procambial trace. The distribution difference of pectin epitopes was also present in procambium–cambium derivatives. The arabinan existed in all cell walls of primary xylem, but was absent from the tangential walls of secondary xylem cells. The galactan existed only in mature primary phloem. Furthermore, 19 pectin methylesterases (PMEs) genes were identified by RNA sequencing, six genes presented highly differentially and were supposed to be involved in the cell wall esterification process. The results provide direct evidence of the dynamic changes of pectin epitopes during the development of the procambium–cambium continuum in poplar. PMID:28783076

Requirement for pectin methyl esterase and preference for fragmented over native pectins for wall-associated kinase-activated, EDS1/PAD4-dependent stress response in Arabidopsis.

PubMed

Kohorn, Bruce D; Kohorn, Susan L; Saba, Nicholas J; Martinez, Victoriano Meco

2014-07-04

The wall-associated kinases (WAKs) have a cytoplasmic protein kinase domain that spans the plasma membrane and binds pectin in the extracellular matrix of plants. WAKs are required for cell expansion during Arabidopsis seedling development but are also an integral part of the response to pathogens and stress that present oligogalacturonides (OGs), which subsequently bind to WAKs and activate a MPK6 (mitogen-activated protein kinase)-dependent pathway. It was unclear how WAKs distinguish native pectin polymers and OGs to activate one or the other of these two pathways. A dominant allele of WAK2 constitutively activates the stress response, and we show here that the effect is dependent upon EDS1 and PAD4, transcriptional activators involved in the pathogen response. Moreover, the WAK2 dominant allele is suppressed by a null allele of a pectin methyl esterase (PME3) whose activity normally leads to cross-linking of pectins in the cell wall. Although OGs activate a transcriptional response in wild type, the response is enhanced in a pme3/pme3 null, consistent with a competition by OG and native polymers for activation of WAKs. This provides a plausible mechanism for WAKs to distinguish an expansion from a stress pathway. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Rice pectin methylesterase inhibitor28 (OsPMEI28) encodes a functional PMEI and its overexpression results in a dwarf phenotype through increased pectin methylesterification levels.

PubMed

Nguyen, Hong Phuong; Jeong, Ho Young; Jeon, Seung Ho; Kim, Donghyuk; Lee, Chanhui

2017-01-01

Pectin methylesterases (PMEs, EC 3.1.1.11) belonging to carbohydrate esterase family 8 cleave the ester bond between a galacturonic acid and an methyl group and the resulting change in methylesterification level plays an important role during the growth and development of plants. Optimal pectin methylesterification status in each cell type is determined by the balance between PME activity and post-translational PME inhibition by PME inhibitors (PMEIs). Rice contains 49 PMEIs and none of them are functionally characterized. Genomic sequence analysis led to the identification of rice PMEI28 (OsPMEI28). Recombinant OsPMEI28 exhibited inhibitory activity against commercial PME protein with the highest activities detected at pH 8.5. Overexpression of OsPMEI28 in rice resulted in an increased level of cell wall bound methylester groups and differential changes in the composition of cell wall neutral monosaccharides and lignin content in culm tissues. Consequently, transgenic plants overexpressing OsPMEI28 exhibited dwarf phenotypes and reduced culm diameter. Our data indicate that OsPMEI28 functions as a critical structural modulator by regulating the degree of pectin methylesterification and that an impaired status of pectin methylesterification affects physiochemical properties of the cell wall components and causes abnormal cell extensibility in rice culm tissues. Copyright © 2016 Elsevier GmbH. All rights reserved.

High-throughput screening of Erwinia chrysanthemi pectin methylesterase variants using carbohydrate microarrays.

PubMed

Øbro, Jens; Sørensen, Iben; Derkx, Patrick; Madsen, Christian T; Drews, Martin; Willer, Martin; Mikkelsen, Jørn D; Willats, William G T

2009-04-01

Pectin methylesterases (PMEs) catalyse the removal of methyl esters from the homogalacturonan (HG) backbone domain of pectin, a ubiquitous polysaccharide in plant cell walls. The degree of methyl esterification (DE) impacts upon the functional properties of HG within cell walls and plants produce numerous PMEs that act upon HG in muro. Many microbial plant pathogens also produce PMEs, the activity of which renders HG more susceptible to cleavage by pectin lyase and polygalacturonase enzymes and hence aids cell wall degradation. We have developed a novel microarray-based approach to investigate the activity of a series of variant enzymes based on the PME from the important pathogen Erwinia chrysanthemi. A library of 99 E. chrysanthemi PME mutants was created in which seven amino acids were altered by various different substitutions. Each mutant PME was incubated with a highly methyl esterified lime pectin substrate and, after digestion the enzyme/substrate mixtures were printed as microarrays. The loss of activity that resulted from certain mutations was detected by probing arrays with a mAb (JIM7) that preferentially binds to HG with a relatively high DE. Active PMEs therefore resulted in diminished JIM7 binding to the lime pectin substrate, whereas inactive PMEs did not. Our findings demonstrate the feasibility of our approach for rapidly testing the effects on PME activity of substituting a wide variety of amino acids at different positions.

Formation and rupture of Ca(2+) induced pectin biopolymer gels.

PubMed

Basak, Rajib; Bandyopadhyay, Ranjini

2014-10-07

When calcium salts are added to an aqueous solution of polysaccharide pectin, ionic cross-links form between pectin chains, giving rise to a gel network in dilute solution. In this work, dynamic light scattering (DLS) is employed to study the microscopic dynamics of the fractal aggregates (flocs) that constitute the gels, while rheological measurements are carried out to study the process of gel rupture. As the calcium salt concentration is increased, DLS experiments reveal that the polydispersity of the flocs increase simultaneously with the characteristic relaxation times of the gel network. Above a critical salt concentration, the flocs become interlinked to form a reaction-limited fractal gel network. Rheological studies demonstrate that the limits of the linear rheological response and the critical stresses required to rupture these networks both decrease with the increase in salt concentration. These features indicate that the ion-mediated pectin gels studied here lie in a 'strong link' regime that is characterised by inter-floc links that are stronger than intra-floc links. A scaling analysis of the experimental data presented here demonstrates that the elasticities of the individual fractal flocs exhibit power-law dependences on the added salt concentration. We conclude that when both pectin and salt concentrations are increased, the number of fractal flocs of pectin increases simultaneously with the density of crosslinks, giving rise to very large values of the bulk elastic modulus.

Polysaccharide-based hydrogels with tunable composition as 3D cell culture systems.

PubMed

Gentilini, Roberta; Munarin, Fabiola; Bloise, Nora; Secchi, Eleonora; Visai, Livia; Tanzi, Maria Cristina; Petrini, Paola

2018-04-01

To date, cell cultures have been created either on 2-dimensional (2D) polystyrene surfaces or in 3-dimensional (3D) systems, which do not offer a controlled chemical composition, and which lack the soft environment encountered in vivo and the chemical stimuli that promote cell proliferation and allow complex cellular behavior. In this study, pectin-based hydrogels were developed and are proposed as versatile cell culture systems. Pectin-based hydrogels were produced by internally crosslinking pectin with calcium carbonate at different initial pH, aiming to control crosslinking kinetics and degree. Additionally, glucose and glutamine were added as additives, and their effects on the viscoelastic properties of the hydrogels and on cell viability were investigated. Pectin hydrogels showed in high cell viability and shear-thinning behavior. Independently of hydrogel composition, an initial swelling was observed, followed by a low percentage of weight variation and a steady-state stage. The addition of glucose and glutamine to pectin-based hydrogels rendered higher cell viability up to 90%-98% after 1 hour of incubation, and these hydrogels were maintained for up to 7 days of culture, yet no effect on viscoelastic properties was detected. Pectin-based hydrogels that offer tunable composition were developed successfully. They are envisioned as synthetic extracellular matrix (ECM) either to study complex cellular behaviors or to be applied as tissue engineering substitutes.

Emulsions of sunflower wax in pectin aqueous solutions: Physical characterization and stability.

PubMed

Chalapud, Mayra C; Baümler, Erica R; Carelli, Amalia A

2018-06-01

The knowledge of the stability and physical properties of film-forming solutions is necessary for optimizing the process design of films. In order to evaluate their applicability for the production of edible films, the rheological and microstructural properties, particle size and physicochemical stability of aqueous emulsions of low methoxyl pectin and sunflower waxes from normal and high-oleic hybrids were assessed. Emulsions were prepared with different pectin concentrations (1, 2 and 3% w/w) and wax proportions (0.1, 0.2 and 0.3 g/g pectin). The rheological behavior was best described by the power law model. The values of the behavior index (n) were close to 1, exhibiting a behavior close to Newtonian fluids. The addition of waxes caused an increase in viscosity and shear stress. The particle size of the emulsions made with waxes from high-oleic sunflower was smaller than those from the normal hybrid. In most cases, size distributions with greater height and less amplitude were obtained, mainly when the pectin content was higher. Confocal images allowed to observe the presence of waxes and their dispersion in the pectin matrix. Destabilization phenomena such as sedimentation, coalescence and creaming were observed at long test times independent of the wax origin. These results evidence the potential use of these emulsions for the manufacture of edible films. Copyright © 2018 Elsevier Ltd. All rights reserved.

The role of surface charge density in cationic liposome-promoted dendritic cell maturation and vaccine-induced immune responses

NASA Astrophysics Data System (ADS)

Ma, Yifan; Zhuang, Yan; Xie, Xiaofang; Wang, Ce; Wang, Fei; Zhou, Dongmei; Zeng, Jianqiang; Cai, Lintao

2011-05-01

Cationic liposomes have emerged as a novel adjuvant and antigen delivery system to enhance vaccine efficacy. However, the role of surface charge density in cationic liposome-regulated immune responses has not yet been elucidated. In the present study, we prepared a series of DOTAP/DOPC cationic liposomes with different surface densities by incorporating varying amounts of DOPC (a neutral lipid) into DOTAP (a cationic lipid). The results showed that DOTAP/DOPC cationic liposome-regulated immune responses relied on the surface charge density, and might occur through ROS signaling. The liposomes with a relatively high charge density, such as DOTAP/DOPC 5 : 0 and 4 : 1 liposomes, potently enhanced dendritic cell maturation, ROS generaion, antigen uptake, as well as the production of OVA-specific IgG2a and IFN-γ. In contrast, low-charge liposomes, such as DOTAP/DOPC 1 : 4 liposome, failed to promote immune responses even at high concentrations, confirming that the immunoregulatory effect of cationic liposomes is mostly attributable to their surface charge density. Moreover, the DOTAP/DOPC 1 : 4 liposome suppressed anti-OVA antibody responses in vivo. Overall, maintaining an appropriate surface charge is crucial for optimizing the adjuvant effect of cationic liposomes and enhancing the efficacy of liposome-based vaccines.

Curcumin liposomes prepared with milk fat globule membrane phospholipids and soybean lecithin.

PubMed

Jin, Hong-Hao; Lu, Qun; Jiang, Jian-Guo

2016-03-01

Using thin film ultrasonic dispersion method, the curcumin liposomes were prepared with milk fat globule membrane (MFGM) phospholipids and soybean lecithins, respectively, to compare the characteristics and stability of the 2 curcumin liposomes. The processing parameters of curcumin liposomes were investigated to evaluate their effects on the encapsulation efficiency. Curcumin liposomes were characterized in terms of size distribution, ζ-potential, and in vitro release behavior, and then their storage stability under various conditions was evaluated. The curcumin liposomes prepared with MFGM phospholipids had an encapsulation efficiency of about 74%, an average particle size of 212.3 nm, and a ζ-potential of -48.60 mV. The MFGM liposomes showed higher encapsulation efficiency, smaller particle size, higher absolute value of ζ-potential, and slower in vitro release than soybean liposomes. The retention rate of liposomal curcumin was significantly higher than that of free curcumin. The stability of the 2 liposomes under different pH was almost the same, but MFGM liposomes displayed a slightly higher stability than soybean liposomes under the conditions of Fe(3+), light, temperature, oxygen, and relative humidity. In conclusion, MFGM phospholipids have potential advantages in the manufacture of curcumin liposomes used in food systems. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

In vitro and in vivo evaluation of novel NGR-modified liposomes containing brucine.

PubMed

Li, Shu; Wang, Xi-Peng

2017-01-01

In this study, a novel NGR (Asn-Gly-Arg) peptide-modified liposomal brucine was prepared by using spray-drying method. The surface morphology of the liposomes, encapsulation efficiency and particle size were investigated. The data showed that the addition of NGR did not produce any significant influence on brucine liposomes in terms of particle size or zeta potential. In addition, after 3 months of storage, no dramatic change such as visible aggregation, drug content changes or precipitation in the appearance of NGR-brucine liposomes occurred. The in vitro release results indicated that the release of brucine from NGR liposomes was similar to that of liposomes, demonstrating that the NGR modification did not affect brucine release. The in vitro drug-release kinetic model of NGR-brucine liposomes fitted well with the Weibull's equation. In vivo, NGR-brucine liposomes could significantly extend the bioavailability of brucine; however, there was no significant difference observed in the pharmacokinetic parameters between liposomes and NGR liposomes after intravenous administration. Antitumor activity results showed that NGR-modified liposomes exhibited less toxicity and much higher efficacy in HepG2-bearing mice compared with non-modified liposomes. The enhanced antitumor activity might have occurred because brucine was specifically recognized by NGR receptor on the surface of tumor cells, which enhanced the intracellular uptake of drugs.

Antileishmanial Activity of Liposomal Clarithromycin against Leishmania Major Promastigotes.

PubMed

Sazgarnia, Ameneh; Zabolinejad, Naghmeh; Layegh, Pouran; Rajabi, Omid; Berenji, Fariba; Javidi, Zari; Salari, Roshanak

2012-11-01

Cutaneous leishmaniasis is a common parasitic disease which is endemic in some parts of the world. In vitro and in vivo studies have shown azithromycin efficacy on some Leishmania species. Because of structural similarity between clarithromycin and azithromycin and efficacy of clarithromycin against intracellular organisms and due to the absence of previous studies in this respect, we decided to evaluate the efficacy of clarithromycin against promastigotes of L. major in vitro. First, liposomal and non- liposomal clarithromycin were prepared, then both forms of the drug were incubated with promastigotes for 24 hr in NNN culture media without red phenol in the presence of 5% FCS with different concentrations as follows: 20, 40, 80, 100, 200 and 500 µg/ml. According to the results, clarithromycin in both liposomal and non- liposomal forms has in vitro activity against the promastigotes of L. major. The concentration of drug that killed 50% of parasites (ED 50) was 169 and 253.6 µg/ml for liposomal and non- liposomal forms, respectively which shows that lower concentrations of liposomal drug are required to have the same effect as non- liposomal drug and the liposomal form of the drug is more effective than non- liposomal form. Clarithromycin in both liposomal and non- liposomal forms has in vitro activity against the promastigotes of L. major.

Pharmaceutical liposomal drug delivery: a review of new delivery systems and a look at the regulatory landscape.

PubMed

Zylberberg, Claudia; Matosevic, Sandro

2016-11-01

Liposomes were the first nanoscale drug to be approved for clinical use in 1995. Since then, the technology has grown considerably, and pioneering recent work in liposome-based delivery systems has brought about remarkable developments with significant clinical implications. This includes long-circulating liposomes, stimuli-responsive liposomes, nebulized liposomes, elastic liposomes for topical, oral and transdermal delivery and covalent lipid-drug complexes for improved drug plasma membrane crossing and targeting to specific organelles. While the regulatory bodies' opinion on liposomes is well-documented, current guidance that address new delivery systems are not. This review describes, in depth, the current state-of-the-art of these new liposomal delivery systems and provides a critical overview of the current regulatory landscape surrounding commercialization efforts of higher-level complexity systems, the expected requirements and the hurdles faced by companies seeking to bring novel liposome-based systems for clinical use to market.

Intermolecular binding of blueberry pectin-rich fractions and anthocyanin.

PubMed

Lin, Z; Fischer, J; Wicker, L

2016-03-01

Pectin was extracted from blueberry powder into three fractions of water soluble (WSF), chelator soluble (CSF) and sodium carbonate soluble (NSF). The fractions were incubated with cyanidin-3-glucoside (C3G), a mixture of five anthocyanidins (cyanidin, pelargonidin, malvidin, petunidin and delphinidin) or blueberry juice at pH 2.0-4.5. Free anthocyanins and bound anthocyanin-pectin mixtures were separated by ultrafiltration. WSF bound the least amount of anthocyanin at all pH values. CSF had stronger anthocyanin binding ability at pH 2.0-3.6, while NSF had stronger anthocyanin binding ability at pH 3.6-4.5. The pectin and anthocyanin binding was lowest at pH 4.5 and higher at pH 2.0-3.6. Nearly doubling C3G pigment content increased bound anthocyanin percentage by 16-23% at pH 3.6, which favored anthocyanin aromatic stacking, compared to 3-9% increase at pH 2.0. Ionic interaction between anthocyanin flavylium cations and free pectic carboxyl groups, and anthocyanin stacking may be two major mechanisms for pectin and anthocyanin binding. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of pectin extraction from banana peels with citric acid by using response surface methodology.

PubMed

Oliveira, Túlio Ítalo S; Rosa, Morsyleide F; Cavalcante, Fabio Lima; Pereira, Paulo Henrique F; Moates, Graham K; Wellner, Nikolaus; Mazzetto, Selma E; Waldron, Keith W; Azeredo, Henriette M C

2016-05-01

A central composite design was used to determine effects of pH (2.0-4.5), extraction temperature (70-90 °C) and time (120-240 min) on the yield, degree of methoxylation (DM) and galacturonic acid content (GA) of pectins extracted from banana peels with citric acid. Changes in composition during the main steps of pectin extraction were followed by Fourier transform infrared (FTIR) spectroscopy. FTIR was also used to determine DM and GA of pectins. Harsh temperature and pH conditions enhanced the extraction yield, but decreased DM. GA presented a maximum value at 83 °C, 190 min, and pH 2.7. The yield of galacturonic acid (YGA), which took into account both the extraction yield and the pectin purity, was improved by higher temperature and lower pH values. The optimum extraction conditions, defined as those resulting in a maximum YGA while keeping DM at a minimum of 51%, were: 87 °C, 160 min, pH 2.0. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of continuous and intermittent microwave extraction of pectin from banana peels.

PubMed

Swamy, Gabriela John; Muthukumarappan, Kasiviswanathan

2017-04-01

Continuous and intermittent microwave-assisted extractions were used to extract pectin from banana peels. Extraction parameters which were employed in the continuous process were microwave power (300-900W), time (100-300s), pH (1-3) and in the intermittent process were microwave power (300-900W), pulse ratio (0.5-1), pH (1-3). The independent factors were optimized with the Box-Behnken response surface design (BBD) (three factor three level) with the desirability function methodology. Results indicate that the independent factors have substantial effect on the pectin yield. Optimized solutions for highest pectin yield (2.18%) from banana peels were obtained with microwave power of 900W, time 100s and pH 3.00 in the continuous method while the intermittent process yielded the highest pectin content (2.58%) at microwave power of 900W, pulse ratio of 0.5 and pH of 3.00. The optimized conditions were validated and close agreement was observed with the validation experiment and predicted value. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chitosan/pectin/gum Arabic polyelectrolyte complex: process-dependent appearance, microstructure analysis and its application.

PubMed

Tsai, Ruei-Yi; Chen, Pin-Wen; Kuo, Ting-Yun; Lin, Che-Min; Wang, Da-Ming; Hsien, Tzu-Yang; Hsieh, Hsyue-Jen

2014-01-30

Novel chitosan/pectin/gum Arabic polyelectrolyte complex (PEC) solutions and membranes with various compositions were prepared for biomedical applications. The appearance of the PEC solutions, either clear or turbid, was process-dependent and depended on how the three components were dissolved and mixed. The addition of gum Arabic to the chitosan and pectin significantly decreased the viscosities of the resultant PEC solutions due to the formation of globe-like microstructures that was accompanied by network-like microstructures and other molecular entanglements. The mechanical strength and hydrophilicity of the PEC membranes manufactured from the PEC solutions, especially for a weight ratio of 84/8/8 (chitosan/pectin/gum Arabic), were enhanced compared to pure chitosan membranes. Moreover, the use of the 84/8/8 PEC membranes as a drug carrier exhibited steady and fairly complete release of a drug (insulin) for 6h. Based on these promising results, the chitosan/pectin/gum Arabic PEC membranes have great potential in controlled drug release applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mode of de-esterification of alkaline and acidic pectin methyl esterases at different pH conditions.

PubMed

Duvetter, Thomas; Fraeye, Ilse; Sila, Daniel N; Verlent, Isabel; Smout, Chantal; Hendrickx, Marc; Van Loey, Ann

2006-10-04

Highly esterified citrus pectin was de-esterified at pH 4.5 and 8.0 by a fungal pectin methyl esterase (PME) that was shown to have an acidic isoelectric pH (pI) and an acidic pH optimum and by a plant PME that was characterized by an alkaline pI and an alkaline pH optimum. Interchain and intrachain de-esterification patterns were studied by digestion of the pectin products with endo-polygalacturonase and subsequent analysis using size exclusion and anion-exchange chromatography. No effect of pH was observed on the de-esterification mode of either of the two enzymes. Acidic, fungal PME converted pectin according to a multiple-chain mechanism, with a limited degree of multiple attack at the intrachain level, both at pH 4.5 and at pH 8.0. A multiple-attack mechanism, with a high degree of multiple attack, was more appropriate to describe the action mode of alkaline, plant PME, both at pH 4.5 and at pH 8.0.

Quality evaluation of banana skin extract jellies.

PubMed

Borges, S V; Valente, W A; Figueiredo, L P; Dias, M V; Pereira, P P; Pereira, A G T; Clemente, P R

2011-04-01

Due to the great volume of banana skin resulting from the industrialization of banana and to their high pectin content, the objectives of the present study were to evaluate the effect of the following factors: extract/sugar, pectin and citric acid on the chemical, physical and sensory qualities of the jellies obtained. A complete factorial experimental design was used (2(3)) with 3 central points to evaluate the influence of the factors on the dependent variables, testing the linear models. The chemical properties underwent few alterations and the instrumental and sensory texture attributes were mainly affected by the extract/sugar ratio and the pectin level. The brittleness, elasticity and gumminess increased with increases in the extract/ sugar ratio and pectin level. According to the sensory analysis and the purchasing intention, the best formulations were those obtained using a higher extract/sugar ratio (60/40) and lower pectin level (0.5 g/ 100), combined with the highest (20 mL) or lowest volumes of citric acid (15 mL), with scores for all the attributes in the range from 'I liked slightly' to 'I liked moderately'.

Pectins filled with LDH-antimicrobial molecules: preparation, characterization and physical properties.

PubMed

Gorrasi, Giuliana; Bugatti, Valeria; Vittoria, Vittoria

2012-06-05

Nanohybrids of layered double hydroxide (LDH) with intercalated active molecules: benzoate, 2,4-dichlorobenzoate, para-hydroxybenzoate and ortho-hydroxybenzoate, were incorporated into pectins from apples through high energy ball milling in the presence of water. Cast films were obtained and analysed. X-ray diffraction analysis showed a complete destructuration of all nanohybrids in the pectin matrix. Thermogravimetric analysis showed a better thermal resistance of pectin in the presence of fillers, especially para-hydroxybenzoate and ortho-hydroxybenzoate. Mechanical properties showed an improvement of elastic modulus in particular for LDH-para-hydroxybenzoate nanohybrid, due probably to a better interaction between pectin matrix and nanohybrid layers. Barrier properties (sorption and diffusion) to water vapour showed improvement in the dependence on the intercalated active molecule, the best improvement was achieved for composites containing para-hydroxybenzoate molecules, suggesting that the interaction between the filler phase and the polymer plays an important role in sorption and diffusion phenomena. Incorporation of these active molecules gave antimicrobial properties to the composite films giving opportunities in the field of active packaging. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of exogenous ATP on the postharvest properties and pectin degradation of mung bean sprouts (Vigna radiata).

PubMed

Chen, Lin; Zhou, Yige; He, Zhenyun; Liu, Qin; Lai, Shaojuan; Yang, Hongshun

2018-06-15

The effects of exogenous ATP on the postharvest quality, browning and softening of mung bean (Vigna radiata) sprouts were evaluated. ATP treatment significantly alleviated the quality loss and browning events during the storage of 3 days. It also reduced the oxidant damage by inducing high activities of peroxidase (9.3-13.9%) and superoxide dismutase (8.8-10.3%) which scavenged the reactive oxygen species (ROS) effectively. Transcriptional results indicated that ATP treatment decreased VrPL1, VrPME and VrPG1 gene expression levels more than 2 folds at some time points. Furthermore, the atomic force microscope (AFM) images revealed that the pectin degradation was notably slowed by ATP treatment and the width and height of pectin backbone were better maintained (47.1% and 45.6% higher than control without ATP treatment). The cooperative effects of ROS scavenging and decreased expressions of pectin-related genes might contribute to the deferred pectin deterioration and firmness loss by ATP treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cobtorin target analysis reveals that pectin functions in the deposition of cellulose microfibrils in parallel with cortical microtubules.

PubMed

Yoneda, Arata; Ito, Takuya; Higaki, Takumi; Kutsuna, Natsumaro; Saito, Tamio; Ishimizu, Takeshi; Osada, Hiroyuki; Hasezawa, Seiichiro; Matsui, Minami; Demura, Taku

2010-11-01

Cellulose and pectin are major components of primary cell walls in plants, and it is believed that their mechanical properties are important for cell morphogenesis. It has been hypothesized that cortical microtubules guide the movement of cellulose microfibril synthase in a direction parallel with the microtubules, but the mechanism by which this alignment occurs remains unclear. We have previously identified cobtorin as an inhibitor that perturbs the parallel relationship between cortical microtubules and nascent cellulose microfibrils. In this study, we searched for the protein target of cobtorin, and we found that overexpression of pectin methylesterase and polygalacturonase suppressed the cobtorin-induced cell-swelling phenotype. Furthermore, treatment with polygalacturonase restored the deposition of cellulose microfibrils in the direction parallel with cortical microtubules, and cobtorin perturbed the distribution of methylated pectin. These results suggest that control over the properties of pectin is important for the deposition of cellulose microfibrils and/or the maintenance of their orientation parallel with the cortical microtubules. © 2010 The Authors. The Plant Journal © 2010 Blackwell Publishing Ltd.

Evidence for in vitro binding of pectin side chains to cellulose.

PubMed

Zykwinska, Agata W; Ralet, Marie-Christine J; Garnier, Catherine D; Thibault, Jean-François J

2005-09-01

Pectins of varying structures were tested for their ability to interact with cellulose in comparison to the well-known adsorption of xyloglucan. Our results reveal that sugar beet (Beta vulgaris) and potato (Solanum tuberosum) pectins, which are rich in neutral sugar side chains, can bind in vitro to cellulose. The extent of binding varies with respect to the nature and structure of the side chains. Additionally, branched arabinans (Br-Arabinans) or debranched arabinans (Deb-Arabinans; isolated from sugar beet) and galactans (isolated from potato) were shown bind to cellulose microfibrils. The adsorption of Br-Arabinan and galactan was lower than that of Deb-Arabinan. The maximum adsorption affinity of Deb-Arabinan to cellulose was comparable to that of xyloglucan. The study of sugar beet and potato alkali-treated cell walls supports the hypothesis of pectin-cellulose interaction. Natural composites enriched in arabinans or galactans and cellulose were recovered. The binding of pectins to cellulose microfibrils may be of considerable significance in the modeling of primary cell walls of plants as well as in the process of cell wall assembly.

Low temperature caused modifications in the arrangement of cell wall pectins due to changes of osmotic potential of cells of maize leaves (Zea mays L.).

PubMed

Bilska-Kos, Anna; Solecka, Danuta; Dziewulska, Aleksandra; Ochodzki, Piotr; Jończyk, Maciej; Bilski, Henryk; Sowiński, Paweł

2017-03-01

The cell wall emerged as one of the important structures in plant stress responses. To investigate the effect of cold on the cell wall properties, the content and localization of pectins and pectin methylesterase (PME) activity, were studied in two maize inbred lines characterized by different sensitivity to cold. Low temperature (14/12 °C) caused a reduction of pectin content and PME activity in leaves of chilling-sensitive maize line, especially after prolonged treatment (28 h and 7 days). Furthermore, immunocytohistological studies, using JIM5 and JIM7 antibodies, revealed a decrease of labeling of both low- and high-methylesterified pectins in this maize line. The osmotic potential, quantified by means of incipient plasmolysis was lower in several types of cells of chilling-sensitive maize line which was correlated with the accumulation of sucrose. These studies present new finding on the effect of cold stress on the cell wall properties in conjunction with changes in the osmotic potential of maize leaf cells.

Immobilization of flavan-3-ols onto sensor chips to study their interactions with proteins and pectins by SPR

NASA Astrophysics Data System (ADS)

Watrelot, Aude A.; Tran, Dong Tien; Buffeteau, Thierry; Deffieux, Denis; Le Bourvellec, Carine; Quideau, Stéphane; Renard, Catherine M. G. C.

2016-05-01

Interactions between plant polyphenols and biomacromolecules such as proteins and pectins have been studied by several methods in solution (e.g. isothermal titration calorimetry, dynamic light scattering, nuclear magnetic resonance and spectrophotometry). Herein, these interactions were investigated in real time by Surface Plasmon Resonance (SPR) analysis after immobilization of flavan-3-ols onto a sensor chip surface. (-)-epicatechin, (+)-catechin and flavan-3-ol oligomers with an average degree of polymerization of 2 and 8 were chemically modified using N-(2-(tritylthio)ethyl)propiolamide in order to introduce a spacer unit onto the catecholic B ring. Modified flavan-3-ols were then immobilized onto a carboxymethylated dextran surface (CM5). Immobilization was validated and further verified by evaluating flavan-3-ol interaction with bovine serum albumin (BSA), poly-L-proline or commercial pectins. BSA was found to have a stronger association with monomeric flavan-3-ols than oligomers. SPR analysis of selected flavan-3-ols immobilized onto CM5 sensor chips showed a stronger association for citrus pectins than apple pectins, regardless of flavan-3-ol degree of polymerization.

Assembling nanoparticle coatings to improve the drug delivery performance of lipid based colloids

NASA Astrophysics Data System (ADS)

Simovic, Spomenka; Barnes, Timothy J.; Tan, Angel; Prestidge, Clive A.

2012-02-01

Lipid based colloids (e.g. emulsions and liposomes) are widely used as drug delivery systems, but often suffer from physical instabilities and non-ideal drug encapsulation and delivery performance. We review the application of engineered nanoparticle layers at the interface of lipid colloids to improve their performance as drug delivery systems. In addition we focus on the creation of novel hybrid nanomaterials from nanoparticle-lipid colloid assemblies and their drug delivery applications. Specifically, nanoparticle layers can be engineered to enhance the physical stability of submicron lipid emulsions and liposomes, satbilise encapsulated active ingredients against chemical degradation, control molecular transport and improve the dermal and oral delivery characteristics, i.e. increase absorption, bioavailability and facilitate targeted delivery. It is feasible that hybrid nanomaterials composed of nanoparticles and colloidal lipids are effective encapsulation and delivery systems for both poorly soluble drugs and biological drugs and may form the basis for the next generation of medicines. Additional pre-clinical research including specific animal model studies are required to advance the peptide/protein delivery systems, whereas the silica lipid hybrid systems have now entered human clinical trials for poorly soluble drugs.

A Smart Responsive Dual Aptamers-Targeted Bubble-Generating Nanosystem for Cancer Triplex Therapy and Ultrasound Imaging.

PubMed

Zhao, Feifei; Zhou, Jie; Su, Xiangjie; Wang, Yuhui; Yan, Xiaosa; Jia, Shaona; Du, Bin

2017-05-01

The absence of targeted, single treatment methods produces low therapeutic value for treating cancers. To increase the accumulation of drugs in tumors and improve the treatment effectiveness, near-infrared 808 nm photothermal responsive dual aptamers-targeted docetaxel (DTX)-containing nanoparticles is proposed. In this system, DTX and NH 4 HCO 3 are loaded in thermosensitive liposomes. The surface of liposomes is coated with gold nanoshells and connected with sulfydryl (SH) modified AS1411 and S2.2 aptamers. The nanosystem has good biocompatibility and uniform size (diameter about 200 nm). The drug is rapidly released, reaching a maximum amount (84%) at 4 h under 808 nm laser irradiation. The experiments conducted in vitro and in vivo demonstrate the nanosystem can synergistically inhibit tumor growth by combination of chemotherapy, photothermal therapy, and biological therapy. Dual ligand functionalization significantly increases cellular uptake on breast cancer cell line (MCF-7) cells and achieves ultrasound imaging (USI) at tumor site. The results indicate that this drug delivery system is a promising theranostic agent involving light-thermal response at tumor sites, dual ligand targeted triplex therapy, and USI. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transport of NaYF4:Er3+, Yb3+ up-converting nanoparticles into HeLa cells

NASA Astrophysics Data System (ADS)

Sikora, Bożena; Fronc, Krzysztof; Kamińska, Izabela; Koper, Kamil; Szewczyk, Sebastian; Paterczyk, Bohdan; Wojciechowski, Tomasz; Sobczak, Kamil; Minikayev, Roman; Paszkowicz, Wojciech; Stępień, Piotr; Elbaum, Danek

2013-06-01

An effective, simple and practically useful method to incorporate fluorescent nanoparticles inside live biological cells was developed. The internalization time and concentration dependence of a frequently used liposomal transfection factor (Lipofectamine 2000) was studied. A user friendly, one-step technique to obtain water and organic solvent soluble Er3+ and Yb3+ doped NaYF4 nanoparticles coated with polyvinylpyrrolidone was obtained. Structural analysis of the nanoparticles confirmed the formation of nanocrystals of the desired sizes and spectral properties. The internalization of NaYF4 nanoparticles in HeLa cervical cancer cells was determined at different nanoparticle concentrations and for incubation periods from 3 to 24 h. The images revealed a redistribution of nanoparticles inside the cell, which increases with incubation time and concentration levels, and depends on the presence of the transfection factor. The study identifies, for the first time, factors responsible for an effective endocytosis of the up-converting nanoparticles to HeLa cells. Thus, the method could be applied to investigate a wide range of future ‘smart’ theranostic agents. Nanoparticles incorporated into the liposomes appear to be very promising fluorescent probes for imaging real-time cellular dynamics.

Profiling Metal Oxides with Lipids: Magnetic Liposomal Nanoparticles Displaying DNA and Proteins.

PubMed

Wang, Feng; Zhang, Xiaohan; Liu, Yibo; Lin, Zhi Yuan William; Liu, Biwu; Liu, Juewen

2016-09-19

Metal oxides include many important materials with various surface properties. For biomedical and analytical applications, it is desirable to engineer their biocompatible interfaces. Herein, a phosphocholine liposome (DOPC) and its headgroup dipole flipped counterpart (DOCP) were mixed with ten common oxides. Using the calcein leakage assay, cryo-TEM, and ζ-potential measurement, these oxides were grouped into three types. The type 1 oxides (Fe3 O4 , TiO2 , ZrO2 , Y2 O3 , ITO, In2 O3 , and Mn2 O3 ) form supported bilayers only with DOCP. Type 2 (SiO2 ) forms supported bilayers only with DOPC; type 3 (ZnO and NiO) are cationic and damage lipid membranes. Magnetic Fe3 O4 nanoparticles were further studied for conjugation of fluorophores, proteins, and DNA to the supported DOCP bilayers via lipid headgroup labeling, covalent linking, or lipid insertion. Delivery of the conjugates to cells and selective DNA hybridization were demonstrated. This work provides a general solution for coating the type 1 oxides with a simple mixing in water, facilitating applications in biosensing, separation, and nanomedicine. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PLGA/liposome hybrid nanoparticles for short-chain ceramide delivery.

PubMed

Zou, Peng; Stern, Stephan T; Sun, Duxin

2014-03-01

Rapid premature release of lipophilic drugs from liposomal lipid bilayer to plasma proteins and biological membranes is a challenge for targeted drug delivery. The purpose of this study is to reduce premature release of lipophilic short-chain ceramides by encapsulating ceramides into liposomal aqueous interior with the aid of poly (lactic-coglycolicacid) (PLGA). BODIPY FL labeled ceramide (FL-ceramide) and BODIPY-TR labeled ceramide (TR-ceramide) were encapsulated into carboxy-terminated PLGA nanoparticles. The negatively charged PLGA nanoparticles were then encapsulated into cationic liposomes to obtain PLGA/liposome hybrids. As a control, FL-ceramide and/or TR ceramide co-loaded liposomes without PLGA were prepared. The release of ceramides from PLGA/liposome hybrids and liposomes in rat plasma, cultured MDA-MB-231 cells, and rat blood circulation was compared using fluorescence resonance energy transfer (FRET) between FL-ceramide (donor) and TR-ceramide (acceptor). FRET analysis showed that FL-ceramide and TR-ceramide in liposomal lipid bilayer were rapidly released during incubation with rat plasma. In contrast, the FL-ceramide and TR-ceramide in PLGA/liposome hybrids showed extended release. FRET images of cells revealed that ceramides in liposomal bilayer were rapidly transferred to cell membranes. In contrast, ceramides in PLGA/liposome hybrids were internalized into cells with nanoparticles simultaneously. Upon intravenous administration to rats, ceramides encapsulated in liposomal bilayer were completely released in 2 min. In contrast, ceramides encapsulated in the PLGA core were retained in PLGA/liposome hybrids for 4 h. The PLGA/liposome hybrid nanoparticles reduced in vitro and in vivo premature release of ceramides and offer a viable platform for targeted delivery of lipophilic drugs.

The transcriptional activator GaaR of Aspergillus niger is required for release and utilization of d- galacturonic acid from pectin

DOE PAGES

Alazi, Ebru; Niu, Jing; Kowalczyk, Joanna E.; ...

2016-05-13

We identified the d-galacturonic acid (GA)-responsive transcriptional activator GaaR of the saprotrophic fungus, Aspergillus niger, which was found to be essential for growth on GA and polygalacturonic acid (PGA). Growth of the ΔgaaR strain was reduced on complex pectins. Genome-wide expression analysis showed that GaaR is required for the expression of genes necessary to release GA from PGA and more complex pectins, to transport GA into the cell, and to induce the GA catabolic pathway. Residual growth of ΔgaaR on complex pectins is likely due to the expression of pectinases acting on rhamnogalacturonan and subsequent metabolism of the monosaccharides othermore » than GA.« less

Application of Various Types of Liposomes in Drug Delivery Systems

PubMed Central

Alavi, Mehran; Karimi, Naser; Safaei, Mohsen

2017-01-01

Liposomes, due to their various forms, require further exploration. These structures can deliver both hydrophilic and hydrophobic drugs for cancer, antibacterial, antifungal, immunomodulation, diagnostics, ophtalmica, vaccines, enzymes and genetic elements. Preparation of liposomes results in different properties for these systems. In addition, based on preparation methods, liposomes types can be unilamellar, multilamellar and giant unilamellar; however, there are many factors and difficulties that affect the development of liposome drug delivery structure. In the present review, we discuss some problems that impact drug delivery by liposomes. In addition, we discuss a new generation of liposomes, which is utilized for decreasing the limitation of the conventional liposomes. PMID:28507932

Skin whitening effect of linoleic acid is enhanced by liposomal formulations.

PubMed

Shigeta, Yasutami; Imanaka, Hiromichi; Ando, Hideya; Ryu, Atsuko; Oku, Naoto; Baba, Naomichi; Makino, Taketoshi

2004-04-01

Linoleic acid (LA) is known to have a whitening effect on hyperpigmented skin, and is encapsulated in liposomes for topical application because of its low solubility in aqueous solution, although the effect of liposomalization of LA on the whitening activity has not been evaluated. In the present study, we evaluated the effect of liposomalization on the whitening activity of LA by using LA in ethanol, hydrogel containing LA, and hydrogel containing liposomal LA towards the UV-stimulated hyperpigmented dorsal skin of brownish guinea pigs. The whitening effect was far greater for hydrogel containing liposomal LA (0.1% w/w as a final concentration of LA) than for free LA in ethanol or hydrogel containing LA. Next, the whitening effect of LA was examined with UV-stimulated hyperpigmented human upper arm skin by using a hydrogel containing liposomal LA (0.1% LA) and non-liposomal LA (3.0, 10.0% LA). Liposomal LA (0.1%) showed a whitening effect comparable to 10.0% non-liposomal LA and was far more effective than 3.0% non-liposomal LA. These results indicate that liposomal formulations are favorable for the transdermal application of LA.

Strategies for improving the intratumoral distribution of liposomal drugs in cancer therapy

PubMed Central

Goins, Beth; Phillips, William T.; Bao, Ande

2016-01-01

Introduction A major limitation of current liposomal cancer therapies is the inability of liposome therapeutics to penetrate throughout the entire tumor mass. This inhomogeneous distribution of liposome therapeutics within the tumor has been linked to treatment failure and drug resistance. Both liposome particle transport properties and tumor microenvironment characteristics contribute to this challenge in cancer therapy. This limitation is relevant to both intravenously and intratumorally administered liposome therapeutics. Areas covered Strategies to improve the intratumoral distribution of liposome therapeutics are described. Combination therapies of intravenous liposome therapeutics with pharmacologic agents modulating abnormal tumor vasculature, interstitial fluid pressure, extracellular matrix components, and tumor associated macrophages are discussed. Combination therapies using external stimuli (hyperthermia, radiofrequency ablation, magnetic field, radiation, and ultrasound) with intravenous liposome therapeutics are discussed. Intratumoral convection-enhanced delivery (CED) of liposomal therapeutics is reviewed. Expert opinion Optimization of the combination therapies and drug delivery protocols are necessary. Further research should be conducted in appropriate cancer types with consideration of physiochemical features of liposomes and their timing sequence. More investigation of the role of tumor associated macrophages in intratumoral distribution is warranted. Intratumoral infusion of liposomes using CED is a promising approach to improve their distribution within the tumor mass. PMID:26981891

A novel application of maleimide for advanced drug delivery: in vitro and in vivo evaluation of maleimide-modified pH-sensitive liposomes.

PubMed

Li, Tianshu; Takeoka, Shinji

2013-01-01

Maleimide is a stable and easy-to-handle moiety that rapidly and covalently conjugates thiol groups of cysteine residues in proteins or peptides. Herein, we use maleimide to modify the surface of liposomes in order to obtain an advanced drug delivery system. Employing a small amount (0.3 mol%) of maleimide-polyethylene glycol (PEG) to modify the surface of the liposomes M-GGLG-liposomes, composed of 1,5-dihexadecyl N,N-diglutamyl-lysyl-L-glutamate (GGLG)/cholesterol/poly(ethylene glycol) 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (PEG5000-DSPE)/maleimide-PEG5000-Glu2C18 at a molar ratio of 5:5:0.03:0.03, drug delivery efficiency was remarkably improved both in vitro and in vivo compared to unmodified liposomes (GGLG-liposomes, composed of GGLG/cholesterol/PEG5000-DSPE/PEG5000-Glu2C18 at a molar ratio of 5:5:0.03:0.03). Moreover, this modification did not elicit any detectable increase in cytotoxicity. The maleimide-modification did not alter the physical characteristics of the liposomes such as size, zeta potential, pH sensitivity, dispersibility and drug encapsulation efficiency. However, M-GGLG-liposomes were more rapidly (≥2-fold) internalized into HeLa, HCC1954, and MDA-MB-468 cells compared to GGLG-liposomes. In vivo, M-GGLG-liposomes encapsulating doxorubicin (M-GGLG-DOX-liposomes) also showed a more potent antitumor effect than GGLG-DOX-liposomes and the widely used 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)-DOX-liposomes after two subcutaneous injections around breast cancer tissue in mice. The biodistribution of liposomes in this model was observed using an in vivo imaging system, which showed that M-GGLG-liposomes were present for significantly longer at the injection site compared to GGLG-liposomes. The outstanding biological functions of the maleimide-modified liposomes as a novel drug delivery system make them ideally suited to a wide range of applications.

A novel application of maleimide for advanced drug delivery: in vitro and in vivo evaluation of maleimide-modified pH-sensitive liposomes

PubMed Central

Li, Tianshu; Takeoka, Shinji

2013-01-01

Maleimide is a stable and easy-to-handle moiety that rapidly and covalently conjugates thiol groups of cysteine residues in proteins or peptides. Herein, we use maleimide to modify the surface of liposomes in order to obtain an advanced drug delivery system. Employing a small amount (0.3 mol%) of maleimide-polyethylene glycol (PEG) to modify the surface of the liposomes M-GGLG-liposomes, composed of 1,5-dihexadecyl N,N-diglutamyl-lysyl-L-glutamate (GGLG)/cholesterol/poly(ethylene glycol) 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (PEG5000-DSPE)/maleimide-PEG5000-Glu2C18 at a molar ratio of 5:5:0.03:0.03, drug delivery efficiency was remarkably improved both in vitro and in vivo compared to unmodified liposomes (GGLG-liposomes, composed of GGLG/cholesterol/PEG5000-DSPE/PEG5000-Glu2C18 at a molar ratio of 5:5:0.03:0.03). Moreover, this modification did not elicit any detectable increase in cytotoxicity. The maleimide-modification did not alter the physical characteristics of the liposomes such as size, zeta potential, pH sensitivity, dispersibility and drug encapsulation efficiency. However, M-GGLG-liposomes were more rapidly (≥2-fold) internalized into HeLa, HCC1954, and MDA-MB-468 cells compared to GGLG-liposomes. In vivo, M-GGLG-liposomes encapsulating doxorubicin (M-GGLG-DOX-liposomes) also showed a more potent antitumor effect than GGLG-DOX-liposomes and the widely used 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)-DOX-liposomes after two subcutaneous injections around breast cancer tissue in mice. The biodistribution of liposomes in this model was observed using an in vivo imaging system, which showed that M-GGLG-liposomes were present for significantly longer at the injection site compared to GGLG-liposomes. The outstanding biological functions of the maleimide-modified liposomes as a novel drug delivery system make them ideally suited to a wide range of applications. PMID:24143089

Use of liposomes as injectable-drug delivery systems.

PubMed

Ostro, M J; Cullis, P R

1989-08-01

The formation of liposomes and their application as delivery systems for injectable drugs are described. Liposomes are microscopic vesicles composed of one or more lipid membranes surrounding discrete aqueous compartments. These vesicles can encapsulate water-soluble drugs in their aqueous spaces and lipid-soluble drugs within the membrane itself. Liposomes release their contents by interacting with cells in one of four ways: adsorption, endocytosis, lipid exchange, or fusion. Liposome-entrapped drugs are distributed within the body much differently than free drugs; when administered intravenously to healthy animals and humans, most of the injected vesicles accumulate in the liver, spleen, lungs, bone marrow, and lymph nodes. Liposomes also accumulate preferentially at the sites of inflammation and infection and in some solid tumors; however, the reason for this accumulation is not clear. Four major factors influence liposomes' in vivo behavior and biodistribution: (1) liposomes tend to leak if cholesterol is not included in the vesicle membrane, (2) small liposomes are cleared more slowly than large liposomes, (3) the half-life of a liposome increases as the lipid dose increases, and (4) charged liposomal systems are cleared more rapidly than uncharged systems. The most advanced application of liposome-based therapy is in the treatment of systemic fungal infections, especially with amphotericin B. Liposomes are also under investigation for treatment of neoplastic disorders. Liposomes' uses in cancer therapy include encapsulation of known antineoplastic agents such as doxorubicin and methotrexate, delivery of immune modulators such as N-acetylmuramyl-L-alanine-D-isoglutamine, and encapsulation of new chemical entities that are synthesized with lipophilic segments tailored for insertion into lipid bilayers. Liposomal formulations of injectable antimicrobial agents and antineoplastic agents already are undergoing clinical testing, and most probably will receive approval for marketing in the early 1990s. Liposomal encapsulation of drugs represents a new drug delivery system that appears to offer important therapeutic advantages over existing methods of drug delivery.

Aerosolized liposomes with dipalmitoyl phosphatidylcholine enhance pulmonary absorption of encapsulated insulin compared with co-administered insulin.

PubMed

Chono, Sumio; Togami, Kohei; Itagaki, Shirou

2017-11-01

We have previously shown that aerosolized liposomes with dipalmitoyl phosphatidylcholine (DPPC) enhance the pulmonary absorption of encapsulated insulin. In this study, we aimed to compare insulin encapsulated into the liposomes versus co-administration of empty liposomes and unencapsulated free insulin, where the DPCC liposomes would serve as absorption enhancer. The present study provides the useful information for development of noninvasive treatment of diabetes. Co-administration of empty DPPC liposomes and unencapsulated free insulin was investigated in vivo to assess the potential enhancement in protein pulmonary absorption. Co-administration was compared to DPPC liposomes encapsulating insulin, and free insulin. DPPC liposomes enhanced the pulmonary absorption of unencapsulated free insulin; however, the enhancing effect was lower than that of the DPPC liposomes encapsulating insulin. The mechanism of the pulmonary absorption of unencapsulated free insulin by DPPC liposomes involved the opening of epithelial cell space in alveolar mucosa, and not mucosal cell damage, similar to that of the DPPC liposomes encapsulating insulin. In an in vitro stability test, insulin in the alveolar mucus layer that covers epithelial cells was stable. These findings suggest that, although unencapsulated free insulin spreads throughout the alveolar mucus layer, the concentration of insulin released near the absorption surface is increased by the encapsulation of insulin into DPPC liposomes and the absorption efficiency is also increased. We revealed that the encapsulation of insulin into DPPC liposomes is more effective for pulmonary insulin absorption than co-administration of DPPC liposomes and unencapsulated free insulin.

Tat peptide and hexadecylphosphocholine introduction into pegylated liposomal doxorubicin: An in vitro and in vivo study on drug cellular delivery, release, biodistribution and antitumor activity.

PubMed

Teymouri, Manouchehr; Badiee, Ali; Golmohammadzadeh, Shiva; Sadri, Kayvan; Akhtari, Javad; Mellat, Mostafa; Nikpoor, Amin Reza; Jaafari, Mahmoud Reza

2016-09-10

We have investigated the co-addition of hexadecylphosphocholine (HePC) and a Tat derived peptide (Tat), coupled to Maleimide-PEG2000-DSPE pegylated liposomal doxorubicin (PLD) in many respects, including drug and liposome cellular delivery, drug release, biodistribution, in vivo cell delivery and antitumor activity. The liposomes were HePC-free and -containing liposomes, from which liposomes with 25, 50, 100 and 200 numbers of Tat/liposome were prepared. Similarly, DiI-C18 (3)-model liposomes (DiI-L and DiI-HePC-L) were prepared. HePC and Tat increased cellular delivery of Dox and cytotoxicity in B16F0 melanoma and C26 colon carcinoma cells. Tat enhanced liposome-cell interaction and caused Dox burst release. HePC and Tat reduced the serum retention time of liposomal Dox, slightly and dramatically, respectively. In comparison, Tat-liposomes enhanced Dox delivery to liver and spleen cells 3h post-injection. Likewise, Dox content of these tissues and tumor was lower at 24h. The naïve liposomes retarded tumor growth more effectively and their related median survival time of the treated C26 bearing BALB/c mice was longer than those of Tat-liposomes (MST>45days versus MST<38days). Overall liposomes exhibiting sustained drug release and negligible cell interaction were more suitable delivery systems in targeting cancerous tumors and suppressing their growth. Copyright © 2016 Elsevier B.V. All rights reserved.

Accumulation, internalization and therapeutic efficacy of neuropilin-1-targeted liposomes

PubMed Central

Paoli, Eric E.; Ingham, Elizabeth S.; Zhang, Hua; Mahakian, Lisa M.; Fite, Brett Z.; Gagnon, M. Karen; Tam, Sarah; Kheirolomoom, Azadeh; Cardiff, Robert D.; Ferrara, Katherine W.

2014-01-01

Advancements in liposomal drug delivery have produced long circulating and very stable drug formulations. These formulations minimize systemic exposure; however, unfortunately, therapeutic efficacy has remained limited due to the slow diffusion of liposomal particles within the tumor and limited release or uptake of the encapsulated drug. Here, the carboxyl-terminated CRPPR peptide, with affinity for the receptor neuropilin-1 (NRP), which is expressed on both endothelial and cancer cells, was conjugated to liposomes to enhance the tumor accumulation. Using a pH sensitive probe, liposomes were optimized for specific NRP binding and subsequent cellular internalization using in vitro cellular assays. Liposomes conjugated with the carboxyl-terminated CRPPR peptide (termed C-LPP liposomes) bound to the NRP-positive primary prostatic carcinoma cell line (PPC-1) but did not bind to the NRP-negative PC-3 cell line, and binding was observed with liposomal peptide concentrations as low as 0.16 mol%. Binding of the C-LPP liposomes was receptor-limited, with saturation observed at high liposome concentrations. The identical peptide sequence bearing an amide terminus did not bind specifically, accumulating only with a high (2.5 mol%) peptide concentration and adhering equally to NRP positive and negative cell lines. The binding of C-LPP liposomes conjugated with 0.63 mol% of the peptide was 83-fold greater than liposomes conjugated with the amide version of the peptide. Cellular internalization was also enhanced with C-LPP liposomes, with 80% internalized following 3hr incubation. Additionally, fluorescence in the blood pool (~40% of the injected dose) was similar for liposomes conjugated with 0.63 mol% of carboxyl-terminated peptide and non-targeted liposomes at 24 hr after injection, indicating stable circulation. Prior to doxorubicin treatment, in vivo tumor accumulation and vascular targeting were increased for peptide-conjugated liposomes compared to non-targeted liposomes based on confocal imaging of a fluorescent cargo, and the availability of the vascular receptor was confirmed with ultrasound molecular imaging. Finally, over a 4-week course of therapy, tumor knockdown resulting from doxorubicin-loaded, C-LPP liposomes was similar to non-targeted liposomes in syngeneic tumor-bearing FVB mice and C-LPP liposomes reduced doxorubicin accumulation in the skin and heart and eliminated skin toxicity. Taken together, our results demonstrate that a carboxyl-terminated RXXR peptide sequence, conjugated to liposomes at a concentration of 0.63 mol%, retains long circulation but enhances binding and internalization, and reduces toxicity. PMID:24434424

In vivo monitoring of liposomal release in tumours following ultrasound stimulation.

PubMed

Evjen, Tove J; Hagtvet, Eirik; Moussatov, Alexei; Røgnvaldsson, Sibylla; Mestas, Jean-Louis; Fowler, R Andrew; Lafon, Cyril; Nilssen, Esben A

2013-08-01

Dioeleoylphosphatidylethanolamine (DOPE)-based liposomes were recently reported as a new class of liposomes for ultrasound (US)-mediated drug delivery. The liposomes showed both high stability and in vitro US-mediated drug release (sonosensitivity). In the current study, in vivo proof-of-principle of US triggered release in tumoured mice was demonstrated using optical imaging. Confocal non-thermal US was used to deliver cavitation to tumours in a well-controlled manner. To detect in vivo release, the near infrared fluorochrome Al (III) Phthalocyanine Chloride Tetrasulphonic acid (AlPcS₄) was encapsulated into both DOPE-based liposomes and control liposomes based on hydrogenated soy phosphatidylcholine (HSPC). Encapsulation causes concentration dependent quenching of fluorescence that is recovered upon AlPcS₄ release from the liposomes. Exposure of tumours to US resulted in a significant increase in fluorescence in mice administered with DOPE-based liposomes, but no change in the mice treated with HSPC-based liposomes. Thus, DOPE-based liposomes showed superior sonosensitivity compared to HSPC-based liposomes in vivo. Copyright © 2012 Elsevier B.V. All rights reserved.

Interactions of liposome carriers with infectious fungal hyphae reveals the role of β-glucans.

PubMed

Chavan, Neelam L; Young, Joseph K; Drezek, Rebekah A; Lewis, Russell; Bikram, Malavosklish

2012-09-04

Relatively little is known about how liposomal formulations modulate drug delivery to fungal pathogens. We compared patterns of hyphal cell wall binding for empty rhodmine-labeled liposomes and the clinically available amphotericin B-containing liposomal formulation (AmBisome) in Aspergillus fumigatus and Candida albicans. Following 0.5 h of coincubation with A. fumigatus , empty liposomes concentrated primarily in fungal septae along at the surface of the cell wall, suggesting that liposome uptake is concentrated in areas of the cell wall where linear glucan is exposed on the cell surface, which was confirmed by aniline blue staining. Consistent with this hypothesis, pretreatment of liposomes with soluble linear glucan (laminarin) decreased liposome binding in both Aspergillus and Candida fungal hyphae, while growth of Aspergillus hyphae in the presence of an agent that increases fungal cell wall surface exposure of linear β-glucans without cell death (caspofungin) increased liposome uptake throughout the Aspergillus fungal cell wall. Increasing the polyethylene glycol (PEG) concentration in liposomes from 0 to 30% significantly increased fungal uptake of liposomes that was only modestly attenuated when fungal cells were incubated in serum concentrations ranging from 10 to 100%. The presence of β-glucans on the fungal hyphae cell walls of Aspergillus fumigatus is one of the factors responsible for mediating the binding of liposome carriers to the hyphae and could explain possible synergy reported between liposomal amphotericin B and echinocanins.

Novel mucus-penetrating liposomes as a potential oral drug delivery system: preparation, in vitro characterization, and enhanced cellular uptake

PubMed Central

Li, Xiuying; Chen, Dan; Le, Chaoyi; Zhu, Chunliu; Gan, Yong; Hovgaard, Lars; Yang, Mingshi

2011-01-01

Background The aim of this study was to investigate the intestinal mucus-penetrating properties and intestinal cellular uptake of two types of liposomes modified by Pluronic F127 (PF127). Methods The two types of liposomes, ie, PF127-inlaid liposomes and PF127-adsorbed liposomes, were prepared by a thin-film hydration method followed by extrusion, in which coumarin 6 was loaded as a fluorescence marker. A modified Franz diffusion cell mounted with the intestinal mucus of rats was used to study the diffusion characteristics of the two types of PF127 liposomes. Cell uptake studies were conducted in Caco-2 cells and analyzed using confocal laser scanning microcopy as well as flow cytometry. Results The diffusion efficiency of the two types of PF127-modified liposomes through intestinal rat mucus was 5–7-fold higher than that of unmodified liposomes. Compared with unmodified liposomes, PF127-inlaid liposomes showed significantly higher cellular uptake of courmarin 6. PF127-adsorbed liposomes showed a lower cellular uptake. Moreover, and interestingly, the two types of PF127-modified liposomes showed different cellular uptake mechanisms in Caco-2 cells. Conclusion PF127-inlaid liposomes with improved intestinal mucus-penetrating ability and enhanced cellular uptake might be a potential carrier candidate for oral drug delivery. PMID:22163166

Fasudil and SOD packaged in peptide-studded-liposomes: Properties, pharmacokinetics and ex-vivo targeting to isolated perfused rat lungs.

PubMed

Gupta, Nilesh; Al-Saikhan, Fahad I; Patel, Brijeshkumar; Rashid, Jahidur; Ahsan, Fakhrul

2015-07-05

The present study investigated the feasibility of encapsulating two drugs, fasudil and superoxide dismutase (SOD), into liposomes for targeted and inhalational delivery to the pulmonary vasculature to treat pulmonary arterial hypertension (PAH). Nanosized liposomes were prepared by a thin-film formation and extrusion method, and the drugs were encapsulated by a modified freeze-thaw technique. The peptide CARSKNKDC (CAR), a pulmonary-specific targeting sequence, was conjugated on the surface of liposomes. Formulations were optimized for various physicochemical properties, tested for their ex-vivo and in-vivo drug absorption after intratracheal administration, and evaluated for short-term safety in healthy rats. The homogenous nanosized liposomes contained both SOD (~55% entrapment) and fasudil (~40% entrapment), and were stable at 4°C and after nebulization. Liposomes released the drugs in a controlled-release fashion. Compared with plain liposomes, CAR-liposomes increased the uptake by pulmonary endothelial and smooth muscle cells by ~2-fold. CAR-liposomes extended the biological half-lives of SOD and fasudil by ~3-fold. Ex-vivo studies demonstrated that CAR-liposomes were better retained in the lungs than plain liposomes. Bronchoalveolar lavage studies indicated the safety of peptide-equipped liposomes as pulmonary delivery carriers. Overall, this study demonstrates that CAR-liposomes may be used as inhalational carriers for SOD plus fasudil-based combination therapy for PAH. Published by Elsevier B.V.

Liposomal Drug Product Development and Quality: Current US Experience and Perspective.

PubMed

Kapoor, Mamta; Lee, Sau L; Tyner, Katherine M

2017-05-01

Research in the area of liposomes has grown substantially in the past few decades. Liposomes are lipid bilayer structures that can incorporate drug substances to modify the drug's pharmacokinetic profile thereby improving drug delivery. The agency has received over 400 liposomal drug product submissions (excluding combination therapies), and there are currently eight approved liposomal drug products on the US market. In order to identify the pain points in development and manufacturing of liposomal drug products, a retrospective analysis was performed from a quality perspective on submissions for new and generic liposomal drug products. General analysis on liposomal drug product submissions was also performed. Results indicated that 96% of the submissions were Investigational New Drug (IND) applications, 3% were New Drug Applications (NDAs), and the remaining 1% was Abbreviated New Drug Applications (ANDAs). Doxorubicin hydrochloride was the most commonly used drug substance incorporated into the liposomes (31%). The majority of the liposomal products were administered via intravenous route (84%) with cancer (various types) being the most common indication (63%). From a quality perspective, major challenges during the development of liposomal drug products included identification and (appropriate) characterization of critical quality attributes of liposomal drug products and suitable control strategies during product development. By focusing on these areas, a faster and more efficient development of liposomal drug products may be achieved. Additionally, in this way, the drug review process for such products can be streamlined.

Antileishmanial Activity of Liposomal Clarithromycin against Leishmania Major Promastigotes

PubMed Central

Sazgarnia, Ameneh; Zabolinejad, Naghmeh; Layegh, Pouran; Rajabi, Omid; Berenji, Fariba; Javidi, Zari; Salari, Roshanak

2012-01-01

Objective(s) Cutaneous leishmaniasis is a common parasitic disease which is endemic in some parts of the world. In vitro and in vivo studies have shown azithromycin efficacy on some Leishmania species. Because of structural similarity between clarithromycin and azithromycin and efficacy of clarithromycin against intracellular organisms and due to the absence of previous studies in this respect, we decided to evaluate the efficacy of clarithromycin against promastigotes of L. major in vitro. Materials and Method First, liposomal and non- liposomal clarithromycin were prepared, then both forms of the drug were incubated with promastigotes for 24 hr in NNN culture media without red phenol in the presence of 5% FCS with different concentrations as follows: 20, 40, 80, 100, 200 and 500 µg/ml. Results According to the results, clarithromycin in both liposomal and non- liposomal forms has in vitro activity against the promastigotes of L. major. The concentration of drug that killed 50% of parasites (ED 50) was 169 and 253.6 µg/ml for liposomal and non- liposomal forms, respectively which shows that lower concentrations of liposomal drug are required to have the same effect as non- liposomal drug and the liposomal form of the drug is more effective than non- liposomal form. Conclusion Clarithromycin in both liposomal and non- liposomal forms has in vitro activity against the promastigotes of L. major. PMID:23658854

PaeX, a Second Pectin Acetylesterase of Erwinia chrysanthemi 3937

PubMed Central

Shevchik, Vladimir E.; Hugouvieux-Cotte-Pattat, Nicole

2003-01-01

Erwinia chrysanthemi causes soft-rot diseases of various plants by enzymatic degradation of the pectin in plant cell walls. Pectin is a complex polysaccharide. The main chain is constituted of galacturonate residues, and some of them are modified by methyl and/or acetyl esterification. Esterases are necessary to remove these modifications and, thus, to facilitate the further degradation of the polysaccharidic chain. In addition to PaeY, the first pectin acetylesterase identified in the E. chrysanthemi strain 3937, we showed that this bacterium produces a second pectin acetylesterase encoded by the gene paeX. The paeX open reading frame encodes a 322-residue precursor protein of 34,940 Da, including a 21-amino-acid signal peptide. Analysis of paeX transcription, by using gene fusions, revealed that it is induced by pectic catabolic products and affected by catabolite repression. The expression of paeX is regulated by the repressor KdgR, which controls all the steps of pectin catabolism; by the repressor PecS, which controls most of the pectinase genes; and by catabolite regulatory protein, the global activator of sugar catabolism. The paeX gene is situated in a cluster of genes involved in the catabolism and transport of pectic oligomers. In induced conditions, the two contiguous genes kdgM, encoding an oligogalacturonate-specific porin, and paeX are both transcribed as an operon from a promoter proximal to kdgM, but transcription of paeX can also be uncoupled from that of kdgM in noninduced conditions. PaeX is homologous to the C-terminal domain of the Butyrivibrio fibriosolvens xylanase XynB and to a few bacterial esterases. PaeX contains the typical box (GxSxG) corresponding to the active site of the large family of serine hydrolases. Purified PaeX releases acetate from various synthetic substrates and from sugar beet pectin. The PaeX activity increased after previous depolymerization and demethylation of pectin, indicating that its preferred substrates are nonmethylated oligogalacturonides. PaeX is mostly found in the periplasmic space of E. chrysanthemi. These data suggest that PaeX is mainly involved in the deacetylation of esterified oligogalacturonides that enter the periplasm by the KdgM porin. PMID:12730169

PaeX, a second pectin acetylesterase of Erwinia chrysanthemi 3937.

PubMed

Shevchik, Vladimir E; Hugouvieux-Cotte-Pattat, Nicole

2003-05-01

Erwinia chrysanthemi causes soft-rot diseases of various plants by enzymatic degradation of the pectin in plant cell walls. Pectin is a complex polysaccharide. The main chain is constituted of galacturonate residues, and some of them are modified by methyl and/or acetyl esterification. Esterases are necessary to remove these modifications and, thus, to facilitate the further degradation of the polysaccharidic chain. In addition to PaeY, the first pectin acetylesterase identified in the E. chrysanthemi strain 3937, we showed that this bacterium produces a second pectin acetylesterase encoded by the gene paeX. The paeX open reading frame encodes a 322-residue precursor protein of 34,940 Da, including a 21-amino-acid signal peptide. Analysis of paeX transcription, by using gene fusions, revealed that it is induced by pectic catabolic products and affected by catabolite repression. The expression of paeX is regulated by the repressor KdgR, which controls all the steps of pectin catabolism; by the repressor PecS, which controls most of the pectinase genes; and by catabolite regulatory protein, the global activator of sugar catabolism. The paeX gene is situated in a cluster of genes involved in the catabolism and transport of pectic oligomers. In induced conditions, the two contiguous genes kdgM, encoding an oligogalacturonate-specific porin, and paeX are both transcribed as an operon from a promoter proximal to kdgM, but transcription of paeX can also be uncoupled from that of kdgM in noninduced conditions. PaeX is homologous to the C-terminal domain of the Butyrivibrio fibriosolvens xylanase XynB and to a few bacterial esterases. PaeX contains the typical box (GxSxG) corresponding to the active site of the large family of serine hydrolases. Purified PaeX releases acetate from various synthetic substrates and from sugar beet pectin. The PaeX activity increased after previous depolymerization and demethylation of pectin, indicating that its preferred substrates are nonmethylated oligogalacturonides. PaeX is mostly found in the periplasmic space of E. chrysanthemi. These data suggest that PaeX is mainly involved in the deacetylation of esterified oligogalacturonides that enter the periplasm by the KdgM porin.

Formulation, antileukemia mechanism, pharmacokinetics, and biodistribution of a novel liposomal emodin

PubMed Central

Wang, Tiechuang; Yin, Xiaodong; Lu, Yaping; Shan, Weiguang; Xiong, Subin

2012-01-01

Emodin is a multifunctional Chinese traditional medicine with poor water solubility. D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) is a pegylated vitamin E derivate. In this study, a novel liposomal-emodin-conjugating TPGS was formulated and compared with methoxypolyethyleneglycol 2000-derivatized distearoyl-phosphatidylethanolamine (mPEG2000–DSPE) liposomal emodin. TPGS improved the encapsulation efficiency and stability of emodin egg phosphatidylcholine/cholesterol liposomes. A high encapsulation efficiency of 95.2% ± 3.0%, particle size of 121.1 ± 44.9 nm, spherical ultrastructure, and sustained in vitro release of TPGS liposomal emodin were observed; these were similar to mPEG2000–DSPE liposomes. Only the zeta potential of −13.1 ± 2.7 mV was significantly different to that for mPEG2000–DSPE liposomes. Compared to mPEG2000–DSPE liposomes, TPGS liposomes improved the cytotoxicity of emodin on leukemia cells by regulating the protein levels of myeloid cell leukemia 1 (Mcl-1), B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein, which was further enhanced by transferrin. TPGS liposomes prolonged the circulation time of emodin in the blood, with the area under the concentration–time curve (AUC) 1.7 times larger than for free emodin and 0.91 times larger than for mPEG2000–DSPE liposomes. In addition, TPGS liposomes showed higher AUC for emodin in the lung and kidney than for mPEG2000–DSPE liposomes, and both liposomes elevated the amount of emodin in the heart. Overall, TPGS is a pegylated agent that could potentially be used to compose a stable liposomal emodin with enhanced therapeutics. PMID:22661889

PLGA/liposome hybrid nanoparticles for short-chain ceramide delivery

PubMed Central

Zou, Peng; Stern, Stephan T.; Sun, Duxin

2014-01-01

Purpose Rapid premature release of lipophilic drugs from liposomal lipid bilayer to plasma proteins and biological membranes is a challenge for targeted drug delivery. The purpose of this study is to reduce premature release of lipophilic short-chain ceramides by encapsulating ceramides into liposomal aqueous interior with the aid of poly( lactic-coglycolicacid) (PLGA). Methods BODIPY FL labeled ceramide (FL-ceramide) and BODIPY-TR labeled ceramide (TR-ceramide) were encapsulated into carboxy-terminated PLGA nanoparticles. The negatively charged PLGA nanoparticles were then encapsulated into cationic liposomes to obtain PLGA/liposome hybrids. As a control, FL-ceramide and/or TR ceramide co-loaded liposomes without PLGA were prepared. The release of ceramides from PLGA/liposome hybrids and liposomes in rat plasma, cultured MDA-MB-231 cells, and rat blood circulation was compared using fluorescence resonance energy transfer (FRET) between FL-ceramide (donor) and TR-ceramide (acceptor). Results FRET analysis showed that FL-ceramide and TR-ceramide in liposomal lipid bilayer were rapidly released during incubation with rat plasma. In contrast, the FL-ceramide and TR-ceramide in PLGA/liposome hybrids showed extended release. FRET images of cells revealed that ceramides in liposomal bilayer were rapidly transferred to cell membranes. In contrast, ceramides in PLGA/liposome hybrids were internalized into cells with nanoparticles simultaneously. Upon intravenous administration to rats, ceramides encapsulated in liposomal bilayer were completely released in 2 minutes. In contrast, ceramides encapsulated in the PLGA core were retained in PLGA/liposome hybrids for 4 hours. Conclusions The PLGA/liposome hybrid nanoparticles reduced in vitro and in vivo premature release of ceramides and offer a viable platform for targeted delivery of lipophilic drugs. PMID:24065591

Immunogenicity of diphtheria toxoid and poly(I:C) loaded cationic liposomes after hollow microneedle-mediated intradermal injection in mice.

PubMed

Du, Guangsheng; Leone, Mara; Romeijn, Stefan; Kersten, Gideon; Jiskoot, Wim; Bouwstra, Joke A

2018-06-02

In this study, we aimed to investigate the immunogenicity of cationic liposomes loaded with diphtheria toxoid (DT) and poly(I:C) after hollow microneedle-mediated intradermal vaccination in mice. The following liposomal formulations were studied: DT loaded liposomes, a mixture of free DT and poly(I:C)-loaded liposomes, a mixture of DT-loaded liposomes and free poly(I:C), and liposomal formulations with DT and poly(I:C) either individually or co-encapsulated in the liposomes. Reference groups were DT solution adjuvanted with or without poly(I:C) (DT/poly(I:C)). The liposomal formulations were characterized in terms of particle size, zeta potential, loading and release of DT and poly(I:C). After intradermal injection of BALB/c mice with the formulations through a hollow microneedle, the immunogenicity was assessed by DT-specific ELISAs. All formulations induced similar total IgG and IgG1 titers. However, all the liposomal groups containing both DT and poly(I:C) showed enhanced IgG2a titers compared to DT/poly(I:C) solution, indicating that the immune response was skewed towards a Th1 direction. This enhancement was similar for all liposomal groups that contain both DT and poly(I:C) in the formulations. Our results reveal that a mixture of DT encapsulated liposomes and poly(I:C) encapsulated liposomes have a similar effect on the antibody responses as DT and poly(I:C) co-encapsulated liposomes. These findings may have implications for future design of liposomal vaccine delivery systems. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Quantification of ligand density and stoichiometry on the surface of liposomes using single-molecule fluorescence imaging.

PubMed

Belfiore, Lisa; Spenkelink, Lisanne M; Ranson, Marie; van Oijen, Antoine M; Vine, Kara L

2018-05-28

Despite the longstanding existence of liposome technology in drug delivery applications, there have been no ligand-directed liposome formulations approved for clinical use to date. This lack of translation is due to several factors, one of which is the absence of molecular tools for the robust quantification of ligand density on the surface of liposomes. We report here for the first time the quantification of proteins attached to the surface of small unilamellar liposomes using single-molecule fluorescence imaging. Liposomes were surface-functionalized with fluorescently labeled human proteins previously validated to target the cancer cell surface biomarkers plasminogen activator inhibitor-2 (PAI-2) and trastuzumab (TZ, Herceptin®). These protein-conjugated liposomes were visualized using a custom-built wide-field fluorescence microscope with single-molecule sensitivity. By counting the photobleaching steps of the fluorescently labeled proteins, we calculated the number of attached proteins per liposome, which was 11 ± 4 proteins for single-ligand liposomes. Imaging of dual-ligand liposomes revealed stoichiometries of the two attached proteins in accordance with the molar ratios of protein added during preparation. Preparation of PAI-2/TZ dual-ligand liposomes via two different methods revealed that the post-insertion method generated liposomes with a more equal representation of the two differently sized proteins, demonstrating the ability of this preparation method to enable better control of liposome protein densities. We conclude that the single-molecule imaging method presented here is an accurate and reliable quantification tool for determining ligand density and stoichiometry on the surface of liposomes. This method has the potential to allow for comprehensive characterization of novel ligand-directed liposomes that should facilitate the translation of these nanotherapies through to the clinic. Copyright © 2018 Elsevier B.V. All rights reserved.

Thermo-responsive magnetic liposomes for hyperthermia-triggered local drug delivery.

PubMed

Dai, Min; Wu, Cong; Fang, Hong-Ming; Li, Li; Yan, Jia-Bao; Zeng, Dan-Lin; Zou, Tao

2017-06-01

We prepared and characterised thermo-responsive magnetic liposomes, which were designed to combine features of magnetic targeting and thermo-responsive control release for hyperthermia-triggered local drug delivery. The particle size and zeta-potential of the thermo-responsive magnetic ammonium bicarbonate (MagABC) liposomes were about 210 nm and -14 mV, respectively. The MagABC liposomes showed encapsulation efficiencies of about 15% and 82% for magnetic nanoparticles (mean crystallite size 12 nm) and doxorubicin (DOX), respectively. The morphology of the MagABC liposomes was visualised using transmission electron microscope (TEM). The MagABC liposomes showed desired thermo-responsive release. The MagABC liposomes, when physically targeted to tumour cells in culture by a permanent magnetic field yielded a substantial increase in intracellular accumulation of DOX as compared to non-magnetic ammonium bicarbonate (ABC) liposomes. This resulted in a parallel increase in cytotoxicity for DOX loaded MagABC liposomes over DOX loaded ABC liposomes in tumour cells.

Ultrasound-mediated drug delivery using liposomes modified with a thermosensitive polymer.

PubMed

Ninomiya, Kazuaki; Kawabata, Shinya; Tashita, Hiroyuki; Shimizu, Nobuaki

2014-01-01

Ultrasound-mediated drug delivery was established using liposomes that were modified with the thermosensitive polymer (TSP) poly(NIPMAM-co-NIPAM), which sensitized the liposomes to high temperatures. TSP-modified liposomes (TSP liposomes) released encapsulated calcein under 1 MHz ultrasound irradiation at 0.5 W/cm(2) for 120 s as well as the case under incubation at 42 °C for 15 min. In addition, uptake of the drug released from TSP liposomes by cancer cells was enhanced by ultrasound irradiation. In a cell injury assay using doxorubicin (DOX)-loaded TSP liposomes and ultrasound irradiation, cell viability of HepG2 cells at 6 h after ultrasound irradiation (1 MHz, 0.5 W/cm(2) for 30 s) with DOX-loaded TSP liposomes (TSP/lipid ratio=1) was 60%, which was significantly lower than that of the control conditions such as DOX-loaded TSP liposomes alone and DOX-loaded intact liposomes under ultrasound irradiation. Copyright © 2013 Elsevier B.V. All rights reserved.

Design considerations for liposomal vaccines: Influence of formulation parameters on antibody and cell-mediated immune responses to liposome associated antigens

PubMed Central

Watson, Douglas S.; Endsley, Aaron N.; Huang, Leaf

2012-01-01

Liposomes (phospholipid bilayer vesicles) are versatile and robust delivery systems for induction of antibody and T lymphocyte responses to associated subunit antigens. In the last 15 years, liposome vaccine technology has matured and now several vaccines containing liposome-based adjuvants have been approved for human use or have reached late stages of clinical evaluation. Given the intensifying interest in liposome-based vaccines, it is important to understand precisely how liposomes interact with the immune system and stimulate immunity. It has become clear that the physicochemical properties of liposomal vaccines – method of antigen attachment, lipid composition, bilayer fluidity, particle charge, and other properties – exert dramatic effects on the resulting immune response. Here, we present a comprehensive review of the physicochemical properties of liposomal vaccines and how they influence immune responses. A discussion of novel and emerging immunomodulators that are suitable for inclusion in liposomal vaccines is also presented. Through a comprehensive analysis of the body of liposomal vaccine literature, we enumerate a series of principles that can guide the rational design of liposomal vaccines to elicit immune responses of a desired magnitude and quality. We also identify major unanswered questions in the field, pointing the direction for future study. PMID:22306376

Stealth liposomes: review of the basic science, rationale, and clinical applications, existing and potential

PubMed Central

Immordino, Maria Laura; Dosio, Franco; Cattel, Luigi

2006-01-01

Among several promising new drug-delivery systems, liposomes represent an advanced technology to deliver active molecules to the site of action, and at present several formulations are in clinical use. Research on liposome technology has progressed from conventional vesicles (“first-generation liposomes”) to “second-generation liposomes”, in which long-circulating liposomes are obtained by modulating the lipid composition, size, and charge of the vesicle. Liposomes with modified surfaces have also been developed using several molecules, such as glycolipids or sialic acid. A significant step in the development of long-circulating liposomes came with inclusion of the synthetic polymer poly-(ethylene glycol) (PEG) in liposome composition. The presence of PEG on the surface of the liposomal carrier has been shown to extend blood-circulation time while reducing mononuclear phagocyte system uptake (stealth liposomes). This technology has resulted in a large number of liposome formulations encapsulating active molecules, with high target efficiency and activity. Further, by synthetic modification of the terminal PEG molecule, stealth liposomes can be actively targeted with monoclonal antibodies or ligands. This review focuses on stealth technology and summarizes pre-clinical and clinical data relating to the principal liposome formulations; it also discusses emerging trends of this promising technology. PMID:17717971

HEPC-based liposomes trigger cytokine release from peripheral blood cells: effects of liposomal size, dose and lipid composition.

PubMed

Yamamoto, Sayaka; Ishida, Tatsuhiro; Inoue, Akiko; Mikami, Junko; Muraguchi, Masahiro; Ohmoto, Yasukazu; Kiwada, Hiroshi

2002-04-02

The immune response caused by liposome stimulation was studied by assessing the level of several cytokines released from human peripheral blood cells. Liposome stimulation resulted in the release of IL-6, IL-10, IL-1beta, TNF-alpha and IFN-gamma. The size of the liposomes affected the degree of the cytokine releases with larger sized liposomes causing higher levels of cytokine induction. In addition, it appears that the lipid composition of liposomes had no effect on the degree of cytokine release. The release of cytokines occurred even in the absence of serum, suggesting that serum proteins did not contribute to liposome stimulation in peripheral blood cells. The release of cytokines induced by liposome stimulation was inhibited by the presence of either protein kinase-C (PKC) or protein tyrosine kinase (PTK) inhibitor, but not by the presence of an endocytosis inhibitor. This indicates that signal transduction via PKC or PTK is necessary, in order for human peripheral blood cells to release cytokines (IL-6, IL-10, IL-1beta, TNF-alpha and IFN-gamma) as the result of liposome stimulation. These quantitative data on the release of cytokines by liposomal stimulation provide useful information for the development of rational drug delivery systems and the safety of cytokine induction via the use of liposomes.