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Gupta A.,Maharshi Dayanand University | Gupta A.,Banasthali University | Tiwari S.K.,Maharshi Dayanand University | Tiwari S.K.,Banasthali University | And 4 more authors.
Probiotics and Antimicrobial Proteins | Year: 2016

Enterocin LD3 was purified using activity-guided multistep chromatography techniques such as cation-exchange and gel-filtration chromatography. The preparation’s purity was tested using reverse-phase ultra-performance liquid chromatography. The specific activity was tested to be 187.5 AU µg−1 with 13-fold purification. Purified enterocin LD3 was heat stable up to 121 °C (at 15 psi pressure) and pH 2–6. The activity was lost in the presence of papain, reduced by proteinase K, pepsin and trypsin, but was unaffected by amylase and lipase, suggesting proteinaceous nature of the compound and no role of carbohydrate and lipid moieties in the activity. MALDI-TOF/MS analysis of purified enterocin LD3 resolved m/z 4114.6, and N-terminal amino acid sequence was found to be H2NQGGQANQ–COOH suggesting a new bacteriocin. Dissipation of membrane potential, loss of internal ATP and bactericidal effect were recorded when indicator strain Micrococcus luteus was treated with enterocin LD3. It inhibited Gram-positive and Gram-negative bacteria including human pathogens such as Staphylococcus aureus, Pseudomonas fluorescens, Pseudomonas aeruginosa, Salmonella typhi, Shigella flexneri, Listeria monocytogenes, Escherichia coli O157:H7, E. coli (urogenic, a clinical isolate) and Vibrio sp. These properties of purified enterocin LD3 suggest its applications as a food biopreservative and as an alternative to clinical antibiotics. © 2016 Springer Science+Business Media New York Source

Faig A.,Rutgers University | Fitzgerald P.O.,Rutgers University | Fitzgerald P.O.,York College | Chikindas M.,Rutgers University | And 6 more authors.
Langmuir | Year: 2015

Cationic amphiphiles have received increasing attention as antimicrobials given their unique ability to disrupt bacteria cell membranes. While extensive research has demonstrated that amphiphiles' hydrophobic-to-charge ratio significantly modulates antibacterial activity, less work has focused on elucidating the specific impact of charge location on amphiphile bioactivity. In this study, two series of cationic amphiphiles, termed bola-like and gemini-like, were synthesized with analogous hydrophobic-to-charge ratios yet differing charge location, and their resulting antibacterial activity was assessed. Bola-like amphiphiles exhibited preferential activity against two Gram-positive bacteria, with activity increasing with increasing hydrophobicity, whereas gemini-like amphiphiles were active against both Gram-positive and Gram-negative bacteria, with activity decreasing with increasing hydrophobicity. After identifying lead compounds from each amphiphile series (bola- and gemini-like), biophysical experiments indicated that both amphiphiles were membrane-active; notably, the lead gemini-like amphiphile exhibited a strong dependence on electrostatic interactions for membrane interaction. In contrast, the lead bola-like amphiphile exhibited a reliance on both hydrophobic and electrostatic contributions. These results demonstrate that charge location significantly impacts cationic amphiphiles' antibacterial and membrane activity. © 2015 American Chemical Society. Source

Ozvural E.B.,Cankiri Karatekin University | Huang Q.,Rutgers University | Chikindas M.L.,Rutgers University | Chikindas M.L.,New Jersey Institute for Food
LWT - Food Science and Technology | Year: 2016

This study was aimed at the comparison of the effects of green tea extract (GTE) added with different techniques (direct addition, edible coating and encapsulation) on quality (particularly oxidative) and microbiological properties of hamburger patties. High molecular weight (1000 kDa) chitosan was utilized as the coating material and chitosan-TPP solution was formed for encapsulation of the extract. At the beginning (day 0) and in the middle of storage (day 4), control patty and the patties including GTE had higher pH values than the coated patties (p < 0.05) probably due to the inhibition effect of coating materials as a barrier on microbiological growth. TBARS value of control patty was higher than the other treatments in each measuring time (on the days 0, 4 and 8). This showed that enrichment of treatments by adding or coating with encapsulated green tea extract solution led to attenuation effect against lipid oxidation. However, TBARS value of all the treatments increased throughout storage, except the treatment coated with 1% (w/w) chitosan solution (p > 0.05). According to microbiological results, there were significant differences among the treatments. © 2015 Elsevier Ltd. Source

Ting Y.,Rutgers University | Jiang Y.,Rutgers University | Lan Y.,Rutgers University | Xia C.,Rutgers University | And 4 more authors.
Molecular Pharmaceutics | Year: 2015

The oral bioavailability of hydrophobic compound is usually limited by the poor aqueous solubility in the gastrointestinal (GI) tract. Various oral formulations were developed to enhance the systemic concentration of such molecules. Moreover, compounds with high melting temperature that appear as insoluble crystals imposed a great challenge to the development of oral vehicle. Polymethoxyflavone, an emerging category of bioactive compounds with potent therapeutic efficacies, were characterized as having a hydrophobic and highly crystalline chemical structure. To enhance the oral dosing efficiency of polymethoxyflavone, a viscoelastic emulsion system with a high static viscosity was developed and optimized using tangeretin, one of the most abundant polymethoxyflavones found in natural sources, as a modeling compound. In the present study, different in vitro and in vivo models were used to mechanistically evaluate the effect of emulsification on oral bioavailability of tangeretin. In vitro lipolysis revealed that emulsified tangeretin was digested and became bioaccessible much faster than unprocessed tangeretin oil suspension. By simulating the entire human GI tract, TNO's gastrointestinal model (TIM-1) is a valuable tool to mechanistically study the effect of emulsification on the digestion events that lead to a better oral bioavailability of tangeretin. TIM-1 result indicated that tangeretin was absorbed in the upper GI tract. Thus, a higher oral bioavailability can be expected if the compound becomes bioaccessible in the intestinal lumen soon after dosing. In vivo pharmacokinetics analysis on mice again confirmed that the oral bioavailability of tangeretin increased 2.3 fold when incorporated in the viscoelastic emulsion than unformulated oil suspension. By using the combination of in vitro and in vivo models introduced in this work, the mechanism that underlie the effect of viscoelastic emulsion on the oral bioavailability of tangeretin was well-elucidated. (Graph Presented). © 2015 American Chemical Society. Source

Sembongi H.,University of Cambridge | Miranda M.,Rovira i Virgili University | Han G.-S.,New Jersey Institute for Food | Fakas S.,New Jersey Institute for Food | And 5 more authors.
Journal of Biological Chemistry | Year: 2013

Lipins are evolutionarily conserved Mg2+-dependent phosphatidate phosphatase (PAP) enzymes with essential roles in lipid biosynthesis. Mammals express three paralogues: lipins 1, 2, and 3. Loss of lipin 1 in mice inhibits adipogenesis at an early stage of differentiation and results in a lipodystrophic phenotype. The role of lipins at later stages of adipogenesis, when cells initiate the formation of lipid droplets, is less well characterized. We found that depletion of lipin 1, after the initiation of differentiation in 3T3-L1 cells but before the loading of lipid droplets with triacylglycerol, results in a reciprocal increase of lipin 2, but not lipin 3. We generated 3T3-L1 cells where total lipin protein and PAP activity levels are down-regulated by the combined depletion of lipins 1 and 2 at day 4 of differentiation. These cells still accumulated triacylglycerol but displayed a striking fragmentation of lipid droplets without significantly affecting their total volume per cell. This was due to the lack of the PAP activity of lipin 1 in adipocytes after day 4 of differentiation, whereas depletion of lipin 2 led to an increase of lipid droplet volume per cell. We propose that in addition to their roles during early adipogenesis, lipins also have a role in lipid droplet biogenesis. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc. Source

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