Purification and Characterization of Bioactive Compounds from Styela clava

The immunomodulatory activity of extract from Styela clava was studied systematically based on activity tracking in vitro in order to find out novel-structured secondary metabolite. The proliferation rates of mouse splenic lymphocytes and peritoneal macrophages were used as screening index, as well as NO release promoting activities. The crude extract (CE) and its different polar fractions from S. clava all exhibited proliferative activity of splenolymphocytes and mouse macrophages, as well as NO release promoting activities, among which petroleum ether fraction (PE) showed the strongest effect. The antioxidant experiment in vitro showed that CE demonstrated antioxidant ability in 1,1-diphenyl-2-picrylhydrazyl (DPPH) system and the beta carotene-linoleic acid system; the activity of ethyl acetate fraction (ET) was much stronger than that of the others. Further isolated by silica gel column chromatography, ET was classified into seven sub-components (E1∼E7) listed in the order of activity as E5 > E6 > E4 > E3 > E7 > E2 > E1. Five compounds were separated as (1) cholesteric-7-en-3 -ol, (2) cholesteric-4-en-3 ,6 -diol, (3) cholesterol, (4) batilol, and (5) ceramide, among which (1), (2), and (4) were isolated for the first time from S. clava

The Man-PTS subunit ⅡC is responsible for the sensitivity of Listeria monocytogenes to durancin GL

Target cell recognition is an important issue in the realization of bacteriocin's activity. In this report, we provide genetic and biochemical evidence of durancin GL, a new bacteriocin produced by Enterococcus durans 41D, and use ⅡC subunit in the mannose phosphotransferase system (Man-PTS) of Listeria monocytogenes as target/receptor. First, the L. monocytogenes mutants with Man-PTS IIC or IID deletion were constructed with the vector pHoss1. Then, the utilization of glucose and mannose and the sensitivity to durancin GL of the mutant strains were investigated. Afterward, the interactions between durancin GL and the subunits of IIC or IID in Man-PTS of L. monocytogenes were characterized by yeast two-hybrid system. The results showed that the L. monocytogenes mutants with either IIC or IID deletion were not only resistant to durancin GL, but also their absorption and utilization of glucose and mannose were not disturbed by the presence of durancin GL. Finally, in situ detection of the interaction between durancin GL and Man-PTS subunits of IIC or IID by yeast two-hybrid system revealed that there was a strong interaction between durancin GL and Man-PTS subunit IIC. However, the interaction between durancin GL and Man-PTS subunit IID was not present or weak. Based on the experimental evidence above, the Man-PTS subunit IIC is responsible for the sensitivity of L. monocytogenes to bacteriocin durancin GL

Development and optimization of an immunoassay for the detection of Hg(II) in lake water

Abstract In this paper, an indirect competitive enzyme‐linked immunosorbent assay (IC‐ELISA) has been developed and optimized to detect Hg(II) in tap water and lake water based on a monoclonal antibody (mAb‐A24). Some stabilizing additives (Gelatin, bovine serum albumin [BSA], polyvinyl alcohol [PVA], and polyvinyl pyrrolidone [PVP]) and surfactant (Tween‐20) have been investigated thoroughly in the optimization process. Under the optimal condition, the 50% half maximal inhibitory concentration (IC50) and limit of detection (LOD) were 1.68 and 0.079 ng/ml, respectively. These anti‐Hg mAbs also have some affinity with methyl mercury (CH3Hg) and with no cross‐reactivity with other thirteen metal ions. The developed method has shown satisfactory recovery of Hg(II), ranged between 91% and 116%, from tap water and lake water. Therefore, this immunoassay can be used to detect trace Hg(II) in environment water

The effect of refining process on the physicochemical properties and micronutrients of rapeseed oils.

Information on the physicochemical variability in rapeseed oil from different varieties during each refining process is lacking. Our purpose was to investigate the physicochemical properties, micronutrients and oxidative stability of the oil extracted from the five varieties of rapeseeds during their different stages of refining process. Increase in the acid value, peroxide value and p-anisidine value were detected in the refining, while content of tocopherols, sterols, β-carotene and phenols, which are regarded as important nutritional compounds diminished. Moreover, the loss rate of total phytosterols of all oils during neutralization (9.23-7.3%) and deodorization (9.97-8.27%) were higher than that of degumming (3.01-0.87%) and bleaching (2.75-1.18%). Deodorization affected total tocopherols contents the most, followed by bleaching, neutralization and degumming. There was a remarkable reduction in total content of phenol, β-carotene and oxygen radical absorbance of all oils during refining. The accumulated information can be used in looking for the optimum condition to meet the basic requirements for oil and minimize micronutrients losses so as to increase their market value

Plant protein nanogel–based patchy Janus particles with tunable anisotropy for perishable food preservation

Abstract Janus particles with anisotropic surfaces possess considerable potential for biological functionalization. However, little is known about the effect of surface anisotropy of Janus particles on the shelf life of perishable food. Herein, plant protein–based nanogels prepared by acylated rapeseed protein isolate (ARPI) are exploited as novel building blocks to decorate the surface of latex particles for Janus particle synthesis. The surface anisotropy of patchy latex particles can be facilely tailored via the suspension polymerization of the Pickering emulsion using ARPI nanogels as stabilizers. The surface distribution of ARPI nanogel on latex particles can be controlled by varying the aqueous phase conditions, and thus, the tunable hydrophilic–lipophilic balance (viz., Janus balance) varied from 0.78 to 1.76 for resulting patchy latex particles. Patchy latex particles with varied Janus balance were further investigated for the effects of their anti‐perishable coatings on perishable fruit preservation. The anisotropic patchy latex particles can act as a novel type of antibacterial agent to inhibit Ascomycota microorganisms’ growth on the surface of fruits and reduce the dehydration and respiration of fruits, all of which devote to a lengthened shelf life while being safe. Furthermore, it is found that the patchy latex particle with a spatial pattern of a hydrophobic area on its surface occupying 51.3% (Janus balance = 0.95) extends the shelf life of perishable food more effectively than that of other spatial arrangements. Overall, the exploration of anisotropic Janus particles offers an alternative strategy to preserve perishable food without using antimicrobial agents

Alanine-Scanning Mutational Analysis of Durancin GL Reveals Residues Important for Its Antimicrobial Activity

Durancin GL is a novel class IIa bacteriocin with 43 residues produced by Enterococcus durans 41D. This bacteriocin demonstrates narrow inhibition spectrum and potent antimicrobial activity against several Listeria monocytogenes strains, including nisin-resistant L. monocytogenes NR30. A systematic alanine-scanning mutational analysis with site-directed mutagenesis was performed to analyze durancin GL residues important for antimicrobial activity and specificity. Results showed that three mutations lost their antimicrobial activity, ten mutations demonstrated a decreased effect on the activity, and seven mutations exhibited relatively high activity. With regard to inhibitory spectrum, four mutants demonstrated a narrower antimicrobial spectrum than wild-type durancin GL. Another four mutants displayed a broader target cell spectrum and increased potency relative to wild-type durancin GL. These findings broaden our understanding of durancin GL residues important for its antimicrobial activity and contribute to future rational design of variants with increased potency

Protective Effect of Polyphenols Extract of Adlay (<em>Coix lachryma-jobi </em>L. var<em>. ma-yuen Stapf</em>) on Hypercholesterolemia-Induced Oxidative Stress in Rats

The present study examines the effect of polyphenols extract of adlay (<em>Coix lachryma-jobi </em>L. var.<em> ma-yuen Stapf</em>) (APE) on high cholesterol diet fed rats (HCD). APE was orally administrated by gavage at doses of 10, 40 and 200 mg total phenolics/kg body weight of rats once a day for 28 days. At the end of four weeks, serum triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C), and markers of oxidative stress <em>viz</em>., malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the serum and liver of HCD and normal rats were assessed and compared. The results showed that administration of APE was significantly effective in decreasing the serum levels of TC, LDL-C and MDA, increasing the serum level of HDL-C and antioxidant capacity. In addition, oral gavage of APE could also increase the antioxidant capacity, CAT and GSH-Px activities in liver. These results suggested that APE exerted a high hypocholesterolemic and antioxidant activities, which might be characterized by a protective effect on cardiovascular health <em>in vivo</em>

Purification and Characterization of Bioactive Compounds from Styela clava

The immunomodulatory activity of extract from Styela clava was studied systematically based on activity tracking in vitro in order to find out novel-structured secondary metabolite. The proliferation rates of mouse splenic lymphocytes and peritoneal macrophages were used as screening index, as well as NO release promoting activities. The crude extract (CE) and its different polar fractions from S. clava all exhibited proliferative activity of splenolymphocytes and mouse macrophages, as well as NO release promoting activities, among which petroleum ether fraction (PE) showed the strongest effect. The antioxidant experiment in vitro showed that CE demonstrated antioxidant ability in 1,1-diphenyl-2-picrylhydrazyl (DPPH) system and the beta carotene-linoleic acid system; the activity of ethyl acetate fraction (ET) was much stronger than that of the others. Further isolated by silica gel column chromatography, ET was classified into seven sub-components (E1 similar to E7) listed in the order of activity as E5 > E6 > E4 > E3 > E7 > E2 > E1. Five compounds were separated as (1) cholesteric-7-en-3 beta-ol, (2) cholesteric-4-en-3 beta,6 beta-diol, (3) cholesterol, (4) batilol, and (5) ceramide, among which (1), (2), and (4) were isolated for the first time from S. clava.The immunomodulatory activity of extract from Styela clava was studied systematically based on activity tracking in vitro in order to find out novel-structured secondary metabolite. The proliferation rates of mouse splenic lymphocytes and peritoneal macrophages were used as screening index, as well as NO release promoting activities. The crude extract (CE) and its different polar fractions from S. clava all exhibited proliferative activity of splenolymphocytes and mouse macrophages, as well as NO release promoting activities, among which petroleum ether fraction (PE) showed the strongest effect. The antioxidant experiment in vitro showed that CE demonstrated antioxidant ability in 1,1-diphenyl-2-picrylhydrazyl (DPPH) system and the beta carotene-linoleic acid system; the activity of ethyl acetate fraction (ET) was much stronger than that of the others. Further isolated by silica gel column chromatography, ET was classified into seven sub-components (E1 similar to E7) listed in the order of activity as E5 > E6 > E4 > E3 > E7 > E2 > E1. Five compounds were separated as (1) cholesteric-7-en-3 beta-ol, (2) cholesteric-4-en-3 beta,6 beta-diol, (3) cholesterol, (4) batilol, and (5) ceramide, among which (1), (2), and (4) were isolated for the first time from S. clava