Enhanced antiviral activity of soybean β-conglycinin-derived peptides by acylation with saturated fatty acids

Abstract: Peptide mixtures prepared from soybean β‐conglycinin (7S‐peptides) were acylated with saturated fatty acids of different chain length (6C‐18C) in order to improve their antiviral activity against Feline calicivirus (FCV) strain F9 which is a typical norovirus surrogate. Among the fatty acids varieties, it was revealed that 7S‐peptides acylated with myristic and palmitic acids potently inhibited FCV replication. Myristorylation and palmitoylation of 7S‐peptides kept host cells viability at 91.51% and 98.90%, respectively. The infectivity of FCV on Crandell–Reese feline kidney cells was further determined after exposure of initial titer of 10^6.47 TCID₅₀/mL. Myristoylated and palmitoylated 7S‐peptides significantly (P < 0.006) reduced FCV infectivity as compared to native 7S‐peptides. Native 7S‐peptides showed 25% FCV inhibitory activity while myristoylated and palmitoylated 7S‐peptides exhibited 98.59% and 99.98% reduction in FCV infectivity, respectively. Myristoylated and palmitoylated 7S‐peptides demonstrated higher anti‐FCV activity in a wide range of concentration with complete reduction at 25 μg/mL. Surface hydrophobicity was significantly (P < 0.05) increased after attachment of long hydrocarbon fatty acids to 7S‐peptides as supported by changes in fluorescence intensity. Enzymatic hydrolysis together with acylation will give an insight into surface and physiological functional lipopeptides derived from soy β‐conglycinin.     

Novel method for producing amorphous rice flours by milling without adding water

The present study investigated a novel milling method for producing amorphous rice starch without adding water. A new type of milling machine was developed (termed the shear and heat milling machine (SHMM)), which is capable of applying mechanical shear and heat during the milling process. The SHMM consisted of a pair of rice mortars attached to a servomotor and a ring heater. The heater was installed on the upper mortar; the temperature of the upper mortar was monitored and controlled by a thermal controller. Wide‐angle X‐ray diffraction (WAXD) analysis was used to determine the crystallinities of starch in rice flour samples produced using the SHMM at different milling temperatures. The WAXD data for milled rice flour that had been heated exhibited no diffraction peaks. This experimental result demonstrates that the developed SHMM produces amorphous rice starch easily by milling with heating without the addition of water. The milling conditions such as the shear and heat applied can be used to control the crystallinity of starch in rice.     

Effects of U-50,488H on scopolamine-, mecamylamine- and dizocilpine-induced learning and memory impairment in rats

The role of kappa opioid receptor agonists in learning and memory is controversial. In the present study, the effects of U-50,488H on scopolamine-, mecamylamine- and dizocilpine-induced learning and memory impairments in rats were investigated. Scopolamine (3.3 mumol/kg s.c.), a muscarinic cholinergic antagonist, and mecamylamine (40 mumol/kg s.c.), a nicotinic cholinergic antagonist, significantly impaired learning and memory in rats in a step-through type passive avoidance test. Administration of U-50,488H (0.17 or 0.51 mumol/kg s.c.) 25 min before the acquisition trial reversed the impairment of learning and memory induced by scopolamine and mecamylamine. Although low doses of scopolamine (0.17 mumol/kg) and mecamylamine (12 mumol/kg) had no effect, concurrent administration of both antagonists induced impairment of learning and memory. Scopolamine significantly increased acetylcholine release in the hippocampus as determined by in vivo brain microdialysis. On the other hand, mecamylamine significantly decreased acetylcholine release. U-50,488H completely blocked the decrease in acetylcholine release induced by mecamylamine, whereas it only partially blocked the increase of acetylcholine induced by scopolamine. On the other hand, an endogenous kappa opioid receptor agonist, dynorphin A (1-13), did not block the increase in acetylcholine release induced by scopolamine. The antagonistic effect of U-50,488H was abolished by pretreatment with nor-binaltorphimine (4.9 nmol/rat i.c.v.), a selective kappa opioid receptor antagonist. U-50,488H did not affect the impairment of learning and memory induced by the blockade of NMDA receptors by dizocilpine ((+)-MK-801). These results suggest that U-50,488H reverses the impairment of learning and memory induced by the blockade of cholinergic transmission and abolishes the decrease of acetylcholine release induced by mecamylamine via the kappa receptor-mediated opioid neuronal system.     

Study on causes of the fires in rubble piles produced after the Great East Japan Earthquake, 2011

This paper seeks to determine the trigger of faint heat generation, which was one of the causes of fires in the piles of rubble produced after the 2011 Great East Japan Earthquake. The rubble piles consist of various combustible materials, such as wood, paper and plastics, as well as non‐combustible materials from destroyed buildings. Multiple rubble outdoor storage areas were temporarily set up in the disaster areas to dispose of rubble after it was piled up and separated. However, fires have been occurring in these storage areas since the summer of 2011. One cause of such fires is thought to be the heat generated by fermentation of microorganisms that easily proliferates within the piled up rubble, ultimately resulting in spontaneous ignition. In this study, we collected samples from rubble outdoor storage areas where fires have occurred. We then conducted thermal analyses to obtain basic data, and finally, we developed safety measures to prevent the recurrence of fire. The results revealed that the heat generated during fermentation of rotten tatami and wood chips most likely acts as a trigger causing the fires, given the adiabatic conditions are good. Copyright © 2014 John Wiley & Sons, Ltd.     

Minimal state space realizations in Jacobson normal form

We derive a procedure for a minimal state space realization of a rational transfer matrix over an arbitrary field. The procedure is based on the Smith-McMillan form and leads to a state transition matrix in Jacobson normal form.     

Study on spontaneous ignition of stored food waste to be used for recycling

Although stored at near room temperature, a large amount of stored industrial food waste or their recycled material gradually heats up and then ignites. To understand this phenomenon, soy sauce squeezing residue produced from the soy sauce brewing process and fish meal residue from processing fish were examined. We used a thermo gravimetric/differential thermal analysis system, a highly sensitive heat flux calorimeter (C80) and a spontaneous ignition tester to study their thermal properties. We applied Frank–Kamenetskii's thermal ignition theory to obtain the critical ignition temperature (Tc) and the relationship between Tc and the pile height. Copyright © 2012 John Wiley & Sons, Ltd.     

Formation of damascenone derived from glycosidically bound precursors in green tea infusions

Damascenone is well-known for its potent flavour with an extremely low odour threshold. Several glycosidically bound precursors of damascenone have been isolated from several plants, but little is known about their occurrences in green tea infusions. In this work, three major glycosidic precursors of damascenone, 9-O-β-d-glucopyranosyl-megastigma-6,7-dien-3,5,9-triol (1a), 9-O-β-d-glucopyranosyl-3-hydroxy-7,8-didehydro-β-ionol (2a), and 3-O-β-d-glucopyranosyl-3-hydroxy-7,8-didehydro-β-ionol (2b) were isolated and identified in green tea infusions, and the stereochemistries at C-3 and C-9 positions of aglycone parts of the three glycosidic precursors were determined as (3S, 9R)-1a, (3R, 9R)-2a, and (3R, 9R)-2b, respectively. Compounds 1a, 2a, and 2b as well as 3-O-β-d-glucopyranosyl-megastigma-6,7-dien-3,5,9-triol (1b) were hydrolysed to form damascenone in a model system with strong acidic conditions (pH 2.0) and at high temperature (90 °C). In contrast to hydrolysis of 2a and 2b, more damascenone was transformed from 1a and 1b. Furthermore, the β-d-glucosyl moiety at the C-3 position gave a higher dehydration rate from megastigma-6,7-dien-3,5,9-triol to 3-hydroxy-7,8-didehydro-β-ionol than compound 1a carrying the sugar residue at C-9 position. Interestingly, the four glycosidic precursors of damascenone were not hydrolysed to give damascenone under slightly acidic conditions (pH 5.4 and 120 °C for 10 min), but they could be transformed to damascenone in the presence of green tea infusions even under the equal conditions.     

Improved emulsifying properties of soy proteins by acylation with saturated fatty acids

Effects of acylation on emulsifying properties of soy proteins were investigated using a variety of saturated fatty acids. Beta conglycinin (7S), glycinin (11S), and acid-precipitated protein (APP) were acylated with activated fatty acid esters (6C–18C) to form covalent linkage between the carboxyl group of the fatty acid and the free amino groups of the protein. Reduction in the free amino groups of acylated 7S, 11S and APP resulted into the dissociation of the protein, indicating a structural change, as evidenced by the fluorescence spectra and the degree of modification. It was shown that the emulsifying activity (EAI) and emulsion stability (ES) of 7S and 11S were significantly improved (p < 0.05) upon acylation with all saturated fatty acids, whereas no change in EAI and ES for the acylated APP was observed upon attachment of short and long chain fatty acids. The fluorescence intensity was also remarkably affected by acylation showing significant changes in protein structure. Covalent attachment of fatty acids resulted into 1.4–2.2 and 1.1–1.8-fold increase in the oil binding capacity (OBC) of 7S and 11S respectively, however no changes in acylated APP. Acylated 7S showed 3.0–9.4-fold increase in the water binding capacity (WBC), with no change in acylated 11S, while acylated APP with longest chains showed low WBC. The surface hydrophobicity of 7S was significantly improved (p < 0.05) by acylation; no changes were observed in the acylated 11S. Furthermore, acylation decreased the surface hydrophobicity of APP. Thus, it was demonstrated that saturated fatty acids with adequate chain length are suitable candidates for the preparation of functional lipoproteins from soy proteins.     

Isolation and identification of compounds from the ethanolic extract of flowers of the tea (Camellia sinensis) plant and their contribution to the antioxidant capacity

While beneficial health properties of tea leaves have been extensively studied, less attention has been given to that of flowers of the tea (Camellia sinensis) plant. In this work, the ethanolic extract and its ethyl acetate-soluble fraction (EEA) from the tea flowers were found to possess the potent antioxidant activity using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay. The compounds present in EEA had comparatively strong DPPH scavenging activity and strongly contributed to the antioxidant activity of the tea flowers. From EEA, besides eight catechins, five flavonol glycosides were isolated and their structures were elucidated on the basis of mass spectrometry and nuclear magnetic resonance spectroscopy as myricetin 3-O-β-d-galactopyranoside, quercetin 3-O-β-d-galactopyranoside, kaempferol 3-O-β-d-galactopyranoside, kaempferol 3-O-β-d-glucopyranoside, and kaempferol 3-O-[α-l-rhamnopyranosyl-(1-6)-β-d-glucopyranoside]. In addition, epigallocatechin gallate and epicatechin gallate were found as the major active components responsible for the antioxidant activity of tea flowers through the use of a combination of preparative liquid chromatography separation and DPPH assay.