Fermented date residue extract mix containing gamma-aminobutyric acid augments the immune function of mouse splenocytes.

An extract of date (fruit of a palm tree) residue plus food-grade glutamate, acetic acid, and yeast extract (date residue extract mix, DREM) has been successfully fermented with using Lactobacillus brevis JCM 1059T to produce gamma-aminobutyric acid (GABA). Here, mouse splenocytes were found to be viable when supplemented with DREM and fermented DREM containing GABA (fDREM). The addition of DREM and fDREM resulted in the secretion of tumor necrosis factor (TNF)-α from the splenocytes, fDREM being more effective than DREM. The TNF-α secretion with DREM was elevated by exogenous addition of GABA and that with fDREM was in part mediated via A-type GABA receptors. Contrary to general understanding of the suppressive effects of GABA on various biological functions, our findings suggest that GABA-containing fDREM arguments the immune function as a food and pharmaceutical material.

Expression of two glutamate decarboxylase genes in Lactobacillus brevis during gamma-aminobutyric acid production with date residue extract.

Gamma-aminobutyric acid (GABA) is produced by Lactobacillus brevis using date residue fermentation. In this study, the GABA production method was improved, for which L. brevis strain JCM 1059T was the most efficient among the four L. brevis strains examined. This was presumably due to a difference in the expression level of the gene encoding glutamate decarboxylase that catalyzes GABA synthesis.Abbreviation: GABA: gamma-aminobutyric acid.

Metabolism of 3-[5'-deoxy-5'-(dimethylarsinoyl)-ß-ribofuranosyloxy]-2-hydroxypropylene glycol in an artificial digestive system.

Seaweeds contain large amounts of organoarsenic compounds, mostly arsenosugars (AsSug) and arsenolipids (AsLipid). AsSug is mainly metabolized into dimethylarsinic acid (DMA V ) in humans. However, this metabolic process is not well understood. We investigated the metabolism of an AsSug, 3-[5'-deoxy-5'-(dimethylarsinoyl)-ß-ribofuranosyloxy]-2-hydroxypropylene glycol (AsSug328), in the gastrointestinal tract using an in vitro artificial gastrointestinal digestion system. AsSug328 was incubated with gastric juice for 4 h, with bile-pancreatic juice for 0.5 h, and finally with enteric bacteria solution for 24 h. The conversion of arsenic compounds after artificial digestion was analyzed by HPLC-ICP-MS and HPLC-ESI-Q-TOF-MS. Our results show that artificial gastrointestinal digestion converted AsSug328 into thio-AsSug328. However, no formation of DMA V was detected. Under the artificial digestion system, the 5-deoxyribofuranose structure of AsSug was maintained. Therefore, AsSug should be absorbed in the intestinal tract after its sugar moiety is partially decomposed. They are then possibly metabolized to DMA V in the liver and subsequently excreted through urine.

Effect of Polymer Phase Transition Behavior on Temperature-Responsive Polymer-Modified Liposomes for siRNA Transfection.

Small interfering RNAs (siRNAs) have been attracting significant attention owing to their gene silencing properties, which can be utilized to treat intractable diseases. In this study, two temperature-responsive liposomal siRNA carriers were prepared by modifying liposomes with different polymers-poly(N-isopropylacrylamide-co-N,N-dimethylaminopropyl acrylamide) (P(NIPAAm-co-DMAPAAm)) and poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) P(NIPAAm-co-DMAAm). The phase transition of P(NIPAAm-co-DMAPAAm) was sharper than that of P(NIPAAm-co-DMAAm), which is attributed to the lower co-monomer content. The temperature dependent fixed aqueous layer thickness (FALT) of the prepared liposomes indicated that modifying liposomes with P(NIPAAm-co-DMAPAAm) led to a significant change in the thickness of the fixed aqueous monolayer between 37 °C and 42 °C; while P(NIPAAm-co-DMAAm) modification led to FALT changes over a broader temperature range. The temperature-responsive liposomes exhibited cellular uptake at 42 °C, but were not taken up by cells at 37 °C. This is likely because the thermoresponsive hydrophilic/hydrophobic changes at the liposome surface induced temperature-responsive cellular uptake. Additionally, siRNA transfection of cells for the prevention of luciferase and vascular endothelial growth factor (VEGF) expression was modulated by external temperature changes. P(NIPAAm-co-DMAPAAm) modified liposomes in particular exhibited effective siRNA transfection properties with low cytotoxicity compared with P(NIPAAm-co-DMAAm) modified analogues. These results indicated that the prepared temperature-responsive liposomes could be used as effective siRNA carriers whose transfection properties can be modulated by temperature.

Gamma-aminobutyric acid fermentation with date residue by a lactic acid bacterium, Lactobacillus brevis.

Dates are commercially consumed as semi-dried fruit or processed into juice and puree for further food production. However, the date residue after juice and puree production is not used, although it appears to be nutrient enriched. Here, date residue was fermented by a lactic acid bacterium, Lactobacillus brevis, which has been generally recognized as safe. Through degradation of sodium glutamate added to the residue during the fermentation, γ-aminobutyric acid (GABA), which reduces neuronal excitability, was produced at the conversion rate of 80-90% from glutamate. In order to achieve this GABA production level, pretreatment of the date residue with carbohydrate-degrading enzymes, i.e., cellulase and pectinase, was necessary. All ingredients used for this GABA fermentation were known as being edible. These results provide us with a solution for the increasing commercial demand for GABA in food industry with the use of date residue that has been often discarded.

The systematic structure-activity relationship to predict how flavones bind to human androgen receptor for their antagonistic activity.

Although flavones act as potent androgen receptor (AR) antagonists, it remains unclear how flavones interact with AR. The aim of this in silico study was to investigate the molecular recognition processes of newly synthesized 5,4'-difluoroflavone with the highest activity (IC50 value=0.19 µM) in the AR-ligand binding domain (AR-LBD). The results demonstrated that at its 4'-position of 5,4'-difluoroflavone the substituents may face Arg752 and that in AR-LBD, the submolecular bulk of substituents is unfavorable for AR antagonists and the negative electrostatic interaction site prefers the stronger hydrogen bond capability of substituents of AR antagonists. The prediction model is a valuable tool for designing a novel AR antagonist.

Facilitation of reflex swallowing from the pharynx and larynx.

To evaluate the cooperative effect of afferent signals from the pharynx and larynx on reflex swallowing, the interactive effect of afferent signals from the pharyngeal branch of the glossopharyngeal nerve (GPN-ph) and superior laryngeal nerve (SLN) was analyzed in detail in urethane-anesthetized rats. The electromyographic activity of the mylohyoid muscle was recorded as an indicator of swallowing activity. The onset latency of reflex swallowing was measured to evaluate the effects of electrical stimulation of these nerves, and found to become shorter following an increase in the GPN-ph and/or SLN stimulus frequency. During simultaneous electrical stimulation of the GPN-ph and SLN (frequency: 5-10 Hz, intensity: 30 muA, duration: 1.0 ms for each), the onset latency of reflex swallowing became shorter than that for stimulation of each nerve independently. The present findings suggest that spatiotemporal summation of afferent signals from the GPN-ph and SLN results in an increase of motoneuronal activity in the medullary swallowing center, thus enhancing reflex swallowing.

Attenuation of naloxone-induced Vc pERK hyper-expression following capsaicin stimulation of the face in aged rat.

In order to clarify the effect of age-related change in trigeminal nociception, phosphorylation of extracellular signal-regulated kinase (pERK) in trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal cord neurons were studied in the aged rats following subcutaneous capsaicin injection into the whisker pad. A large number of pERK-LI cells was expressed in the superficial laminae of Vc and upper cervical spinal cord in adult and aged rats following subcutaneous capsaicin injection into the whisker pad region. The number of pERK-LI cells was largest at about 2.0mm caudal from the obex and gradually decreased in their numbers in more rostral and caudal sections. The rostro-caudal distribution profile of pERK-LI cells expressed after subcutaneous capsaicin injection into whisker pad was similar in adult and aged rats. The number of pERK-LI cells was slightly, but not significantly larger in aged rats compared with that of adults. Pretreatment with naloxone significantly increased the number of capsaicin-induced pERK-LI cells in adult rats but not in aged rats. The present findings suggest that the descending modulation system impaired with advancing age, resulting in the abnormal pain sensation in aged rats.