Coating of peanuts with edible whey protein film containing alpha-tocopherol and ascorbyl palmitate.

Physical properties of whey protein isolate (WPI) coating solution incorporating ascorbic palmitate (AP) and alpha-tocopherol (tocopherol) were characterized, and the antioxidant activity of dried WPI coatings against lipid oxidation in roasted peanuts were investigated. The AP and tocopherol were mixed into a 10% (w/w) WPI solution containing 6.7% glycerol. Process 1 (P1) blended an AP and tocopherol mixture directly into the WPI solution using a high-speed homogenizer. Process 2 (P2) used ethanol as a solvent for dissolving AP and tocopherol into the WPI solution. The viscosity and turbidity of the WPI coating solution showed the Newtonian fluid behavior, and 0.25% of critical concentration of AP in WPI solution rheology. After peanuts were coated with WPI solutions, color changes of peanuts were measured during 16 wk of storage at 25 degrees C, and the oxidation of peanuts was determined by hexanal analysis using solid-phase micro-extraction samplers and GC-MS. Regardless of the presence of antioxidants in the coating layer, the formation of hexanal from the oxidation of peanut lipids was reduced by WPI coatings, which indicates WPI coatings protected the peanuts from oxygen permeation and oxidation. However, the incorporation of antioxidants in the WPI coating layer did not show a significant difference in hexanal production from that of WPI coating treatment without incorporation of antioxidants.

Enhanced bio-mineralization by riboflavin photosensitization and its significance to detoxification of Benzo[a]pyrene.

In this study, (14)C-benzo[a]pyrene (BaP) was chosen as a model compound to investigate if photosensitization by riboflavin enhances the subsequent microbial mineralization of polycyclic aromatic hydrocarbons (PAHs) in natural aquatic environments. After photolysis, BaP showed an increased toxicity to human epithelial cell and natural microbial assemblage. However, BaP mineralization rate in a river water sample containing riboflavin is roughly twice of that without riboflavin after the 2-day incubation. Thus, the results imply that microbial assemblage can mineralize BaP photoproducts to carbon dioxide and a combination of riboflavin photosensitization and microbial degradation could lead to complete detoxification of PAHs.

5-HT2A receptor gene promoter polymorphism -1438A/G and bipolar disorder.

Genetic factors, such as the genes involved in the serotonin pathway, probably play an important role in the pathogenesis of bipolar disorder, and serotonin type 2A (5-HT2A) receptor gene promoter polymorphism -1438A/G has been reported. This study investigated the association between -1438A/G polymorphism of 5-HT2A receptor gene promoter and bipolar disorder in a Korean population. Using the polymerase chain reaction, -1438A/G polymorphism typed in 142 patients with bipolar disorder and in 148 normal control subjects. Differences in genotype distributions and allele frequencies of -1438A/G between patients with bipolar disorder and normal control subjects were tested for significance using the chi-squared test. There were significant differences in genotype distributions [chi2 = 9.697, degrees of freedom (df) = 2, P = 0.008] and allele frequencies (chi2 = 7.284, df = 1, P = 0.007) of -1438A/G between patients with bipolar disorder and normal control subjects. Although further studies are necessary, these results in a Korean population suggest that -1438A/G polymorphism of 5-HT2A receptor gene promoter may be causally related to the development of bipolar disorder.

Microbial ecotoxicity and mutagenicity of 1-hydroxypyrene and its photoproducts.

1-Hydroxypyrene (1-HP) is a carcinogenic and slightly water-soluble polycyclic aromatic hydrocarbon. Ecotoxicity and mutagenicity of 1-HP and its photoproducts, and the effect of Mn2+ and Cu2+ on their mutagenicity were measured with microbial assay in this study. The assay includes spread plate counting, direct counting, microbial mineralization of 14C-UL-D-glucose and Mutatox Test. At the concentration examined (0.8 microM), the photoproducts (after 1.5 h solar irradiation) of 1-HP inhibited microbial glucose mineralization activity (by 64%) after microbial assemblages of a local reservoir site were exposed for 1 day. However, heterotrophic bacteria were able to utilize 1-HP photoproducts as the growth substrates and increase viability counts by up to 4.75-folds. 1-HP exhibited positive response to Mutatox Test in both direct medium and S-9 medium, with the lowest observable effective concentration of 0.625 microM in the test with direct medium. After photolysis, 1-HP decreased its mutagenicity. Mn2+ (312.5 microM-5 mM) and Cu2+ (6.25-100 microM) themselves are not mutagenic. However, addition of the metal ions before or after photolysis modifies the light readings of 1-HP during the test. Therefore, presence of metal ions could affect the genotoxicity of 1-HP in aquatic environments, depending on timing of the addition.

Effect of photosensitizer riboflavin on the fate of 2,4,6-trinitrotoluene in a freshwater environment.

The effect of riboflavin (1 microM) on the fate of TNT (20 mg/l) in a natural water environment was studied. The relative contribution of photolysis, microbial assemblages and freshwater matrix to TNT degradation was examined. The rates, extent and products of TNT and riboflavin transformation were compared under different experimental conditions. It was found that riboflavin significantly enhanced the degradation of TNT in natural water environment. Thus it is a potentially useful photosensitizing agent for the treatment of TNT-contaminated surface water. Furthermore, in the presence of riboflavin, two new intermediates with max. absorption wavelength of 230 nm were found, demonstrating that transformation of TNT in the presence of riboflavin undergoes different pathways.

Neurotensin excitation of serotonergic neurons in the rat nucleus raphe magnus: ionic and molecular mechanisms.

To understand the cellular and molecular mechanisms by which neurotensin (NT) induces an analgesic effect in the nucleus raphe magnus (NRM), whole-cell patch-clamp recordings were performed to investigate the electrophysiological effects of NT on acutely dissociated NRM neurons. Two subtypes of neurons, primary serotonergic and secondary non-serotonergic cells, were identified from acutely isolated NRM neurons. During current-clamp recordings, NT depolarized NRM serotonergic neurons and evoked action potentials. Voltage-clamp recordings showed that NT excited serotonergic neurons by enhancing a voltage-insensitive and non-selective cationic conductance. Both SR48692, a selective antagonist of subtype 1 neurotensin receptor (NTR-1), and SR 142948A, a non-selective antagonist of NTR-1 and subtype 2 neurotensin receptor (NTR-2), failed to prevent neurotensin from exciting NRM serotonergic neurons. NT-evoked cationic current was inhibited by the intracellular administration of GDP-beta-S. NT failed to induce cationic currents after dialyzing serotonergic neurons with the anti-G(alphaq/11) antibody. Cellular Ca(2+) imaging study using fura-2 showed that NT induced the calcium release from the intracellular store. NT-evoked current was blocked after the internal perfusion of heparin, an IP(3) receptor antagonist, or BAPTA, a fast Ca(2+) chelator. It is concluded that neurotensin enhancement of the cationic conductance of NRM serotonergic neurons is mediated by a novel subtype of neurotensin receptors. The coupling mechanism via G(alphaq/11) proteins is likely to involve the generation of IP(3), and subsequent IP(3)-evoked Ca(2+) release from intracellular stores results in activating the non-selective cationic conductance.

Neurotensin excites periaqueductal gray neurons projecting to the rostral ventromedial medulla.

Microinjection of neurotensin into the midbrain periaqueductal gray (PAG) produces a potent and naloxone-insensitive analgesic effect. To test the hypothesis that neurotensin induces the analgesic effect by activating the PAG-rostral ventromedial medulla (RVM) descending antinociceptive pathway, PAG neurons that project to RVM (PAG-RVM) were identified by microinjecting DiI(C18), a retrograde tracing dye, into the rat RVM. Subsequently, fluorescently labeled PAG-RVM projection neurons were acutely dissociated and selected for whole cell patch-clamp recordings. During current-clamp recordings, neurotensin depolarized retrogradely labeled PAG-RVM neurons and evoked action potentials. Voltage-clamp recordings indicated that neurotensin excited PAG-RVM neurons by opening the voltage-insensitive and nonselective cation channels. Both SR 48692, a selective NTR-1 antagonist, and SR 142948A, a nonselective antagonist of NTR-1 and NTR-2, failed to prevent neurotensin from exciting PAG-RVM neurons. Neurotensin failed to evoke cationic currents after internally perfusing PAG-RVM projection neurons with GDP-beta-S or anti-G(alpha q/11) antiserum. Cellular Ca(2+) fluorescence measurement using fura-2 indicated that neurotensin rapidly induced Ca(2+) release from intracellular stores of PAG-RVM neurons. Neurotensin-evoked cationic currents were blocked by heparin, an IP(3) receptor antagonist, and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), a fast chelator of Ca(2+). These results suggest that by activating a novel subtype of neurotensin receptors, neurotensin depolarizes and excites PAG-RVM projection neurons through enhancing Ca(2+)-dependent nonselective cationic conductance. The coupling mechanism via G(alpha q/11) proteins is likely to involve the production of IP(3), and subsequent IP(3)-evoked Ca(2+) release leads to the opening of nonselective cation channels.

UVA-Induced DNA single-strand cleavage by 1-hydroxypyrene and formation of covalent adducts between DNA and 1-hydroxypyrene.

1-Hydroxypyrene (HOP), a metabolite found in the urine of humans and laboratory animals exposed to polycyclic aromatic hydrocarbons (PAHs), is known to be both acutely toxic and genotoxic. It has been widely used as a biomarker for studying PAH exposure. In this research, we have found that, upon UVA irradiation, HOP causes DNA single-strand cleavages and forms HOP-DNA covalent adducts. The UVA-induced cleavage of supercoiled plasmid PhiX174 DNA is dependent upon both HOP concentration and UVA dosage. A longer irradiation time or higher HOP concentration induces more DNA cleavage. Results of the photocleavage experiments carried out in the presence of reactive oxygen species scavengers, histidine, sodium azide, mannitol, SOD, and desferal indicate that both the superoxide free radical and singlet oxygen are likely involved in causing DNA single-strand cleavage. The photocleavage is inhibited by the presence of an excited singlet-state quencher, KI, indicating that it is an excited-state reaction. Along with light-induced DNA cleavage, HOP also forms DNA covalent adducts while being degraded upon light irradiation. Light-induced degradation of 20 microM HOP follows first-order reaction kinetics in a 10% methanolic buffer (10 mM phosphate) solution in the absence or presence of 40 microM calf thymus DNA, with degradation half-lives of 20 or 15 min, respectively. The shorter degradation half-life in the presence of DNA is due to the formation of the HOP-DNA covalent adduct. The formation of the HOP-DNA covalent adduct is evidenced by comparing the UV-vis absorption and fluorescence emission spectra of the pure HOP with those of the HOP-DNA adduct. The covalent HOP-DNA adduct produced due to irradiation was purified by either extensive dialysis (3 x 500 mL buffer solutions), phenol and chloroform extraction followed by ethanol precipitation, or chloroform extraction alone. The isolated HOP-DNA adduct has an absorption peak at 353 nm, which is 8 nm red-shifted compared to that of free HOP. The fluorescence emission for HOP-DNA is at least 70 times weaker than that for free HOP in solution. In summary, the findings with HOP reveal that, in addition to metabolic activation that eventually leads to the formation of alkylated DNA adducts or other forms of DNA damage, HOP may be activated by light to produce DNA single-strand cleavage and covalent DNA adducts. These DNA lesions can be sources of toxicity.

Kainic acid-induced neurotrophic activities in developing cortical neurons.

Using primary cultured cortical neurons from embryonic rat brains, we elucidated an alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)/kainic acid (KA) receptor-mediated neuroprotective mechanism through actions of nerve growth factor (NGF) in developing neurons. Neurotoxicity of KA in early days in vitro neurons was quite low compared with the mature neurons. However, pretreatment with anti-NGF antibody or TrkA inhibitor AG-879 profoundly raised KA toxicity. Furthermore, KA stimulation resulted in an increase of TrkA expression and phosphorylation, which was blocked not only by the AMPA/KA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione and AG-879, but also by the phospholipase C inhibitor U73122 and the intracellular calcium chelator BAPTA. A study of polyphosphoinositide turnover showed that KA-stimulated phospholipase C (PLC) activity was directly triggered by the AMPA/KA receptor activity, but not by the activity of TrkA or other excitatory amino acid receptor subtypes. Sources of KA-increased intracellular calcium levels were contributed by both extracellular calcium influx and intracellular calcium release and were partially sensitive to guanosine 5'-O-(2-thiodiphosphate). These results indicate that in developing cortical neurons, activation of AMPA/KA receptors by KA may induce expression, followed by activation of TrkA via PLC signaling and intracellular calcium elevation and hence increase reception of NGF on KA-challenged neurons. A G protein-coupled AMPA/KA receptor may be involved in these metabotropic events for neuronal protection.

The fate of hydrogen peroxide as an oxygen source for bioremediation activities within saturated aquifer systems.

In situ bioremediation is an innovative technique for the remediation of contaminated aquifers that involves the use of microorganisms to remediate soils and groundwaters polluted by hazardous substances. During its application, this process may require the addition of nutrients and/or electron acceptors to stimulate appropriate biological activity. Hydrogen peroxide has been commonly used as an oxygen source because of the limited concentrations of oxygen that can be transferred into the groundwater using above-ground aeration followed by reinjection of the oxygenated groundwater into the aquifer or subsurface air sparging of the aquifer. Because of several potential interactions of H2O2 with various aquifer material constituents, its decomposition may be too rapid, making effective introduction of the H2O2 into targeted treatment zones extremely difficult and costly. Therefore, a bench-scale study was conducted to determine the fate of H2O2 within subsurface aquifer environments. The purpose of this investigation was to identify those aquifer constituents, both biotic and abiotic, that are most active in controlling the fate of H2O2. The decomposition rates of H2O2 were determined using both equilibrated water samples and soil slurries. Results showed H2O2 decomposition to be effected by several commonly found inorganic soil components; however, biologically mediated catalytic reactions were determined to be the most substantial.

gas7: A gene expressed preferentially in growth-arrested fibroblasts and terminally differentiated Purkinje neurons affects neurite formation.

Growth arrest-specific (gas) genes are expressed preferentially in cells that enter a quiescent state. gas7, which we identified in serum-starved murine fibroblasts, is reported here to be expressed in vivo selectively in neuronal cells of the mature cerebral cortex, hippocampus, and cerebellum. gas7 transcripts encode a 48-kDa protein containing a structural domain that resembles sequences of OCT2, a POU transcription factor implicated in neuronal development, and synapsins, which have a role in modulating neurotransmitter release. Using in situ hybridization and immunocytochemical analysis, we show that GAS7 expression occurs prominently in cerebellar Purkinje cells and that inhibition of production in terminally differentiating cultures of embryonic murine cerebellum impedes neurite outgrowth from maturing Purkinje cells. Conversely, GAS7 overexpression in undifferentiated neuroblastoma cell cultures dramatically promotes neurite-like outgrowth. Collectively, our results provide evidence for an association between expression of this gas gene and neuronal development.

Neuritogenesis, not receptor expression, of NG108-15 cells can be modulated by monosialoganglioside GM1.

In this study, involvement of gangliosides in neurite outgrowth and receptor expression of the neuroblastoma X glioma hybrid NG108-15 cloned cells was investigated. Monosialoganglioside GM1 (100 microM) and disialoganglioside GD1a (100 microM) were applied to the culture medium at different concentrations of fetal bovine serum, 1-10%, with or without addition of dibutyryl adenosine 3',5'-cyclic monophosphate (500 microM). In some experiments, 5 mg/ml of cholera toxin B was added to the media to block endogenous GM1. The results indicated that GM1 had an influence on cell proliferation and neuritogenesis but did not induce muscarinic receptor expression of NG108-15 cells.