Interactions between arginine-rich histones and deoxyribonucleic acids. II. Circular dichroism

Circular dichroism (CD) was used to investigate the conformations of arginine-rich histones, H3 (III or f3) and H4 (IV or f2a1), and DNA in the complexes prepared by four different methods: (A) NaCl gradient dialysis with urea; (B) NaCl gradient dialysis without urea; (C) direct mixing in 2.5 x 10(-4) M EDTA, pH 8.0; and (D) direct mixing in 0.01 M sodium phosphate, pH 7.0. Using the CD spectrum of native chromatin as a criterion to judge the closeness of a complex to its native state, it was observed that a complex made by direct mixing at low ionic strength (methods C and D) is better than the ones made by NaCl gradient dialysis with or without urea (methods A and B). It is explained as a result of lack of ordered secondary structures in histones due to the presence of urea in method A or due to nonspecific aggregation in NaCl without urea (method B). Compared with all the earlier reports in literature on the CD of histone-DNA complexes, the CD spectra of arginine-rich histone-DNA complexes prepared by methods C and D are closest to that of native chromatin both in shape and in amplitude. These results imply (a) that arginine-rich histones play an important role in maintaining the conformation of chromatin and (b) that the binding of these two histones to DNA prepared by methods C and D are close to that in native chromatin. Noticeable variation in conformation of free and bound histone and histone-bound DNA has also been observed in histone H3 with one or two cysteine residues, and in reduced or oxidized state even when the complexes were prepared and examined in the same condition. CD spectra of arginine-rich histones in 0.01 M phosphates, pH 7.0, indicate the presence of alpha-helix which could be responsible for a favorable binding of the less basic regions of these histones to DNA under this condition as demonstrated by thermal denaturation (Yu, S. .S, Li H. J., and Shih, T. Y. (1976), Bio-chemistry, the preceding paper in this issue). To preserve or generate alpha-helical structures in histones seems to be a critical step in reconstituting good histone-DNA complexes.     

The p38 and NFκB signaling protein activation involved in glycitein protective effects on isoproterenol-treated H9c2 cardiomyoblast cells

Heart disease (HD) is greatly associated with gender and clinical evidence shows that increased serum norepinephrine levels are found in patients with HD. This study investigates the cardio-protective effect of glycitein, a selective estrogen receptor modulator (SERM) from soy bean extract, on H9c2 cardiomyoblast cells treated with isoproterenol (ISO, a norepinephrine analog). The image data and results from western blotting showed that ISO treatment was capable of inducing cellular apoptosis, especially the mitochondrial dependent pathway. Glycitein treatment could suppress mitochondrial pro-apoptotic proteins expression including caspase-9 and caspase-3 in H9c2 treated with ISO. In contrast, several survival proteins were expressed in H9c2 cells treated with glycitein, such as phosphor (p)-Akt, p-Bad and Akt. We confirmed that the protective role of glycitein was partially mediated through the expression of p-38 and NFκB proteins by adding several pathway inhibitors.     

Kefir peptides exhibit antidepressant-like activity in mice through the BDNF/TrkB pathway

Depression is a prevalent, stress-related mental disorder that can lead to serious psychiatric diseases with morbidity and high mortality. Although some functional fermented dairy drinks have promising anxiolytic and antidepressant effects, the mechanism is still not clear. To determine the antidepressant-like effect and the potential molecule mechanism of kefir peptides (KP), various behavioral tests, including the elevated plus maze test, open field test, forced swimming test, and tail suspension test, were used. Administration of 150 mg/kg KP in mice reduced the duration of immobility in the forced swimming test and tail suspension test, elevated the time spent in the open arm and center zone in the elevated plus maze test, and increased the total distance traveled, average speed, and time spent in the center zone in the open field test compared with the mock group. These results indicated that KP dramatically ameliorated the depression-like behaviors. Kefir peptides were further isolated and identified using high-performance liquid chromatography and liquid chromatography–tandem mass spectrometry, from which 3 peptides were identified and designated KFP-1, KFP-3, and KFP-5. Among these peptides, administration of KFP-3 (15 AA residues) remarkably decreased immobility time in the forced swimming test and increased mobility time in the tail suspension test. Therefore, KFP-3 may be the major active peptide with antidepressant activity in KP. Overexpression of brain-derived neurotrophic factor, phosphorylated tropomyosin receptor kinase B, and phosphorylated ERK1/2 protein levels could be detected in the hippocampus under KP administration. Therefore, we suggest that KP improves depressive-like behaviors by activating the brain-derived neurotrophic factor–phosphorylated tropomyosin receptor kinase B signaling pathway. Kefir peptides may serve as a new type of antidepressant dairy product and may provide potent antidepressant effects for clinical use.     

Induction of cell apoptosis in 3T3-L1 pre-adipocytes by flavonoids is associated with their antioxidant activity

Obesity is biologically characterized at the cellular level by an increase in the number and size of adipocytes differentiated from fibroblastic pre-adipocytes in adipose tissue. In this study, we focused on the relationship between the influence of flavonoids on cell population growth and their antioxidant activity. The results showed that the inhibition of flavonoids (naringenin, rutin, hesperidin, resveratrol, naringin and quercetin) on 3T3-L1 pre-adipocytes was 28.3, 8.1, 11.1, 33.2, 5.6 and 71.5%, respectively. In oxygen radical absorbance capacity (ORAC) assay, quercetin had the highest ORAC(ROO) value among the six flavonoids tested. Apoptosis assays showed that quercetin increased apoptotic cells in time- and dose-dependent manner. Treatment of cells with quercetin decreased the mitochondrial membrane potential in the courses of time and dose. The cell apoptosis/necrosis assay showed that quercetin increased the number of apoptotic cells, but not necrotic cells. Quercetin treatment of cells caused a significant time- and dose-dependent increase in the caspase-3 activity. Western analysis indicated that treatment of quercetin markedly down-regulated PARP and Bcl-2 proteins, and activated caspase-3, Bax, and Bak proteins. These results indicate that quercetin efficiently inhibits cell population growth and induction of apoptosis in 3T3-L1 pre-adipocytes.     

Antioxidant Activity of Mycelia from Aspergillus candidus

The antioxidant activity of mycelia extracts produced from the submerged cultures of Aspergillus candidus CCRC 31543 was investigated. Inhibition of peroxidation (IP%) of mycelia acetone extracts (MAE) in linoleic acid peroxidation was equal to that of BHA and significantly (p < 0.05) higher than that of α-tocopherol. As measured by the Rancimat method in lard, MAE showed marked antioxidant activity with an induction time of 8.4 h at a concentration of 200 μg/mL. MAE also exhibited strong scavenging effect on α,α-diphenyl-β-picrylhydrazyl radicals and marked reducing power. HPLC-DAD analysis suggested that MAE possessed the antioxidant components 3,3"-dihydroxyterphenyllin, 3-hydroxyterphenyllin, and candidusin B.     

Preventive effect of adding antioxidants on mutagenic compound formation in fumes of cooking oil

The preventive effect of various antioxidants on the formation of mutagenic compounds such as trans,trans‐2,4‐decadienal in degummed peanut oil (DPO) fumes was investigated. The mutagenicity of the DPO fumes was significantly reduced by antioxidants added before heating. The addition of antioxidants increased the smoke point and oxidative stability of DPO and decreased the yield of oil fumes and the amount of mutagens. Butylated hydroxyanisole and butylated hydroxytoluene were more effective than natural antioxidants in reducing the amount of four enal compounds in fumes from DPO. Thus edible cooking oil with a high smoke point, less fume and lower mutagenicity might be developed with an appropriate antioxidant. Copyright © 2004 Society of Chemical Industry     

Phenolic compounds: evidence for inhibitory effects against obesity and their underlying molecular signaling mechanisms

Phenolic compounds are widely present in the plant kingdom. Many epidemiological studies have indicated that consumption of some plant-derived foodstuffs with high phenolic content is associated with the prevention of some diseases and that these compounds may have similar properties to antioxidants, antimutagenic agents, antithrombotic agents, anti-inflammatory agents, anti-HIV-1, and anticancer agents. However, obesity is an important topic in the world of public health and preventive medicine. Relationships between body mass index, waist circumference, or waist-to-hip ratio and the risk of development of some diseases (such as heart disease, dyslipidemia, hypertension, non-alcoholic fatty liver disease, diabetes, kidney failure, cancer, stroke, osteoarthritis, and sleep apnea) have been observed. Evidence that phenolic compounds have beneficial effects in fighting obesity is increasingly being reported in the scientific literature. These in vitro and in vivo effects of phenolic compounds on the induction of pre-adipocytic and adipocytic apoptosis and inhibition of adipocytic lipid accumulation are considered in detail here. This review presents evidence of their inhibitory effects on obesity and their underlying molecular signaling mechanisms.     

Solvent fractionation of petroleum pitch for mesophase formation

Petroleum pitch (Ashland A240) has been subjected to thermal treatment and solvent fractionation to produce refined pitches to be evaluated as impregnants for C-C composites. The solvent fractions were obtained by sequential Soxhlet extraction with solvents such as hexane, benzene, and pyridine. Thermal treatment to 408 °C produced a mesophase pitch (≈50% mesophase); an appreciable portion of the mesophase was soluble in strong solvents. There were substantial differences in chemical composition and in pyrolysis behaviour of the fractions. As the depth of fraction increased, the pyrolysis yield and bloating increased, and the microstructure of the coke became finer until glassy microconstituents were formed in the deepest fractions.     

Myrosinase activity and total glucosinolate content of cruciferous vegetables,and some properties of cabbage myrosinase in Taiwan

The myrosinase activity and total glucosinolates of 10 different cruciferous vegetables and some properties of cabbage (Brassica oleracea L var capitata L) myrosinase were investigated. Radish, cabbage and broccoli showed higher myrosinase activity than other samples. No correlation (P > 0–05) was found between myrosinase activity and total glucosinolates of cruciferous vegetables tested. Myrosinase activity for white cabbage was higher than red cabbage. An optimal pH of myrosinase activity was observed at pH 8–0 for both white and red cabbages. The myrosinase extracted from cabbage was more stable in neutral or alkaline pH. The optimal temperature of myrosinase activity for both cabbages was about 60°C, but the myrosinase activity was destroyed after heating at 70°C for 30 min. The myrosinase activities of both white and red cabbages were activated by 10 mM and 5 mM ascorbic acid, respectively.