Showing papers in "Bioscience, Biotechnology, and Biochemistry in 2003"
TL;DR: This review is an outline of genetic knowledge about bacterial PAH catabolism from both Gram-negative bacteria other than Pseudomonas species and Gram-positive bacteria, and the information about these genes is expanding.
Abstract: Polycyclic aromatic hydrocarbons (PAHs), which consist of two or more fused aromatic rings, are widespread in the environment and persist over long periods of time. The decontamination of a PAH-polluted environment is of importance because some PAHs are toxic, mutagenic, and carcinogenic and therefore are health hazards. As part of the efforts to establish remediation processes, the use of aerobic bacteria has been extensively studied, and both enzymologic and genetic studies are underway for the purpose of effective biodegradation. In the last two decades, one highly conserved group of PAH-catabolic genes from Pseudomonas species, called the nah-like genes, has been well investigated, and much has been found, including the structure-function relationships and the evolutionary trails of the catabolic enzymes. However, recently, PAH-catabolic genes, which are evolutionarily different from the nah-like genes, have been characterized from both Gram-negative bacteria other than Pseudomonas species and Gram-positive bacteria, and the information about these genes is expanding. This review is an outline of genetic knowledge about bacterial PAH catabolism.
407 citations
TL;DR: The features of the H2O2-generating property of green tea, black tea, and coffee were in good agreement with that of phenolic compounds, suggesting that polyphenols are responsible for the generation of H2 O2 in beverages.
Abstract: To investigate the ability of the production of H2O2 by polyphenols, we incubated various phenolic compounds and natural polyphenols under a quasi-physiological pH and temperature (pH 7.4, 37°C), and then measured the formation of H2O2 by the ferrous ion oxidation-xylenol orange assay. Pyrocatechol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, and polyphenols such as catechins yielded a significant amount of H2O2. We also examined the effects of a metal chelator, pH, and O2 on the H2O2-generating property, and the generation of H2O2 by the polyphenol-rich beverages, green tea, black tea, and coffee, was determined. The features of the H2O2-generating property of green tea, black tea, and coffee were in good agreement with that of phenolic compounds, suggesting that polyphenols are responsible for the generation of H2O2 in beverages. From the results, the possible significances of the H2O2-generating property of polyphenols for biological systems are discussed.
268 citations
TL;DR: To confirm the absorption of proanthocyanidin (PA) into the human body, four healthy adults were administered 2.0 g of PA-rich grape seed extract (GSE) and procyanidin B1 [epicatechin-(4β→8)-catechin] was detected in human serum 2 h after intake.
Abstract: To confirm the absorption of proanthocyanidin (PA) into the human body, four healthy adults were administered 2.0 g of PA-rich grape seed extract (GSE). Blood were drawn before intake and 2 h after intake. Through the enzymatic treatment of sulfatase and β-glucuronidase, blood samples were analyzed by HPLC coupled with mass-spectrometry (LC/MS). Procyanidin B1 [epicatechin-(4β→8)-catechin] was detected in human serum 2 h after intake. Its concentration was 10.6±2.5 nmol/l.
228 citations
TL;DR: It is suggested that FOS supplementation changes the intestinal environment of microflora, and leads to upregulation of IgA secretion in CD4+ PP cells in intestinal mucosa, and to suppression of the systemic immune response to type 2 helper T (Th2) dominant.
Abstract: Probiotic supplements induce immunological responses in the host, and dietary fructooligosaccharides (FOS) stimulate the growth of selected intestinal microflora. In this study we investigated the immunological influences of orally administrated FOS. BALB/c mice were oral administered 0-7.5% FOS for 6 weeks, and the intestinal mucosal immune responses were measured. In the 2.5%-FOS group, fecal IgA was significantly increased. IgA secretion by Peyer's patch (PP) cells was upregulated in a dose-dependent way in response to FOS and CD4+ T cells from PP showed a dose-dependent increase in production of interferon-γ and interleukin (IL) 10, and a high response in production of IL-5 and IL-6. In contrast, FOS suppressed serum IgG1. Our findings suggest that FOS supplementation changes the intestinal environment of microflora, and leads to upregulation of IgA secretion in CD4+ PP cells in intestinal mucosa, and to suppression of the systemic immune response to type 2 helper T (Th2) dominant.
220 citations
TL;DR: The GG cells significantly lowered the blood hemoglobin A1C (HbA1C) level and improved glucose tolerance in n-STZ rats and in the GG group, the serum insulin level at 30 min after glucose loading was significantly higher than in the control group (p<0.05).
Abstract: Neonatally streptozotocin-induced diabetic (n-STZ) rats were given food containing Lactobacillus GG cells (GG) or a control diet (control), from 9 to 18 weeks of age. The GG cells significantly lowered the blood hemoglobin A(1C) (HbA(1C)) level and improved glucose tolerance in n-STZ rats (p<0.05). In the GG group, the serum insulin level at 30 min after glucose loading was significantly higher than in the control group (p<0.05).
217 citations
TL;DR: The structure-activity relationships among five esculetin analogs suggest that hydroxyl groups at the C6 and C7 positions of the coumarin skeleton played an important role in the expression of tyrosinase inhibitory activity.
Abstract: A tyrosinase inhibitor was isolated from the seeds of Euphorbia lathyris L. by bioassay-guided fractionation and purification, using silica gel column chromatography. It was identified as esculetin by comparing its physical properties and spectral data with those of an authentic sample. The IC50 value of esculetin in the mushroom tyrosinase activity test was 43 μM. The kinetic study indicates that esculetin exhibited competitive inhibition against the oxidation of 3-(3,4-dihydroxyphenyl)-alanine by mushroom tyrosinase. The structure-activity relationships among five esculetin analogs suggest that hydroxyl groups at the C6 and C7 positions of the coumarin skeleton played an important role in the expression of tyrosinase inhibitory activity.
206 citations
TL;DR: Dioscin and its aglycone, diosgenin, both suppressed the time-dependent increase of blood triacylglycerol level when orally injected with corn oil to mice, suggesting their inhibitory potential against fat absorption.
Abstract: In the process of screening for pancreatic lipase inhibitors, which could be used as an anti-obesity measure, the methanol extract of Dioscorea nipponica Makino powder (DP) appeared to have potent inhibitory activity against porcine pancreatic lipase with an IC50 value of 5-10 μg/ml, where the enzyme activity was assayed by using 4-methylumbelliferyl oleate as a substrate. Further purification of active components present in the herb generated dioscin that belongs to the saponin family. Dioscin and its aglycone, diosgenin, both suppressed the time-dependent increase of blood triacylglycerol level when orally injected with corn oil to mice, suggesting their inhibitory potential against fat absorption. Sprague-Dawley rats fed on a high-fat diet containing 5% Dioscorea nipponica Makino and 40% beef tallow gained significantly less body weight and adipose tissue than control animals fed on a high-fat diet alone during an 8-week experimental period (P<0.05).
201 citations
TL;DR: A methanol extract from the flower heads of Chrysanthemum morifolium showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-Furyl)acrylamide (furylfuramide).
Abstract: A methanol extract from the flower heads of Chrysanthemum morifolium showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract was re-extracted with hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction showed a suppressive effect. Suppressive compounds in the ethyl acetate fraction were isolated by silica gel column chromatography and identified as the flavonoids acacetin (1), apigenin (2), luteolin (3), and quercetin (4) by EI-MS, IR, and (1)H and 13C NMR spectroscopy. Compounds 1-4 suppressed the furylfuramide-induced SOS response in the umu test. Compounds 1-4 suppressed 60.2, 75.7, 90.0, and 66.6% of the SOS-inducing activity at a concentration of 0.70 micromol/ml. The ID50 (50% inhibitory dose) values of 1-4 were 0.62, 0.55, 0.44, and 0.59 micromol/ml. These compounds had the suppressive effects on umu gene expression of the SOS response against other mutagens, 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which do not require liver-metabolizing enzymes. These compounds also showed the suppression of SOS-inducing activity against the other mutagens aflatoxin B1 (AfB1) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver-metabolizing enzymes, and UV irradiation. In addition to the antimutagenic activities of these compounds against furylfuramide, Trp-P-1 and activated Trp-P-1 were also assayed by the Ames test using S. typhimurium TA100.
191 citations
TL;DR: The inhibitory activity of Trp-Leu was completely preserved after a treatment with pepsin, chymotrypsin or trypsin, and even after successive digestion by these gastrointestinal proteases, the activity remained at 29% of the original value.
Abstract: Angiotensin I-converting enzyme (ACE) inhibitory activity was observed in a tofuyo (fermented soybean food) extract with an IC50 value of 1.77 mg/ml. Two ACE inhibitors were isolated to homogeneity from the extract by adsorption and gel filtration column chromatography, and by reverse-phase high-performance liquid chromatography (HPLC). The purified substances reacted with 2,4,6-trinitrobenzensulfonic acid sodium salt. The amino acid sequences of these inhibitors determined by Edman degradation were Ile-Phe-Leu (IC50, 44.8 μM) and Trp-Leu (IC50, 29.9 μM). The Ile-Phe-Leu sequence is found in the α- and β-subunits of β-conglycinin, while the Trp-Leu sequence is in the B-, B1A- and BX-subunits of glycinin from soybean. Both of the peptides are non-competitive inhibitors. The inhibitory activity of Trp-Leu was completely preserved after a treatment with pepsin, chymotrypsin or trypsin. Even after successive digestion by these gastrointestinal proteases, the activity remained at 29% of the original value.
179 citations
TL;DR: This polyphenoloxidase found in the cell extract of Streptomyces lavendulae REN-7 is a thermostable laccase that retained its original activity after 20 min of incubation at even 70°C.
Abstract: We found a polyphenoloxidase (PPO) in the cell extract of Streptomyces lavendulae REN-7. About 0.8 mg of purified PPO was obtained from 200 g of the mycelia with a yield of 9.0%. REN-7-PPO showed broad substrate specificity toward various aromatic compounds. Moreover, this enzyme was capable of oxidation of syringaldazine, which is a specific substrate for laccase. Interestingly, REN-7-PPO retained its original activity after 20 min of incubation at even 70°C. The gene encoding the PPO was cloned. Four copper-binding sites characteristics of laccases were contained in the deduced amino acid sequence. We constructed a high-level expression system of this gene in Escherichia coli. The properties of the recombinant enzyme were identical that of wild-type. In conclusion, this PPO is a thermostable laccase.
174 citations
TL;DR: N-terminal amino acid sequencing, mass spectral analysis of the purified bacteriocin, and genetic analysis using nisin-specific primers showed that the bacteriOCin was a new natural nisin variant, termed nisin Q.
Abstract: Lactococcus lactis 61-14 isolated from river water produced a bacteriocin active against a wide range of Gram-positive bacteria. N-terminal amino acid sequencing, mass spectral analysis of the purified bacteriocin, and genetic analysis using nisin-specific primers showed that the bacteriocin was a new natural nisin variant, termed nisin Q. Nisin Q and nisin A differ in four amino acids in the mature peptide and two in the leader sequence.
TL;DR: The elevation of systolic blood pressure in SHRs was significantly retarded in the GABA-tempeh group as well as that with authentic GABA when compared with the controls, and the effect lasted for two months of the feeding period.
Abstract: GABA-enriched tempeh-like fermented soybean (GABA-tempeh) was supplemented to the AIN-76 diet and fed for 2 months to spontaneously hypertensive rats (SHRs), an animal model of spontaneously developed hypertension, to compare the antihypertensive activity with that of authentic GABA. The elevation of systolic blood pressure in SHRs was significantly retarded in the GABA-tempeh group as well as that with authentic GABA when compared with the controls, and the effect lasted for two months of the feeding period. The blood urea nitrogen level tended to be higher in the control group than in the GABA-supplemented groups. On the other hand, no effect was apparent on the plasma levels of cholesterol, triacylglycerol and glucose, or on the urinary excretion of Na and K.
TL;DR: A cultivation procedure for the preparation of a new tempeh-like fermented soybean containing a high level of γ-aminobutyric acid was developed and showed that all of R. oligosporus and R. oryzae examined accumulated GABA in the anaerobically fermented soybeans showed the highest content of GABA.
Abstract: A cultivation procedure for the preparation of a new tempeh-like fermented soybean containing a high level of gamma-aminobutyric acid was developed. Steamed soybeans were incubated aerobically with Rhizopus microsporus var. oligosporus IFO 8631 for 20 h, and then anaerobically incubated for 5 h by replacement of the atmosphere with nitrogen. The GABA content in the aerobically fermented soybeans was about 30 mg per 100 g dry fermented soybeans, while the anaerobically cultivation was about 370 mg/100 g dry fermented soybeans. The incubation with several strains of Rhizopus species showed that all of R. microsporus var. oligosporus and R. oryzae examined accumulated GABA in the anaerobically fermented soybeans. In particular, R. microsporus var. oligosporus IFO 32002 and IFO 32003 showed the highest content of GABA (1,740 mg/100 g dry fermented soybeans and 1,500 mg/100 g dry fermented soybeans, respectively). Moreover, the free protein amino acids increased greatly in the fermented soybeans during the anaerobic cultivation.
TL;DR: Dietary phenolic acids showed diversified characteristics in their intestinal absorption, indicating that the transepithelial transport of CA was via the monocarboxylic acid transporter (MCT), and that the transport rate of GA was about 100 times lower than that of CA, suggesting the transport of GA to be via the paracellular pathway.
Abstract: The transepithelial transport of such common dietary phenolic acids as p-coumaric acid (CA) and gallic acid (GA) across Caco-2 cell monolayers was examined. CA transport was dependent on pH, and in a vectorial manner in the apical-basolateral direction. The permeation was concentration-dependent and saturable, the Michaelis constant and maximum velocity being 17.5 mM and 82.7 nmol min-1 (mg of protein)-1, respectively. Benzoic acid and acetic acid inhibited the permeation of CA. These results indicate that the transepithelial transport of CA was via the monocarboxylic acid transporter (MCT). On the other hand, the permeation of GA was not in a polarized manner, was independent of pH and linearly increased with increasing concentration of GA. The transport rate of GA was about 100 times lower than that of CA, suggesting the transepithelial transport of GA to be via the paracellular pathway. Dietary phenolic acids thus showed diversified characteristics in their intestinal absorption.
TL;DR: The DNA damage in lymphocytes induced by the flavonoids in the model system might have been due to their stimulation of oxidative stress in the lymphocytes, which resulted in the decrease of cell membrane protein thiols, increase of lipid peroxidation in cell membrane and in the influence of the antioxidative enzyme activities.
Abstract: The pro-oxidative properties of the four flavonoids, quercetin, morin, naringenin and hesperetin, in human lymphocyte system were investigated. Naringenin and hesperetin accelerated the oxidation of deoxyribose induced by Fe(3+)/H(2)O(2) in a concentration range of 0-200 microM, but quercetin and morin decreased it when the concentration was greater than 100 microM. The generation of hydrogen peroxide and the superoxide anion and the production of TBARS in lymphocytes were increased with increasing concentration of a flavonoid. Cell membrane protein thiols of the lymphocytes decreased when treated with the four flavonoids. Quercetin and hesperetin had no significant effect (p>0.05) on the activity of glutathione reductase, but morin and naringenin could inhibit the activity of the enzyme at a concentration of 200 microM, when compared to the control group. The glutathione S-transferase activity was slightly decreased by treatment with each of the four flavonoids only at a concentration of 200 microM. Therefore, the DNA damage in lymphocytes induced by the flavonoids in the model system might have been due to their stimulation of oxidative stress in the lymphocytes, which resulted in the decrease of cell membrane protein thiols, increase of lipid peroxidation in cell membrane and in the influence of the antioxidative enzyme activities.
TL;DR: In this paper, the authors found that rebeccamycin is constructed by oxidative decarboxylation of chromopyrrolic acid generated from two molecules of tryptophan by coupling and that the oxidation state at the C-7 position depends on the additional enzymes(s) encoded by the biosynthetic genes.
Abstract: The biosynthetic gene cluster for rebeccamycin, an indolocarbazole antibiotic, from Lechevalieria aerocolonigenes ATCC 39243 has 11 ORFs. To clarify their functions, mutants with rebG, rebD, rebC, rebP, rebM, rebR, rebH, rebT, or orfD2 disrupted were constructed, and the gene products were examined. rebP disruptants produced 11,11'-dichlorochromopyrrolic acid, found to be a biosynthetic intermediate by a bioconversion experiment. Other genes encoded N-glycosyltransferase (rebG), monooxygenase (rebC), methyltransferase (rebM), a transcriptional activator (rebR), and halogenase (rebH). rebT disruptants produced rebeccamycin as much as the wild strain, so rebT was probably not involved in rebeccamycin production. Biosynthetic genes of staurosporine, an another indolocarbazole antibiotic, were cloned from Streptomyces sp. TP-A0274. staO, staD, and staP were similar to rebO, rebD, and rebP, respectively, all of which are responsible for indolocarbazole biosynthesis, But a rebC homolog, encoding a putative enzyme oxidizing the C-7 site of pyrrole rings, was not found in the staurosporine biosynthetic gene cluster. These results suggest that indolocarbazole is constructed by oxidative decarboxylation of chromopyrrolic acid (11,11'-dichlorochromopyrrolic acid in rebeccamycin) generated from two molecules of tryptophan by coupling and that the oxidation state at the C-7 position depends on the additional enzyme(s) encoded by the biosynthetic genes.
TL;DR: Celastrol was found to induce apoptosis, and the rank order of the potency of celastrol and its derivatives to induce internucleosomal DNA fragmentation was found the other derivatives=vehicle control, indicating that the apoptosis-inducing activities of cela derivatives correspond to their inhibitory activities on topoisomerase II.
Abstract: Celastrol, which is a triterpene purified from Celastraceae plants, has anticancer and anti-inflammatory activities. In this study we investigated to clarify whether celastrol can induce apoptosis in a human leukemia HL-60 model system. Celastrol was found to induce apoptosis, and the rank order of the potency of celastrol and its derivatives to induce internucleosomal DNA fragmentation was found to be celastrol>cela-H>>the other derivatives=vehicle control. Many anticancer agents are known to possess the ability to inhibit topoisomerase II, so the inhibitory activities of celastrol and its derivatives on topoisomerase II were also explored. The rank order of the inhibitory activity was found to be celastrol>etoposide>cela-H, indicating that the apoptosis-inducing activities of cela derivatives correspond to their inhibitory activities on topoisomerase II. These data suggested that celastrol may cause its effects such as anticancer activity by the mechanism of apoptosis along with topoisomerase II inhibition.
TL;DR: The extraction of yacon leaves and chromatographic separation yielded two new antibacterial melampolide-type sesquiterpene lactones, which exhibited potent antimicrobial activity against Bacillus subtilis and Pyricularia oryzae, while 8β-tigloyloxymelampolid-14-oic acid methyl ester showed lower activity.
Abstract: The extraction of yacon [Smallanthus sonchifolius (Poepp. and Endl.) H. Robinson; Asteraceae] leaves and chromatographic separation yielded two new antibacterial melampolide-type sesquiterpene lactones, 8β-tigloyloxymelampolid-14-oic acid methyl ester and 8β-methacryloyloxymelampolid-14-oic acid methyl ester, as well as the four known melampolides, sonchifolin, uvedalin, enhydrin and fluctuanin. The newly identified compound, 8β-methacryloyloxymelampolid-14-oic acid methyl ester, exhibited potent antimicrobial activity against Bacillus subtilis and Pyricularia oryzae, while 8β-tigloyloxymelampolid-14-oic acid methyl ester showed lower activity. Fluctuanin exhibited the strongest antibacterial activity against B. subtilis among these six sesquiterpene lactones.
TL;DR: A biosurfactant-producing strain, Bacillus licheniformis F2.2, was isolated from a fermented food in Thailand and was capable of producing a new biosURfactant, BL1193, as well as two kinds of popular lipopeptide biosurfacts, plipastatin and surfactin.
Abstract: A biosurfactant-producing strain, Bacillus licheniformis F2.2, was isolated from a fermented food in Thailand. The strain was capable of producing a new biosurfactant, BL1193, as well as two kinds of popular lipopeptide biosurfactants, plipastatin and surfactin. Mass spectrometry and FT-IR analysis indicated that BL1193 had a molecular mass of 1,193 Da with no peptide portion in the molecule. While plipastatin and surfactin were abundantly produced in a nutrient YPD medium, BL1193 was produced only in a synthetic DF medium containing no amino acids. According to an oil displacement activity test, the specific activity of BL1193 (6.53 kBS units/mg) is equivalent to that of surfactin (5.78-6.83 kBS units/mg).
TL;DR: Various substrates for MCTs, such as benzoic acid and acetic acid, strongly inhibited the permeation of ferulic Acid, demonstrating that ferulic acid is obviously transported by MCT.
Abstract: Our previous study (Biosci. Biotechnol. Biochem., 66, 2449-2457 (2002)), suggested that ferulic acid was transported via a monocarboxylic acid transporter (MCT). Transepithelial transport of ferulic acid was examined in this study by directly measuring the rate of its transport across Caco-2 cell monolayers. Ferulic acid transport was dependent on pH, and in a vectorical way in the apical-basolateral direction. The permeation of ferulic acid was concentration-dependent and saturable; the Michaelis constant was 16.2 mM and the maximum velocity was 220.4 nmol min-1 (mg protein)-1. Various substrates for MCTs, such as benzoic acid and acetic acid, strongly inhibited the permeation of ferulic acid, demonstrating that ferulic acid is obviously transported by MCT. Antioxidative phenolic acid compounds from dietary sources like ferulic acid would be recognized and transported by MCT by intestinal absorption.
TL;DR: The hypolipidemic effect of an exo-biopolymer produced from a submerged mycelial culture of Hericium erinaceus was investigated in dietary-induced hyperlipidemic rats.
Abstract: The hypolipidemic effect of an exo-biopolymer produced from a submerged mycelial culture of Hericium erinaceus was investigated in dietary-induced hyperlipidemic rats Hypolipidemic effects were proportionally increased with the increasing concentration of the exo-biopolymer for oral administration The exo-biopolymer, at the dose of 200 mg/kg body weight, substantially reduced the plasma total cholesterol (329%), LDL cholesterol (454%), triglyceride (343%), phospholipid (189%), atherogenic index (587%), and hepatic HMG-CoA reductase activity (202%) It increased the plasma HDL cholesterol level (311%) as compared to the control group The molecular mass of this exo-biopolymer measured by HPLC was under 40 kDa Total sugar and protein contents were 912 and 88%, respectively The sugar and amino acid compositions of the exo-biopolymer were analyzed in detail
TL;DR: The results suggest that oleamide should be a useful chemo-preventive agent against Alzheimer's disease.
Abstract: We screened 50 Korean traditional natural plants to measure the activation effect on choline acetyltransferase and attenuation of scopolamine-induced amnesia. The methanolic extracts from Zizyphus jujuba among the tested 50 plants, showed the highest activatory effect (34.1%) on choline acetyltransferase in vitro. By sequential fractionation of Zizyphus jujuba, the active component was finally identified as cis-9-octadecenoamide (oleamide). After isolation, oleamide showed a 65% activation effect. Administration of oleamide (0.32%) to mice significantly reversed the scopolamine-induced memory and/or cognitive impairment in the passive avoidance test and Y-maze test. Injection of scopolamine to mice impaired performance on the passive avoidance test (31% decrease in step-through latency), and on the Y-maze test (16% decrease in alternation behavior). In contrast, mice treated with oleamide before scopolamine injection were protected from these changes (12–25% decrease in step-through latency; 1–10% decreas...
TL;DR: The results suggested that enzymatically depolymerized guluronate and mannuronate oligomers induced the production of cytotoxic cytokines in human mononuclear cells, although the uronate polymers before depolymization had no such activity.
Abstract: Enzymatically depolymerized guluronate and mannuronate oligomers were prepared from polyuronates with an alginate lyase from a Pseudoalteromonas sp., and their effects on mononuclear cells from human peripheral blood were examined. Conditioned medium prepared by the incubation of cells with an untreated polyuronate had little effect on growth of human leukemic U937 cells, but a medium prepared with depolymerized uronate oligomers inhibited their growth. Inhibition was greater in a medium prepared with guluronate oligomer than one prepared with mannuronate oligomer. The cytotoxic activity of the medium was heat-labile and nondialyzable. Apoptotic nuclear morphological changes and increased caspase-3-like activity were found in U937 cells treated with a medium prepared with depolymerized uronates. The medium prepared with purified tetra-guluronate and tetra-mannuronate also was cytotoxic; these effects were inhibited by antibodies to tumor necrosis factor-alpha. Our results suggested that enzymatically depolymerized guluronate and mannuronate oligomers induced the production of cytotoxic cytokines in human mononuclear cells, although the uronate polymers before depolymerization had no such activity.
TL;DR: The dependence of activity on degree of polymerization of the uronates was tested and the pentamer was most active, but the mechanism of the action of unsaturated uronate on the cells remains to be solved.
Abstract: The root elongation activity of unsaturated oligomeric uronates from alginate on carrot and rice plants was investigated. Unsaturated oligomeric uronates were prepared by digesting polymannuronate (PM) and polyguluronate (PG) with an alginate lyase purified from Pseudoalteromonas sp. strain No. 272. The root elongation activity was measured by elongation in length of carrot- and rice-excised root incubated in the B5-medium containing 0.8% agar in the dark. PM and PG showed no activity, but the enzymatic digestion mixtures of PG had promoting activity on roots of both plants at a final concentration of 0.5 mg/ml. The maximum activity was obtained at 0.75 mg/ml. The dependence of activity on degree of polymerization of the uronates was tested and the pentamer was most active, but the mechanism of the action of unsaturated uronates on the cells remains to be solved.
TL;DR: 1,4,6-tri-O-galloyl-β-D-glucose (hydrolyzable tannin) showed the highest anti-oxidative activity against lipid peroxidation, even stronger than that of 3-tert.-butyl-4-hydroxyanisole (BHA).
Abstract: Forty-three polyphenols from tea leaves were evaluated for their anti-oxidative effect against lipid peroxidation by the ferric thiocyanate method in vitro. Among these, 1,4,6-tri-O-galloyl-β-D-glucose (hydrolyzable tannin) showed the highest anti-oxidative activity against lipid peroxidation, even stronger than that of 3-tert.-butyl-4-hydroxyanisole (BHA). The assay demonstrates that tea polyphenols, except for desgalloylated dimeric proanthocyanidins that possess a catechin structure in the upper unit and desgalloylated flavan-3-ols, and excepting theaflavin 3,3′-di-O-gallate, had more anti-oxidative activity than that of α-tocopherol. The chemical structure-activity relationship shows that the anti-oxidative action advanced with the condensation of two molecules of flavan-3-ols as well as with 3-O-acylation in the flavan skeleton such as that by galloyl, (3′-O-methyl)-galloyl, and p-coumaroyl groups.
TL;DR: In this article, potato chips made from tubers stored at 2 or 20°C for two weeks after harvest were analyzed by GC-MS and the acrylamide level in the former chips was higher than ten times of that in the latter, which was correlated with both glucose and fructose levels in the tubers.
Abstract: Acrylamide in potato chips made from tubers stored at 2 or 20°C for two weeks after harvest was analyzed by GC-MS. The acrylamide level in the former chips was higher than ten times of that in the latter, which was highly correlated with both glucose and fructose levels in the tubers.
TL;DR: The chiC gene was introduced into rice plants under the control of the increased CaMV 35S promoter and a signal sequence from the rice chitinase gene and produced in rice plants accumulated intercellularly and had the hydrolyzing activity against glycol Chitin.
Abstract: Chitinase C (ChiC) is the first bacterial family 19 chitinase discovered in Streptomyces griseus HUT6037. In vitro, ChiC clearly inhibited hyphal extension of Trichoderma reesei but a rice family 19 chitinase did not. In order to investigate the effects of ChiC as an increaser of plant resistance to fungal diseases, the chiC gene was introduced into rice plants under the control of the increased CaMV 35S promoter and a signal sequence from the rice chitinase gene. Transgenic plants were morphologically normal. Resistance to leaf blast disease caused by Magnaporthe grisea was evaluated in R1 and R2 generations using a spray method. Ninety percent of transgenic rice plants expressing ChiC had higher resistance than non-transgenic plants. Disease resistance of sibling plants within the same line was correlated with the ChiC expression levels. ChiC produced in rice plants accumulated intercellularly and had the hydrolyzing activity against glycol chitin.
TL;DR: Results indicated that this kind of plant chitinase might be safe and biodegradable biocontrol agent for use instead of conventional fungicides.
Abstract: We investigated whether a plant chitinase can be used as a biocontrol agent instead of chemical fungicides by spraying chitinase E (family 19; class IV) from a yam (Dioscorea opposita Thunb) alone or together with β-1,3-glucanase directly onto the surface of a powdery mildew infecting strawberry berries and leaves. Results were observed by eye and with a scanning electron microscope. The powdery mildew infecting the strawberries was degraded, mainly by the chitinase, and the disease did not appear again for more than 2 weeks. These results indicated that this kind of plant chitinase might be safe and biodegradable biocontrol agent for use instead of conventional fungicides.
TL;DR: In this paper, Adenylate cyclase deficient (cya) mutants of E. coli K-12 were found to be resistant to fosmidomycin, a specific inhibitor of the non-mevalonate pathway.
Abstract: Adenylate cyclase deficient (cya) mutants of E. coli K-12 were found to be resistant to fosmidomycin, a specific inhibitor of the non-mevalonate pathway, just like to fosfomycin. E. coli glpT mutants were resistant to fosfomycin and also to fosmidomycin. This fact shows that fosmidomycin was transported inside via the glycerol-3-phosphate transporter, GlpT. DNA micro-array analysis showed that the transcription of glpT and other genes concerning glycerol utilization were highly dependent on the presence of cAMP.
TL;DR: The structural and antimicrobial characteristics of Fa-AMPs indicated that they are a novel type of antimicrobial peptides belonging to a plant defensin family.
Abstract: Novel antimicrobial peptides (AMP), designated Fa-AMP1 and Fa-AMP2, were purified from the seeds of buckwheat (Fagopyrum esculentum Moench.) by gel filtration on Sephadex G75, ion-exchange HPLC on SP COSMOGEL, and reverse-phase HPLC. They were basic peptides having isoelectric points of over 10. Fa-AMP1 and Fa-AMP2 had molecular masses of 3,879 Da and 3,906 Da on MALDI-TOF MS analysis, and their extinction coefficients in 1% aqueous solutions at 280 nm were 42.8 and 38.9, respectively. Half of all amino acid residues of Fa-AMP1 and Fa-AMP2 were cysteine and glycine, and they had continuous sequences of cysteine and glycine. The concentrations of peptides required for 50% inhibition (IC50) of the growth of plant pathogenic fungi, and Gram-positive and -negative bacteria were 11 to 36 μg/ml. The structural and antimicrobial characteristics of Fa-AMPs indicated that they are a novel type of antimicrobial peptides belonging to a plant defensin family.