Research interests in studying the biochemical nature of selenium have increased and the importance of this element as an essential micronutrient in many organisms has been well recognized. Selenium occurs in proteins in the form of the 21st amino acid, selenocysteine (SeCys or Sec). In this review, we describe the speciation analysis of the fish-specific selenoproteins and non-proteinous selenium compounds, and the nutritional bioavailability of selenium from seafood materials. Selenium is essential to fish and shellfish. The selenoproteomes (sets of SeCys-containing proteins) of fish are greater in number than those of mammals (25 selenoproteins in humans); at 30-37 selenoproteins, the selenoproteomes of fish are among the largest known. The same core selenoprotein families are found in mammals and fish. In addition, fish have several species-specific selenoproteins [fish 15 kDa selenoprotein-like protein (Fep 15), selenoprotein J and selenoprotein L] that are missing in mammals. Actually, not only proteinous selenium species like selenomethionine (SeMet) and SeCys derivatives, but also many non-proteinous organic ones were detected in fish and shellfish samples. Although the selenium contents in seafood are higher than in terrestrial foodstuffs, little is known about the chemical forms of organoselenium species in seafood. The nutritional bioavailability of selenium from seafood appears to be dependent on the fish and shellfish species and/or place where they are produced; some seafood gives rise to a high bioavailability of selenium, which is comparable to that of wheat and beef. Fish and shellfish materials are major dietary sources of selenium for the Japanese population (∼60% of daily intake). Seafood materials appear to contain nutritionally effective organoselenium compounds that have not yet been chemically identified.

抄録全体を表示

This study was made to investigate the anti-diabetic and antioxidant potential of ethanolic extract of seeds of Psoralea corylifolia L. in streptozotocin (STZ) nicotinamide induced type-2 diabetic rats. Male Albino Wistar rats (150-250 g) were taken for the study. The ethanolic extract of seeds of Psoralea corylifolia was prepared and the oral administration of this extract tested for anti-hyperglycemic activity in streptozotocin-nicotinamide induced diabetic rats showed significant effect on blood glucose level in acute and chronic study. The body weight, oral glucose tolerance test and biochemical parameter such as insulin level, liver glycogen contents, glycosylated hemoglobin, total plasma cholesterol and antioxidant parameters were estimated for all treated group and compared against diabetic control group. In oral glucose tolerance test both dose (200 and 400 mg/kg) intensively reduced external glucose level. After 28 days (chronic study) of treatment with extract the maximum reduction in blood glucose level were observed in streptozotocin-nicotinamide rats with ethanolic extract 400 mg/kg body weight per os. There were significant increase in body weight, liver glycogen content, plasma insulin level and decrease in the blood glucose, glycosylated hemoglobin level and total plasma cholesterol. However it also influences on the antioxidant parameters like decreases malondialdehyde (MDA) level and increases reduced glutathione (GSH) level. This investigation results that Psoralea corylifolia has significant antihyperglycemic and antioxidant activity.

抄録全体を表示

Recently, many contact dermatitis cases related to leather furniture and footwear containing dimethyl fumarate (DMF) as an anti-mold agent have been reported in European countries. We investigated the concentrations of DMF and several fumaric and maleic acid diesters in desiccants and household products (footwear and rack) enclosed with a desiccant sachet in Japan. We sorted the product samples by material, and analyzed the product parts that can come into contact with the skin of consumers. Twenty-one desiccant samples and eighteen product samples (seven footwear products and one rack product) were analyzed. DMF was detected in the range of 0.11-2.3 mg/kg in two desiccant samples and three product samples (different parts of one product). The DMF concentrations detected in this study exceeded the value regulated by the European Union (0.1 mg/kg); the concentration of one desiccant sample was exceeded 1.0 mg/kg which showed a strong reaction in the patch tests in a precious study. The notes printed on the sachets of the desiccant samples containing DMF read “mold-proof desiccant” and “do not eat” in one case and merely “do not eat” in the other case. DMF has strong sensitization and irritation activities; hence, it is necessary to analyze more samples to prevent DMF-related contact dermatitis in Japan. Dibutyl maleate (DBM) was detected in the rack product and enclosed desiccant; its concentration ranged from 29 to 720 mg/kg. DBM may be a constituent of the adhesive used for the rack. Further investigation is necessary to verify the cross-reaction of DBM with DMF.

抄録全体を表示

Lead (Pb) is a toxic heavy metal widely distributed in the environment. Recent studies suggest oxidative stress as one possible mechanism involved in Pb poisoning. The unicellular algae Chlorella vulgaris (CV) contains various bioactive substances with antioxidant for the prevention of oxidative stress by metals. We investigated the protective effects of CV on the oxidative system in five groups of male Sprague-Dawley rats fed American Institute of Nutrition (AIN)-76 diet, plus 2, 5 or 10% CV for 4 weeks. All animals were exposed to 200 mg/l lead acetate by drinking water except for the control (tap water). Body weight gains were significantly reduced in the Pb-exposed group (64%) relative to the control and CV groups. Brain weights were significantly increased in the Pb-exposed group (44%) relative to the others. In the experimental period, food intake, water intake and Pb intake were not different among the groups. The levels of Pb (87%) in brain obtained from the Pb-exposed group were significantly increased compared to the other groups. The levels of oxidative stress parameters in the brain such as superoxide dismutase (36%), glutathione peroxidase (63%), and glutathione reductase (30%) were decreased in the Pb-exposed group relative to the control but markedly increased in the CV groups. The CV also significantly increased glutathione levels by approximately 1.7-fold over the Pb-exposed group, while the malondialdehye concentration significantly decreased by approximately 47-71%. Based on these results, we found alterations in several indicators of oxidative stress of Pb intoxication, suggesting the antioxidant potential of CV. Therefore, CV may have protective effects on brain damage of low-level and short-term Pb exposure in the brains of rats.

抄録全体を表示

Guangdong Herbal Tea (GHT) has been consumed as a traditional remedy for Shanghuo in southern China for a long time. Shanghuo, a traditional Chinese concept, is a physiological process of uncoordinated response to stress with physical and mental fatigue syndromes. In this study, we investigated the main components and anti-stress effects of GHT in restrain-stressed mice. The high-performance liquid chromatography (HPLC) fingerprint of GHT extract was recorded and the chemicals of main peaks were identified. The effects of GHT on number and activity of nature killer (NK) and T cells, cytokines and the antioxidative activity of splenocytes were studied in restrained mice. Results showed oral administration of GHT prevented stress-induced immunocompromise by improving splenocyte number, NK cell response against mouse T cell lymphoma cells (YAC)-1 cell and antitumor T cell response against syngeneic P815 in the spleens of mice loaded with acute restraint stress. GHT also significantly improved the proportion of T-helper (Th) type lymphocyte, the production of Th cell-dependent cytokines and the antioxidative activity of splenocytes. These results indicated that GHT attenuates stress by increasing the numbers and activities of immunocytes in restraint mice, by exerting antioxidative activity directly or indirectly in immunocytes.

抄録全体を表示

Genetic and epigenetic studies are required to understand molecular mechanisms of carcinogenesis and tumorigenesis. Although alterations of DNA methylation and histone modification profiles are observed in cancer cells, the knowledge of the epigenetic regulatory factors involved in carcinogenesis is insufficient. In this study, we showed that the histone variant, H2a.z, and the histone methyltransferase, Pr-set7/Set8/KMT5a, were up-regulated during chemically induced hepatocarcinogenesis. During this process, the glutathione S-transferase placental form (GST-P), which is completely repressed in normal liver, is strongly induced and is therefore an excellent tumor marker. Reporter analysis performed using the regulatory region of the Gst-p gene revealed that H2A.Z and PR-SET7 repressed Gst-p promoter activity. The enhancer element responsible for hepatocarcinogenic-specific gene expression was required for repression by H2A.Z, and the negative regulation by PR-SET7 mediated the regulatory element but not the enhancer. Furthermore, we examined the effects of overexpression of H2A.Z and PR-SET7 on the colony formation activity of mouse NIH-3T3 cells grown on a soft agarose medium. Colony formation based on anchoring independent cell growth is a feature of malignant transformed cells. These factors did not exhibit colony formation activity but repression of the ras oncogene induced this activity. PR-SET7 suppressed RAS^val12-mediated colony formation through methyltransferase activity. These results suggest that H2a.z and Pr-set7 that are induced during hepatocarcinogenesis may function as carcinogenesis suppressors.

抄録全体を表示

Estrogenic and antiestrogenic activities of 19 quinoid polycyclic aromatic hydrocarbons (PAHQs) and 9 ketone PAHs were evaluated by the yeast two-hybrid assay using yeast cells expressing estrogen receptor-α (ERα). Binding affinity of PAHQs to ERα was assayed by the polarized fluorescence method using Fluormone^TM ES2. Ten PAHQs having 3-5 rings showed antiestrogenic activities. The most strongly antiestrogenic PAHQs were 1,4-chrysenequinone and 5,6-chrysenequinone. On the other hand, benzo[a]pyrene-3,6-quinone showed the strongest estrogenic activity. However, the other compounds tested did not show so strong estrogenic/antiestrogenic activities. Binding affinity to ER was required but not sufficient for estrogenic/antiestrogenic activities of PAHQs. The length-to-breadth ratios of the rectangular planes surrounding the ring molecules and the distances between the oxygen atom of the carbonyl group and farthest hydrogen atom of estrogenic/antiestrogenic PAHQs were in narrow ranges, suggesting a structure-activity relationship. As interactions between active PAHQ and ER, hydrogen bonding between carbonyl groups and amino acid residues and van der Waals forces were considered.

抄録全体を表示

Five hundred and ninety seven Escherichia coli (E. coli) isolates were obtained from clinical specimens at the Songklanagarind Hospital in Songkhla Province, Thailand during 2003-2005. Antimicrobial susceptibilities to ten antimicrobial agents were tested by a standard disk diffusion method. The presence of class 1 integrons was based on the detection of the integrase gene (intI1) by PCR. Extended-spectrum β-lactamases (ESBLs) were detected by a combination disk method. The highest percentage of resistance was found to ciprofloxacin (40.5%), norfloxacin (39.0%), and cefuroxime (33.2%). The IntI1 was detected in 59.5% of the tested isolates. Resistance to gentamicin, cefazolin, cefuroxime, cefotaxime, ceftriaxone, norfloxacin, and ciprofloxacin was significantly higher in class 1 integron-positive isolates (p<0.05). The most prominent resistance pattern was for norfloxacin-ciprofloxacin (17.7%). ESBLs were detected in 75 out of 597 (12.6%) isolates; 56/302 (18.5%) and 19/295 (6.4%) were from hospitalized and non-hospitalized patients, respectively. Seventy-five percent of ESBL-positive strains were integron-positive isolates. Imipenem and meropenem were still able to inhibit all ESBL-producing strains. The results indicated that class 1 integrons are widely prevalent among clinical isolates of resistant E. coli especially in ESBL-producers and are probably a reservoir for producing multidrug resistance and nosocomial infections in hospitals.

抄録全体を表示

Cimicifuga heracleifolia (CH) ethanol extract and its constituents such as ferulic acid, caffeic acid, 24-epi-7,8-didehydrocimigenol-3-xyloside, and 23-O-acetylshengmanol 3-xyloside were investigated for their abilities to prevent gastric injury. To elucidate their gastric-protective effects, we assessed 1,1-diphenyl-2-picrylhydrazyl radical-radical scavenging activity and inhibition of Helicobacter pylori (H. pylori) and gastric cancer cells. Ferulic acid and caffeic acid exhibited higher free radical scavenging activity than other constituents and inhibited the colonization of H. pylori effectively. Furthermore, 24-epi-7,8-didehydrocimigenol-3-xyloside and 23-O-acetylshengmanol-3-xyloside showed cytotoxicity in gastric cancer cells (SNU638 and AGS cells). These results suggest the novel activities of CH ethanol extract and its constituents. CH ethanol extract and its constituents could be utilized for the treatment and/or prevention of gastric injury.

抄録全体を表示

Our previous study revealed that phthalate esters (PEs), a group of suspected endocrine-disrupting chemicals, acquire estrogenic activities by ring 4-hydroxylation. In addition, the estrogenic activities are modified depending on alkyl chain structures (chain length and branching), which can be altered in the environmental conditions such as microbial degradation. Therefore, it is important to determine the environmental fate of these alkyl chains to evaluate the biological impact of PEs on humans and wildlife. PEs are known to undergo biodegradation via sequential hydrolysis, resulting in the formation of monoester and dicarboxylic acid forms. In this study, dipropyl phthalate chosen as one of PEs was cultivated with Acinetobacter lwoffii, a known PE-degrading bacterium, in the presence of a limited amount of CH₃OH as a PE-solvent. As a result, several unknown biotransformation products were detected. The products were characterized as methyl propyl phthalate, dimethyl phthalate, and monomethyl phthalate, suggesting that environmental PEs are processed through novel biotransformation pathways. The products can be produced both by esterification of monoester forms and transesterification of diester forms. However, when monobutyl phthalate—a monoester of dibutyl phthalate—was used as a substrate, esterified products were not detected, indicating phthalate methyl esters were formed via transesterification. A stable-isotope tracer experiment using CD₃OH instead of CH₃OH revealed the production of phthalate methyl esters, the molecular ions of which shifted by 3 or 6 atomic mass units. These results revealed that PE was bacterially transformed via transesterification in the presence of alcohol. We demonstrated that PEs are transformed in the environment via more diverse ways than expected, although the environmental concentration of alcohols is very low. It would be worthwhile to perform a systematic assessment on the possibility that transesterification products may be associated with the potential adverse effects of PEs in the environment.

抄録全体を表示

2-Chloroethanol (2-CE) has been used on grapevines to accelerate grape growth, and its metabolite, chloroacetaldehyde (CAA), accumulated in the liver and blood from rats intoxicated with 2-CE. Chronic occupational injury might be a possible reason for the 2-CE intoxication. In this study, we used the in vitro and in vivo tests to examine the genotoxicity of 2-CE and CAA. First, 2-CE did not induce chromosome aberration formation in Chinese ovary hamster cells, but CAA did induce chromosome aberration formation, especially the chromosome gap-type aberration after S9 activation. Second, 2-CE at high doses (1/2 LD₅₀), but not at low doses, induced peripheral blood micronucleus formation in mice. CAA induced micronucleus formation at low and high dosages (1/8-1/2 LD₅₀). These results indicated that CAA plays an important role in 2-CE chronic intoxication, and the genotoxic mechanisms of CAA require further study.

抄録全体を表示

Lactobacillus pentosus S-PT84, which was isolated from Kyoto pickles, enhances splenic natural killer (NK) cell activity, increases IgA production from Peyer's patch cells and has high T-helper 1 (Th1) cytokine and type 1-interferon-inducing activity. However, all of these effects were obtained by using heat-killed S-PT84. In the present study, we investigated the immunomodulatory effect of live and heat-killed S-PT84 in BALB/c mice. Unexpectedly, live S-PT84 indicated weak activity on Th1 cytokine (interleukin-12 or interferon-γ) production from splenocytes compared to heat-killed S-PT84 in vitro. Similar tendencies were also shown in S-PT84 having different cell wall thickness. Next, we compared the immunomodulatory effect after oral ingestion of each S-PT84. The results indicated splenic NK activity was equally enhanced by live or heat-killed S-PT84 ingestion, though heat-killed S-PT84 indicated slightly higher activity in interferon-γ production and inclination toward Th1 immunity. These results suggested that both live and heat-killed S-PT84 have an equal immunomodulatory effect in BALB/c mice. It is thought that the use of heat-killed S-PT84 is advantageous from the viewpoint of ease of handling compared to live S-PT84.

抄録全体を表示