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Tamio Maitani

Publications and source records attributed to Tamio Maitani.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Analysis of chloramphenicol in honey and royal jelly by LC/MS/MS].

A sensitive and selective method using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was developed for the determination of chloramphenicol (CAP) in honey and royal jelly. Mass spectral acquisition was performed in the negative mode by applying multiple reaction monitoring. In LC separation, Mightyl RP-18GP and 10 mmol/L ammonium acetate-acetonitrile were used as the column and mobile phase, respectively. CAP in honey samples was diluted with water, while CAP in royal jelly was extracted with 1% metaphosphoric acid-methanol (4 : 6). The solutions were cleaned up with an Oasis HLB cartridge. The quantification limits of CAP in honey and royal jelly were 0.3 ng/g and 1.5 ng/g, respectively. The recoveries of CAP from both honey and royal jelly at the quantification limits were over 92%. Twenty honey products and seven royal jelly products were analyzed by the developed method. CAP was detected in one honey product at 0.6 ng/g and in six royal jelly products at the level of 1.5-17.8 ng/g. These results show that the developed method has satisfactory sensitivity selectivity and is useful for the determination of CAP residues in honey and royal jelly.

Chloramphenicol↗
PubMed2005

Development of a multiplex polymerase chain reaction method for simultaneous detection of eight events of genetically modified maize.

In this study, we developed a novel multiplex polymerase chain reaction (PCR) method for simultaneous detection of up to eight events of genetically modified (GM) maize within a single reaction. The eight detection primer pairs designed to be construct specific for eight respective GM events (i.e., Bt11, Event176, GA21, MON810, MON863, NK603, T25, and TC1507) and a primer pair for an endogenous reference gene, ssIIb, were included in the nonaplex(9plex) PCR system, and its amplified products could be distinguished by agarose gel and capillary electrophoreses based on their different lengths. The optimal condition enabled us to reliably amplify two fragments corresponding to a construct specific sequence and a taxon specific ssIIb in each of the eight events of GM maize and all of nine fragments in a simulated GM mixture containing as little as 0.25% (w/w) each of eight events of GM maize. These results indicate that this multiplex PCR method could be an effective qualitative detection method for screening GM maize.

Base Sequence↗
PubMed2005

Quantitative detection system for maize sample containing combined-trait genetically modified maize.

Various countries have established regulations that stipulate the labeling of agricultural commodities, feed, and food products that contain or are made from genetically modified (GM) material or that contain adventitious GM material in amounts that exceed certain threshold levels. While regulations in some countries refer to GM material on a weight per weight (w/w) percentage, the currently applied detection methods do not directly measure the w/w percentage of the GM material. Depending on the particular method and the sample matrix it is applied to, the conversion of analytical results to a w/w percentage is challenging or not possible. The first rapid PCR system for GM maize detection on a single kernel basis has been developed. The equipment for the grinding of individual kernels and a silica membrane-based 96-well DNA extraction kit were both significantly revised and optimized for this particular purpose, respectively. We developed a multiplex real-time PCR method for the rapid quantification of GM DNA sequences in the obtained DNA solutions. In addition, a multiplex qualitative PCR detection method allows for the simultaneous detection of different GM maize traits in each kernel and thereby for identification of individual kernels that contain a combination of two or more GM traits. Especially for grain samples that potentially contain combined-trait GM maize kernels, the proposed methods can deliver informative results in a rapid, precise, and reliable manner.

DNA, Plant↗
PubMed2005

Polymeric grape-seed procyanidins, but not monomeric catechins and oligomeric procyanidins, impair degranulation and membrane ruffling in RBL-2H3 cells.

Grape-seed proanthocyanidins (GSPs) are catechin polymers that are predicted to form helices in their global minimum-energy conformation and to have a mean degree of polymerization of seven (mDP = 7). The highly polymerized GSP-H fraction (mDP = 10) was found to impair degranulation in RBL-2H3 cells after stimulation with an antigen (Ag) and treatment with the Ca-ATPase inhibitor thapsigargin (Tg). In addition, GSP-H affected actin cytoskeleton and inhibited membrane ruffling in these cells, resulting in the suppression of exocytosis. By contrast, monomeric epicatechin, the dimeric procyanidins PA-1, PA-2, and PB-2, and the oligomerized GSP-L (mDP = 3) had no effect on membrane ruffling and degranulation. These findings indicate that the molecular size and length of GSP-H are needed for the inhibition of membrane ruffling and degranulation in RBL-2H3 mast-cell lines.

Actin Depolymerizing Factors↗
PubMed2005

Dietary unripe apple polyphenol inhibits the development of food allergies in murine models.

The incidence of type I allergic disorders has been increasing worldwide, particularly, the hypersensitivity to food. We first showed that apple condensed tannin (ACT) intake would inhibit the development of the oral sensitization and that the inhibition could correlate with the rise in the population of TCR(gamma)delta-T cells in the intestinal intraepithelial lymphocytes (IEL) using W/W(V) mice and B10A mice which were ovalbumin (OVA)-orally sensitized. Serum OVA-specific immunoglobulin E and immunoglobulin G1 titers in the OVA-orally sensitized W/W(V) and B10A mice ad libitium fed ACT were extremely inhibited compared to those of the control. The ACT intakes of OVA-sensitized W/W(V) and B10A mice inhibited the immediate reduction of the body temperature or the rise in serum histamine induced by active systemic anaphylaxis. The proportions of the TCR(gamma)delta-T cells in the IEL of the OVA-orally sensitized W/W(V) and B10A mice ad libitium fed ACT were significantly greater than that in the controls. Furthermore, ACT feeding by itself could induce the rise in the percentage of the TCR(gamma)delta-T cells among the IEL of the W/W(V) and B10A mice. This suggests that the ACT intake may prevent the development of food allergies and this effect could be correlated with the rise in the percentage of TCR(gamma)delta-T cells among the IEL.

Allergens↗
PubMed2005

Development of taxon-specific sequences of common wheat for the detection of genetically modified wheat.

Qualitative and quantitative Polymerase Chain Reaction (PCR) systems aimed at the specific detection and quantification of common wheat DNA are described. Many countries have issued regulations to label foods that include genetically modified organisms (GMOs). PCR technology is widely recognized as a reliable and useful technique for the qualitative and quantitative detection of GMOs. Detection methods are needed to amplify a target GM gene, and the amplified results should be compared with those of the corresponding taxon-specific reference gene to obtain reliable results. This paper describes the development of a specific DNA sequence in the waxy-D1 gene for common wheat (Triticum aestivum L.) and the design of a specific primer pair and TaqMan probe on the waxy-D1 gene for PCR analysis. The primers amplified a product (Wx012) of 102 bp. It is indicated that the Wx012 DNA sequence is specific to common wheat, showing homogeneity in qualitative PCR results and very similar quantification accuracy along 19 distantly related common wheat varieties. In Southern blot and real-time PCR analyses, this sequence showed either a single or a low number of copy genes. In addition, by qualitative and quantitative PCR using wx012 primers and a wx012-T probe, the limits of detection of the common wheat genome were found to be about 15 copies, and the reproducibility was reliable. In consequence, the PCR system using wx012 primers and wx012-T probe is considered to be suitable for use as a common wheat-specific taxon-specific reference gene in DNA analyses, including GMO tests.

Base Sequence↗
PubMed2005

Comparative studies of the quantification of genetically modified organisms in foods processed from maize and soy using trial producing.

Seven types of processed foods, namely, cornstarch, cornmeal, corn puffs, corn chips, tofu, soy milk, and boiled beans, were trial produced from 1 and 5% (w/w) genetically modified (GM) mixed raw materials. In this report, insect resistant maize (MON810) and herbicide tolerant soy (Roundup Ready soy, 40-3-2) were used as representatives of GM maize and soy, respectively. Deoxyribonucleic acid (DNA) was extracted from the raw materials and the trial-produced processed food using two types of methods, i.e., the silica membrane method and the anion exchange method. The GM% values of these samples were quantified, and the significant differences between the raw materials and the trial-produced processed foods were statistically confirmed. There were some significant differences in the comparisons of all processed foods. However, our quantitative methods could be applied as a screening assay to tofu and soy milk because the differences in GM% between the trial-produced processed foods and their raw materials were lower than 13 and 23%, respectively. In addition, when quantitating with two primer pairs (SSIIb 3, 114 bp; SSIIb 4, 83 bp for maize and Le1n02, 118 bp; Le1n03, 89 bp for soy), which were targeted within the same taxon specific DNA sequence with different amplicon sizes, the ratios of the copy numbers of the two primer pairs (SSIIb 3/4 and Le1n02/03) decreased with time in a heat-treated processing model using an autoclave. In this report, we suggest that the degradation level of DNA in processed foods could be estimated from these ratios, and the probability of GM quantification could be experimentally predicted from the results of the trial producing.

Animals↗
PubMed2005

Applicability of the quantification of genetically modified organisms to foods processed from maize and soy.

The applicability of quantifying genetically modified (GM) maize and soy to processed foods was investigated using heat treatment processing models. The detection methods were based on real-time quantitative polymerase chain reaction (PCR) analysis. Ground seeds of insect resistant GM maize (MON810) and glyphosate tolerant Roundup Ready (RR) soy were dissolved in water and were heat treated by autoclaving for various time intervals. The calculated copy numbers of the recombinant and taxon specific deoxyribonucleic acid (DNA) sequences in the extracted DNA solution were found to decrease with time. This decrease was influenced by the PCR-amplified size. The conversion factor (Cf), which is the ratio of the recombinant DNA sequence to the taxon specific DNA sequence and is used as a constant number for calculating GM% at each event, tended to be stable when the sizes of PCR products of two DNA sequences were nearly equal. The results suggested that the size of the PCR product plays a key role in the quantification of GM organisms in processed foods. It is believed that the Cf of the endosperm (3n) is influenced by whether the GM originated from a paternal or maternal source. The embryos and endosperms were separated from the F1 generation seeds of five GM maize events, and their Cf values were measured. Both paternal and maternal GM events were identified. In these, the endosperm Cf was lower than that of the embryo, and the embryo Cf was lower than that of the endosperm. These results demonstrate the difficulties encountered in the determination of GM% in maize grains (F2 generation) and in processed foods from maize and soy.

Animals↗
PubMed2005

Binding affinity of aluminium to human serum transferrin and effects of carbohydrate chain modification as studied by HPLC/high-resolution ICP-MS--speciation of aluminium in human serum.

Aluminium (Al) in the blood is bound to transferrin (Tf), a glycoprotein of about 80kDa that is characterized by its need for a synergistic anion. In this focused review, the binding affinity of Al to Tf is surveyed in the context of our recent studies using on-line high-performance liquid chromatography/high-resolution inductively coupled plasma mass spectrometry (HPLC/HR-ICP-MS). Al in human serum without any in vitro Al-spikes was present in a form bound to the N-lobe site of Tf. The influences of sialic acid in the carbohydrate chain of human serum Tf (hTf) were studied using asialo-hTf, obtained by treatment with sialidase. The binding affinity of Fe was similar between asialo-hTf and native-hTf, while that of Al for asialo-hTf was larger than that for native-hTf, especially in the presence of oxalate, a synergistic anion. The above findings are discussed in relation to diseases in which the serum concentrations of carbohydrate-deficient Tf and oxalate are augmented.

Aluminum↗
PubMed2005

The hyperresponsiveness of W/W(v) mice to oral sensitization is associated with a decrease in TCRgammadelta-T cells.

We have already reported that WBB6F1-W/W(v) (W/W(v)) mice, which have mutations in the c-kit gene, are highly susceptible to oral sensitization, and that the proportion of TCRgammadelta-T cells among the intraepithelial lymphocytes (IELs) (gammadelta-IELs) of W/W(v) is much lower than in congenic wild-type (+/+) mice. In this study we examined an inhibitory role of gammadelta-IELs in oral sensitization using two different methods. First, wild-type (+/+) mice were sensitized by oral administration of 1.0 mg ovalbumin (OVA) by gavage every day for 9 weeks after anti-TCRgammadelta antibody treatment 4 times. The treatment resulted in an enhanced OVA-specific IgG1 antibody production, active systemic anaphylaxis (ASA), and Th2-dominant cytokine production. Next, W/W(v) mice whose bone marrow cells were reconstituted from C57BL/6J mice for 5 months were sensitized by oral administration of OVA. The OVA-specific IgG1 antibody titer in the bone marrow-reconstituted W/W(v) mice was neither significantly enhanced, nor ASA was induced. The proportion of gammadelta-IELs in the reconstituted mice was much higher than that in the untreated W/W(v) mice. The above findings suggest that the decrease or increase in number of gammadelta-IELs enhances or decreases oral sensitization respectively. These results show that gammadelta-IELs have an important role in the oral tolerance to food antigens.

Administration, Oral↗
PubMed2005

Contamination levels of PCDDs, PCDFs and Co-PCBs in commercial baby foods in Japan.

To examine dioxin contamination in commercial baby foods in Japan, congener analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) were performed on 102 varieties of baby foods obtained from supermarkets in 2001-2002. The toxic equivalent quantity (TEQ) levels for dioxins in samples ranged from < 0.001 to 0.135 pg-TEQ/g wet weight when undetected or trace levels of congeners were taken as zero. Among 102 samples tested, 26 samples exceeded 0.010 pg-TEQ/g. The highest TEQ value was for "sardine, vegetables" (0.135 pg-TEQ/g), followed by "Japanese radish (daikon), sardine" (0.080 pg-TEQ/g). Thus, dioxins were detected at low levels in baby foods containing animal products such as fishes and/or dairy products.

Benzofurans↗
PubMed2005

[Laboratory-performance study of the notified methods to detect genetically modified papaya (55-1)].

To investigate important factors affecting the reliability of the analytical results, proficiency tests were attempted for the histochemical method (GUS method) and the qualitative PCR method (PCR method) to detect genetically modified papaya (55-1) in the Japanease official method. The test samples were distributed to twenty-three laboratories that participated in the study and were examined according to the protocol. All the data collected from participating laboratories were statistically analyzed. In the PCR method, one negative sample was detected as positive using detection primers in one laboratory, though the sample was negative when checked using confirmation primers. Contamination might have occurred in the step of the preparation of the PCR sample solution using detection primers. In the GUS method, all the test samples were identified as expected. Thus, all the laboratories reported correct results overall.

Carica↗
PubMed2005

[Laboratory performance study of the quantitative detection method for genetically modified soybeans (roundup ready soybeans 40-3-2)].

To investigate important factors affecting the analytical results, a laboratory-performance study was attempted for the Japanese official methods to detect genetically modified (GM) soybeans (40-3-2). Test samples containing 0, 1 and 5% GM soya powder in non-GM soya powder was prepared. A set of 3 test samples was sent to the participating laboratories along with the protocol. The data were collected from all laboratories and statistically analyzed. In the real-time PCR detection method, the average values of the GM 1% and 5% samples were both much lower than the spiked value because the laboratories using a silica-membrane DNA extraction method underestimated the GM value. On the other hand, the laboratories using other extraction methods, such as the CTAB method obtained values close to the spiked value. These results suggest that use of the silica-membrane DNA extraction method may result in underestimation of the GM content in the real-time PCR method. In the ELISA method, the average value of 5% spiked samples appears to be slightly higher than the fortified value. But, overall, it was considered that reported values were close to the spiked level.

DNA, Plant↗
PubMed2005

[Determination of isophorone in foods].

Isophorone (ISP) is used widely as a solvent of natural and synthetic resins, wax, printing ink, pesticides and paints. In this study, the level of ISP in various foods (93 samples) was analyzed. ISP was collected from samples by steam distillation after the addition of an internal standard, deuterium-labeled ISP, then extracted with dichloromethane, cleaned up on a silica gel column, and determined by GC/MS. ISP was barely detected in fish, meat and vegetable samples, but it was detected in rice, wheat, beans and their processed products, miso, soy sauce and fermented soybeans (natto). The maximum level was 8.9 ng/g in miso. The packaging materials of the foods contained little ISP, and so the source of ISP in the foods could not be clarified.

Cyclohexanones↗
PubMed2005

[Establishment of standards and specifications for chemical substances in foods and evaluation of exposure to maintain food safety].

Currently, consumers are very anxious about many chemical substances contained in foods. To maintain food safety, the Ministry of Health, Labour and Welfare of Japan establishes standards and specifications on toxic chemical substances in foods, establishes analytical methods for surveillance, and investigates the daily dietary intake of food contaminants every year. This paper describes what sorts of standards and specifications for toxic chemical substances in foods have been established and what kinds of research on daily dietary intake have been performed. As the subjects for description, pesticide residues, toxic metals, dioxins, acrylamide, food additives, genetically modified food products, so-called health foods, and food allergens are included.

Allergens↗