Publications by authors named "Nakama A"

Background: Over one third of all animal phyla utilize a mode of early embryogenesis called 'spiral cleavage' to divide the fertilized egg into embryonic cells with different cell fates. This mode is characterized by a series of invariant, stereotypic, asymmetric cell divisions (ACDs) that generates cells of different size and defined position within the early embryo. Astonishingly, very little is known about the underlying molecular machinery to orchestrate these ACDs in spiral-cleaving embryos.

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We surveyed prevalence and contamination levels of Listeria monocytogenes in ready-to-eat foods between 2000 and 2012 in Tokyo. L. monocytogenes was isolated from 52 (1.

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There is a strain of Clostridium perfringens, W5052, which does not produce a known enterotoxin. We herein report that the strain W5052 expressed a homologue of the iota-like toxin components sa and sb of C. spiroforme, named Clostridium perfringens iota-like enterotoxin, CPILE-a and CPILE-b, respectively, based on the results of a genome sequencing analysis and a systematic protein screening.

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PCR serogrouping methods were used to examine strains of L. monocytogenes isolated in Japan. Among 187 strains, 99.

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Article Synopsis
  • The review examines genetic conditions that provide advantages against specific infectious diseases, highlighting examples like malaria and hemoglobinopathies.
  • It discusses pairings of diseases and genetic disorders, noting that some are influenced by geographic selection pressures, while others may occur by chance.
  • The findings suggest potential avenues for treatment development in infectious diseases lacking effective cures, such as HIV and Ebola, by leveraging the known interactions between these genetic conditions and pathogens.
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Staphylococcal food poisoning (SFP), one of the commonest food-borne diseases, results from the ingestion of one or more staphylococcal enterotoxins (SEs) produced in foods by Staphylococcus aureus. In the present study, 203 S. aureus strains originating from 83 outbreaks that had occurred in Tokyo were examined for their coagulase type and genotype of SEs to analyze their molecular epidemiological characteristics.

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We describe a simple method for discrimination of Aspergillus flavus group fungi, including aflatoxin (AF) producers, by means of molecular-biological analysis of 45 strains of A. flavus. First, 20 strains of A.

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Group C rotavirus (GCRV), astrovirus (AstV), and adenovirus (subgenus F AdenoV) are etiologic agents of acute nonbacterial gastroenteritis, which often represents community outbreaks. For the efficient detection of GCRV, AstV, and subgenus F AdenoV in stool specimens, a multiplex real-time PCR assay was developed to detect these three viruses simultaneously, with high sensitivity and specificity. In total, 8404 clinical specimens were collected between April 2008 and March 2011 and tested for GCRV, AstV, and subgenus F AdenoV by the multiplex real-time PCR, as well as for norovirus (NoV), sapovirus (SaV), and group A rotavirus (GARV) by non-multiplex real-time PCR.

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Coxiella burnetii is the causative agent of Q fever, and the main route of infection in humans is inhalation of contaminated aerosols. Although oral transmission by contaminated raw milk or dairy products is also a possible route of human infection, there have been few studies investigating the presence of C. burnetii in dairy products.

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The antimicrobial susceptibility of 201 Listeria monocytogenes isolates from foods, environments, animals and human patients in Japan was determined. All isolates were susceptible to ampicillin, the first choice of drug for listeriosis treatment, chloramphenicol, dihydrostreptomycin, erythromycin, enrofloxacin, gentamicin, kanamycin, lincomycin, nosiheptide, salinomycin, vancomycin, and virginiamycin. A human strain was resistant to oxytetracycline.

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Enterotoxigenic Escherichia coli (ETEC) caused 131 outbreaks in Tokyo, Japan, between 1966 and 2009. The major serogroups were O6, O27, O148, and O159. The incidence of serogroups O25 and O169 recently increased.

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Norovirus (NV) RNA has rarely been detected in foods despite the use of highly sensitive methods such as RT-PCR and real-time RT-PCR. In the modified method (A3T method) reported previously, a bacterial culture process was introduced into the standard protocol for NV detection to remove some inhibitor(s) present in food ingredients. To confirm the efficiency of the A3T method and to examine NV contamination in bivalve molluscs, we tried to detect NV RNA in bivalve molluscs on the market and in oyster samples associated with foodborne outbreaks by using the standard method and the A3T method.

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The simplified international diagnostic criteria for autoimmune hepatitis (AIH), re-revised by the International AIH Group in 2008, were investigated in 114 patients with AIH from 15 centers in Japan. While applying of the criteria, we had to pay attention to anti-nuclear antibody measurement methods, and liver histology scoring. Definite and probable AIH were diagnosed in 83 and 22 patients, respectively.

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Background: Double-balloon endoscopy (DBE) examinations are not yet widely accepted as routine procedures for examining the small bowel of patients with Crohn's disease (CD).

Aim: To evaluate the feasibility and usefulness of DBE for CD in tertiary-care hospitals.

Methods: Between July 2004 and September 2008, 1444 DBE procedures were performed for 704 patients in 6 tertiary-care hospitals.

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Cruciferous vegetables and their isothiocyanates are promising foods and agents for cancer prevention. We focus here on the effects of mustard oil (SMO) in a variety of the Japanese radish, Shibori Daikon (Raphanus sativus), on the proliferation of 3Y1 rat fibroblasts and the H-ras-transformed derivative, HR-3Y1-2. SMO (1.

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Single-laboratory method performance parameters were evaluated for analysis of biotin in total diet samples by hydrolyzed extraction and microbiological assay with Lactobacillus plantarum. The method was shown to be accurate, repeatable, rugged, and applicable for the determination of biotin in a broad range of matrixes and concentrations of total diet samples. The measurement uncertainty was evaluated with all food sample groups by combining the relative uncertainty of precision, recovery from each food group, and interday variation factors calculated from the ruggedness test results.

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The in vitro cellular functions of differentiated cells are influenced by culture conditions. Effects of several extracellular matrices (ECMs) on cytochrome P450-dependent monooxygenases (MFOs) induction and cytochrome P4501A1 (CYP1A1) gene expression were estimated in Hep G2 cells cultured in a serum-free medium. The cells were cultured on collagen type I- and II-, fibronectin-, and matrigel-coated dishes and MFO activities were induced by the addition of 3-methylcholanthrene (MC).

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Biocides have been used not only in everyday items such as clothes, kitchenware, daily necessities, and infant utensils, but also in cosmetics and wrapping papers for foodstuffs. Since there is a high possibility of exposure to biocides from such materials, their safety must be assessed adequately using a range of methods. We investigated the estrogenic activity of 20 organic biocides using two in vitro screen assays: estrogen receptor (ER) binding assay and yeast estrogen screen (YES) assay.

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A PCR method for the effective detection of Coxiella burnetii in commercially available mayonnaise was developed. Sample preparations were isolated from 50 g portions of each mayonnaise product by four successive extraction steps in phosphate buffer with 2.0 M NaCl.

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A method is described for determination of selenium in sediment by isotope-dilution inductively coupled plasma mass spectrometry with an octapole reaction cell (ID-ICP-ORCMS). Sediment samples were digested with HNO3, HClO4, and HF, and the digestion included an elaborate evaporation process to remove bromine from the digested solution. Simple strong cation-exchange disk filtration was used to remove rare earth elements (REE) from the digested solution, because REE2+ seriously interfere with Se isotopes (i.

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A total of 244 milk samples collected from supermarkets in Tokyo were examined for contamination with Coxiella burnetii. C. burnetii DNA was detected in 131 (53.

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A rapid and simple DNA extraction method is needed to detect genetically modified recombinant DNA in soybean kernels and processed foods. However, since various kernels and processed foods differ greatly in form, a uniform DNA extraction method has proved elusive. The silica-base resin DNA extraction method does not use any organic solvent, and the operation is simple and the cost per extraction is low, although the frequency of its use is very low and few domestic reports exist.

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In the present study, we developed a rapid umu-microplate test system that uses the nitroreductase- and O-acetyltransferase-overproducing Salmonella typhimurium strain NM3009 and the O-acetyltransferase-overproducing S. typhimurium strain NM2009 to detect genotoxic activity in small volume samples. The assay was used to test the genotoxicity of several standard mutagens and environmental samples.

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Two types of sediment reference material (NMIJ 7302-a and 7303-a) for trace elements analysis have been prepared and certified by the National Metrology Institute of Japan in the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). The original materials were collected from a bay near industrial activity in Kyushu (NMIJ CRM 7302-a; marine sediment) and from Lake Biwa (NMIJ CRM 7303-a; lake sediment). The sediment materials were air-dried, sieved, homogenized, packaged in 1000 glass bottles (60 g each), and radiation sterilized.

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A previously developed and highly sensitive umu-microplate test system based on the nitroreductase- and O-acetyltransferase-overproducing strain Salmonella typhimurium NM3009 and the O-acetyltransferase-overproducing strain S. typhimurium NM2009 was applied to the detection of genotoxic activity in atmospheric particles in urban areas using a relatively small sample load. The results showed that the test system was able to detect slight increases in induced genotoxicity in atmospheric particles and that genotoxicity was detected mainly in the fine fraction but also partially in the coarse fraction.

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