Acrylamide concentrations in processed foods (63 samples covering 31 product types) from Japan were analysed by LC-MS/MS and GC-MS methods. The limit of detection and limit of quantification of acrylamide were 0.2 ng x ml(-1) (6 fmol) and 0.8 ng x ml(-1) (22 fmol), respectively, by LC-MS/MS, and those of 2,3-dibromopropionamide derived from acrylamide were 12 ng x ml(-1) (52 fmol) and 40 ng x ml(-1) (170 fmol), respectively, by GC-MS. Repeatability given as RSD was <5 and <15% for the LC-MS/MS and GC-MS methods, respectively. High correlation (r(2) - 0.946) was observed between values obtained by the two methods. Most potato crisps and whole potato-based fried snacks showed acrylamide concentrations >1000 microg x kg(-1). The concentrations in non-whole potato-based snacks, rice crackers processed by grilling or frying, and candied sweet potatoes were lower compared with those in the potato crisps and the whole potato-based fried snacks. One of the whole potato-based fried snacks, however, showed low acrylamide concentration (<50 microg x kg(-1)) suggesting the formation of acrylamide is strongly influenced by processing conditions. Acrylamide concentrations in instant precooked noodles and won-tons were <100 microg x kg(-1) with only one exception. Roasted barley grains for 'Mugi-cha' tea contained 200-600 microg x kg(-1) acrylamide.

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Bacillus and Streptomyces species possess the ability to produce a variety of commercially important metabolites and extracellular enzymes. We previously demonstrated that antibiotic production in Streptomyces coelicolor A3(2) and Streptomyces lividans can be enhanced by RNA polymerase (RNAP) mutations selected for the rifampicin-resistant (Rif r ) phenotype. Here, we have shown that the introduction of a certain Rif r rpoB mutation into a B. subtilis strain resulted in cells that overproduce an aminosugar antibiotic 3,3 -neotrehalosadiamine (NTD), the production of which is dormant in the wild-type strain. Mutational and recombinant gene expression analyses have revealed a polycistronic gene ntdABC (formally yhjLKJ) and a monocistronic gene ntdR (formally yhjM) as the NTD biosynthesis operon and a positive regulator for ntdABC, respectively. Analysis of transcriptional fusions to a lacZ reporter revealed that NTD acts as an autoinducer for its own biosynthesis genes via NtdR protein. Our results also showed that the Rif r rpoB mutation causes an increase in the activity of A -dependent promoters including ntdABC promoter. Therefore, we propose that unlike the wild-type RNAP, the mutant RNAP efficiently recognized the A -dependent promoters, resulting in the dramatic activation of the NTD biosynthesis pathway by an autoinduction mechanism.The ability of bacteria to survive in a wide range of adverse environmental conditions depends on diverse molecular mechanisms that adjust gene expression pattern in response to changing environment. DNA-dependent RNA polymerase (RNAP), 1 which is composed of an essential catalytic core enzyme (␣ 2 ␤␤Ј ) and one of the sigma ( ) factors, is the central enzyme for expression of genomic information in all organisms.Rifampicin (Rif) inhibits transcription initiation by blocking the ␤ subunit of bacterial RNAP (1, 2). Many Rif-resistant (Rif r ) mutants have been isolated and characterized in various bacteria, notably Escherichia coli. To our knowledge, most Rif r mutations are found within the rpoB gene that encodes the ␤ subunit of RNAP (3-6). E. coli Rif r rpoB mutations that suppress the auxotrophy due to lack of stringent response were demonstrated to affect the transcription of stringently controlled genes by destabilizing the RNAP-stable RNA promoter complex (7). Recently, we successfully activated the secondary metabolism (antibiotic production) by introducing certain Rif r rpoB mutations in Streptomyces coelicolor A3(2) and Streptomyces lividans (8 -11). On the basis of those findings, we proposed that improvement of RNAP by introduction of a Rif r mutation can be useful to elicit bacterial ability by altering the gene expression in a variety of microorganisms.The members of the genus Bacillus produce several antibiotics to inhibit growth of the competing organisms in nature. Neotrehalosadiamine (3,3Ј-diamino-3,3Ј-dideoxy-␣,␤-trehalose; NTD), which is an aminosugar antibiotic produced by Bacillus pumilus (12) and Bacillus circulans (13), inhibits growth of Staphylococcus a...

Fe-6mass%Ni-(0.0008ϳ0.29)mass%C alloys were hot-deformed in torsion at 600-720°C (above the cooling transformation start temperatures A r3 ) after austenitization. An in-situ X-ray diffraction study revealed that g→a transformation occurred during deformation in a wide range of condition, even above A 3 p (paraequilibrium g→a transformation temperature). Corresponding to this transformation, apparent decrease in deformation stress from that expected for austenite was observed. Microstructural study of the specimens quenched after the deformation showed that a large amount of fine-grained ferrite was formed due to the deformation. The analysis of deformation stress and chemical driving-force of the transformation indicated that the transformation occurred in order to reduce the total energy of deformed material since the deformation of energy of a was revealed to be considerably smaller than that of g and the amount of deformation energy saved by the transformation was shown to be much greater than the chemical energy consumed by the transformation at the tested temperatures.KEY WORDS: low carbon steels; nickel steels; hot deformation; grain refinement; thermomechanical heat treatment; strain-induced transformation. study during hot deformation has been undertaken in low carbon Fe-Ni alloys. The in-situ X-ray diffraction technique had been successfully applied to find dynamic recrystallization of aluminum. 7) The experimental results of the in-situ X-ray study have been already reported. [8][9][10] This report puts together all the results of the in-situ X-ray study done in these reports and also includes the results of deformation stress measurement and microstructural study. In the deformation stress measurement, it was aimed to determine the difference in deformation stress between g and a more accurately. The cause of DT will then be discussed on the basis of these three kinds of experimental results. Experimental MaterialsThe compositions of the alloys used in this study are shown in Table 1. Nickel was added to reduce transformation temperature so as to make high temperature X-ray studies easier. It also enhances the hardenability of the alloys. Table 2 gives the transformation temperatures of the alloys. Equilibrium transformation temperatures were calculated by using Thermo-Calc. In this alloy system transformation during cooling was known to start from their paraequilibrium transformation start temperature, A 3 p , 11) not from orthoequilibrium transformation start temperature, A o 3 . Experimental cooling transformation start temperatures, A r3 , and transformation heating finish temperatures, A c3 , and a martensite start temperature, Ms, were adopted from preceding work, 12) in which alloys of the compositions close to the present ones were used. The alloys were vacuum-melted and hot-rolled to 3-mm thick plates. They were sliced and drawn into wires of 2-mm diameter, which were cut to 42 mm in length for torsion test. Apparatus and ProceduresThe schematic setup of X-ray diffraction experiment during t...

To clarify the effects of storage temperature on potato components and acrylamide in chips, tubers from five cultivars were stored at various temperatures (2, 6, 8, 10, and 18 C) for 18 weeks, and the contents of sugars, free amino acids in tubers, and acrylamide in chips after frying were analyzed. At temperatures lower than 8 C, the contents of reducing sugars increased markedly in all cultivars, with similar increases in the acrylamide level and dark brown chip color. Free amino acids showed little change at the storage temperatures tested and varied within certain ranges characteristic of each cultivar. The contents of reducing sugars correlated well with the acrylamide level when the fructose/asparagine molar ratio in the tubers was <2. When the fructose/ asparagine ratio was >2 by low-temperature storage, the asparagine content, rather than the reducing sugar content, was found to be the limiting factor for acrylamide formation.