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991.
Determination of glyphosate, glyphosate metabolites, and glufosinate in human serum by gas chromatography-mass spectrometry 总被引:2,自引:0,他引:2
Motojyuku M Saito T Akieda K Otsuka H Yamamoto I Inokuchi S 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2008,875(2):509-514
This paper describes an assay for the determination of glyphosate (GLYP), glyphosate metabolites [(aminomethyl) phosphonic acid] (AMPA), and glufosinate (GLUF) in human serum. After protein precipitation using acetonitrile and solid-phase extraction, serum samples were derivatized and analyzed by gas chromatography-mass spectrometry (GC-MS). The assay was linear over a concentration range of 3-100.0 microg/ml for GLYP, AMPA, and GLUF. The overall recoveries for the three compounds were >73%. The intra- and inter-day variations were <15%. Precision and accuracy were 6.4-10.6% and 88.2-103.7%, respectively. The validated method was applied to quantify the GLYP and AMPA content in the serum of a GLYP-poisoned patient. In conclusion, the method was successfully applied for the determination of GLYP and its metabolite AMPA in serum obtained from patient of GLYP-poisoning. 相似文献
992.
Kawaguchi M Ito R Honda H Endo N Okanouchi N Saito K Seto Y Nakazawa H 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2008,875(2):577-580
We have developed an analytical method for the determination of urinary 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan), which utilizes stir bar sorptive extraction (SBSE) and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). Human urine sample is de-conjugated by treatment with beta-glucuronidase and sulfatase. A stir bar coated with polydimethylsiloxane (PDMS) is added to the urine sample in a vial and the sample is stirred for 60 min at room temperature (25 degrees C). Then, the PDMS stir bar is subjected to TD-GC-MS. The detection limit of triclosan is 0.05 ng mL(-1). The method shows linearity over the calibration range (0.1-10 ng mL(-1)) and the correlation coefficient (r) is higher than 0.993 for triclosan standard solution. The average recoveries of triclosan in human urine sample are 102.8-113.1% (RSD: 2.4-6.7%). This simple, sensitive, and selective analytical method may be used in the determination of trace amounts of triclosan in human urine samples. 相似文献
993.
Plants produce a variety of secondary metabolites to protect themselves from pathogens and herbivores and/or to influence
the growth of neighbouring plants. Some of these metabolites are toxic to the producing cells when their target sites are
present in the producing organisms. Therefore, a specific self-resistance mechanism must exist in these plants. Self-resistance
mechanisms, including extracellular excretion, vacuolar sequestration, vesicle transport, extracellular biosynthesis, and
accumulation of the metabolite in a non-toxic form, have been proposed thus far. Recently, a new mechanism involving mutation
of the target protein of the toxic metabolite has been elucidated. We review here the mechanisms that plants use to prevent
self-toxicity from the following representative compounds: cannabinoids, flavonoids, diterpene sclareol, alkaloids, benzoxazinones,
phenylpropanoids, cyanogenic glycosides, and glucosinolates. 相似文献
994.
Søren Bak Susanne Michelle Paquette Marc Morant Anne Vinther Morant Shigeki Saito Nanna Bjarnholt Mika Zagrobelny Kirsten Jørgensen Sarah Osmani Thomas Hamann Henrik Toft Simonsen Raquel Sanchez Pérez Torbjørn Bordier van Heeswijck Bodil Jørgensen Birger Lindberg Møller 《Phytochemistry Reviews》2008,7(1):209-209
995.
Hiroki Nishimura Gen Komaki Tetsuya Ando Toshihiro Nakahara Takakazu Oka Keisuke Kawai Toshihiko Nagata Aya Nishizono Yuri Okamoto Kenjiro Okabe Masanori Koide Chikara Yamaguchi Satoshi Saito Kazuyoshi Ohkuma Katsutaro Nagata Tetsuro Naruo Masato Takii Nobuo Kiriike Toshio Ishikawa 《BioPsychoSocial medicine》2008,2(1):1-8
Background
Over the last five to ten years there has been an increase in psychosomatic complaints (PSC) in Swedish children. The objective of the study was to examine the relation between PSC and sense of coherence (SOC). 相似文献996.
997.
Kihara AH Paschon V Akamine PS Saito KC Leonelli M Jiang JX Hamassaki DE Britto LR 《Developmental neurobiology》2008,68(11):1287-1302
Gap junction (GJ) channels couple adjacent cells, allowing transfer of second messengers, ions, and molecules up to 1 kDa. These channels are composed by a multigene family of integral membrane proteins called connexins (Cx). In the retina, besides being essential circuit element in the visual processing, GJ channels also play important roles during its development. Herein, we analyzed Cx43, Cx45, Cx50, and Cx56 expression during chick retinal histogenesis. Cx exhibited distinct expression profiles during retinal development, except for Cx56, whose expression was not detected. Cx43 immunolabeling was observed at early development, in the transition of ventricular zone and pigmented epithelium. Later, Cx43 was seen in the outer plexiform and ganglion cell layers, and afterwards also in the inner plexiform layer. We observed remarkable changes in the phosphorylation status of this protein, which indicated modifications in functional properties of this Cx during retinal histogenesis. By contrast, Cx45 showed stable gene expression levels throughout development and ubiquitous immunoreactivity in progenitor cells. From later embryonic development, Cx45 was mainly observed in the inner retina, and it was expressed by glial cells and neurons. In turn, Cx50 was virtually absent in the chick retina at initial embryonic phases. Combination of PCR, immunohistochemistry and Western blot indicated that this Cx was present in differentiated cells, arising in parallel with the formation of the visual circuitry. Characterization of Cx expression in the developing chick retina indicated particular roles for these proteins and revealed similarities and differences when compared to other species. 相似文献
998.
Ex vivo hematopoiesis from embryonic sources offers exciting promises in basic research and medicine. In this issue of Cell Stem Cell, Ledran et al. (2008) describe human embryonic stem cell (hESC)-derived hematopoiesis, while Taoudi et al. (2008) define the origin of definitive hematopoietic stem cells (HSCs) from the mouse aorta-gonad-mesonephros (AGM) region. 相似文献
999.
Matsunaga I Naka T Talekar RS McConnell MJ Katoh K Nakao H Otsuka A Behar SM Yano I Moody DB Sugita M 《The Journal of biological chemistry》2008,283(43):28835-28841
Trehalose dimycolate (TDM), also known as cord factor, is a major surface glycolipid of the cell wall of mycobacteria. Because of its potent biological functions in models of infection, adjuvancy, and immunotherapy, it is important to determine how its biosynthesis is regulated. Here we show that glucose, a host-derived product that is not readily available in the environment, causes Mycobacterium avium to down-regulate TDM expression while up-regulating production of another major glycolipid with immunological roles in T cell activation, glucose monomycolate (GMM). In vitro, the mechanism of reciprocal regulation of TDM and GMM involves competitive substrate selection by antigen 85A. The switch from TDM to GMM biosynthesis occurs near the physiological concentration of glucose present in mammalian hosts. We further demonstrate that GMM is produced in vivo by mycobacteria growing in mouse lung. These results establish an enzymatic pathway for GMM production. More generally, these observations provide a specific enzymatic mechanism for dynamic alterations of cell wall glycolipid remodeling in response to the transition from noncellular to cellular growth environments, including factors that are monitored by the host immune system. 相似文献
1000.
Kagawa W Kagawa A Saito K Ikawa S Shibata T Kurumizaka H Yokoyama S 《The Journal of biological chemistry》2008,283(35):24264-24273
Rad52 plays essential roles in homology-dependent double-strand break repair. Various studies have established the functions of Rad52 in Rad51-dependent and Rad51-independent repair processes. However, the precise molecular mechanisms of Rad52 in these processes remain unknown. In the present study we have identified a novel DNA binding site within Rad52 by a structure-based alanine scan mutagenesis. This site is closely aligned with the putative single-stranded DNA binding site determined previously. Mutations in this site impaired the ability of the Rad52-single-stranded DNA complex to form a ternary complex with double-stranded DNA and subsequently catalyze the formation of D-loops. We found that Rad52 introduces positive supercoils into double-stranded DNA and that the second DNA binding site is essential for this activity. Our findings suggest that Rad52 aligns two recombining DNA molecules within the first and second DNA binding sites to stimulate the homology search and strand invasion processes. 相似文献