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131.
We studied the transforming ability of the extracellular plasmid DNA released from a genetically engineered Escherichia coli pEGFP and the culturing conditions for the release of transforming DNA. The transforming ability was evaluated by transformation of competent cells with filtrates of E. coli pEGFP cultures. The number of transformants increased with time when E. coli pEGFP cells grew exponentially in rich medium, but not in stationary phase or when inoculated in freshwater. These results suggested that crude extracellular plasmid DNA had transforming ability and this transforming DNA was mainly released by actively growing bacteria. 相似文献
132.
Kimura K Kumar Rai S Takemasa K Ishibashi Y Kawabata M Belosevic M Uga S 《FEMS microbiology letters》2004,238(1):263-266
Cyclospora cayetanensis oocysts in the feces of humans from Kathmandu, Nepal were identified on the basis of their size and other morphological characteristics. We compared the detection of C. cayetanensis oocysts in the feces using three microscopic techniques such as formalin-ether sedimentation, sucrose centrifugal floatation, and direct smear. Standard procedures were used for the formalin-ether sedimentation and the sucrose centrifugal floatation techniques using 0.5 g of feces, however, the direct smear technique was performed using 10 microl of fecal suspension (0.005 g of feces) and observed under the fluorescent microscope. Of the 403 samples examined, 21 samples were positive for oocysts by all three techniques. Therefore, in these 21 samples, the number of oocysts recovered by the three techniques were compared. The highest number of oocyst was obtained by the sucrose centrifugal floatation technique. In contrast, the formalin-ether sedimentation technique was found to be the least reliable concentration technique for the detection of Cyclospora in human feces. Surprisingly, the direct smear technique was found to be an effective and rapid technique for diagnosis of C. cayetanensis making it a technique of choice for routine epidemiological investigation of the prevalence of this infection in human populations. 相似文献
133.
Hida AI Kawabata T Minamiyama Y Mizote A Okada S 《Free radical biology & medicine》2003,34(11):1426-1434
We investigated the effects of iron on the production of nitric oxide (NO), inducible NO synthase (iNOS), and plasma cytokines induced by lipopolysaccharide (LPS) in vivo. Male Wistar rats were preloaded with a single intravenous injection of saccharated colloidal iron (Fesin, 70 mg iron/kg body weight) or normal saline as a control, and then given an intraperitoneal injection of LPS (5.0 mg/kg body weight). Rats, preloaded with iron, had evidence of both iron deposition and strong iNOS induction in liver Kupffer cells upon injection of LPS; phagocytic cells in the spleen and lung had similar findings. LPS-induced NO production in iron-preloaded rats was significantly higher than control rats as accessed by NO-hemoglobin levels measured by ESR (electron spin resonance) and NOx (nitrate plus nitrite) levels. Western blot analysis showed that iron preloading significantly enhanced LPS-induced iNOS induction in the liver, but not in the spleen or lung. LPS-induced plasma levels of IL-6, IL-1beta, and TNF-alpha were also significantly higher in iron-preloaded rats as shown by ELISA, but IFN-gamma levels were unchanged. We conclude that colloidal-iron phagocytosed by liver Kupffer cells enhanced LPS-induced NO production in vivo, iNOS induction in the liver, and release of IL-6, IL-1beta, and TNF-alpha. 相似文献
134.
135.
On a possible evolutionary link of the stomochord of hemichordates to pharyngeal organs of chordates
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Noriyuki Satoh Kunifumi Tagawa Christopher J. Lowe Jr‐Kai Yu Takeshi Kawashima Hiroki Takahashi Michio Ogasawara Marc Kirschner Kanako Hisata Yi‐Hsien Su John Gerhart 《Genesis (New York, N.Y. : 2000)》2014,52(12):925-934
As a group closely related to chordates, hemichordate acorn worms are in a key phylogenic position for addressing hypotheses of chordate origins. The stomochord of acorn worms is an anterior outgrowth of the pharynx endoderm into the proboscis. In 1886 Bateson proposed homology of this organ to the chordate notochord, crowning this animal group “hemichordates.” Although this proposal has been debated for over a century, the question still remains unresolved. Here we review recent progress related to this question. First, the developmental mode of the stomochord completely differs from that of the notochord. Second, comparison of expression profiles of genes including Brachyury, a key regulator of notochord formation in chordates, does not support the stomochord/notochord homology. Third, FoxE that is expressed in the stomochord‐forming region in acorn worm juveniles is expressed in the club‐shaped gland and in the endostyle of amphioxus, in the endostyle of ascidians, and in the thyroid gland of vertebrates. Based on these findings, together with the anterior endodermal location of the stomochord, we propose that the stomochord has evolutionary relatedness to chordate organs deriving from the anterior pharynx rather than to the notochord. genesis 52:925–934, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
136.
Sumire Ishida Ryosuke Tanaka Naoya Yamaguchi Genki Ogata Takeomi Mizutani Kazushige Kawabata Hisashi Haga 《PloS one》2014,9(8)
Lumen formation is important for morphogenesis; however, an unanswered question is whether it involves the collective migration of epithelial cells. Here, using a collagen gel overlay culture method, we show that Madin-Darby canine kidney cells migrated collectively and formed a luminal structure in a collagen gel. Immediately after the collagen gel overlay, an epithelial sheet folded from the periphery, migrated inwardly, and formed a luminal structure. The inhibition of integrin-β1 or Rac1 activity decreased the migration rate of the peripheral cells after the sheets folded. Moreover, lumen formation was perturbed by disruption of apical-basolateral polarity induced by transforming growth factor-β1. These results indicate that cell migration and cell polarity play an important role in folding. To further explore epithelial sheet folding, we developed a computer-simulated mechanical model based on the rigidity of the extracellular matrix. It indicated a soft substrate is required for the folding movement. 相似文献
137.
Kenji Nakayama Takahiro Inoue Sadanori Sekiya Naoki Terada Yu Miyazaki Takayuki Goto Shigeki Kajihara Shin-Ichiro Kawabata Shinichi Iwamoto Kuniko Ikawa Junko Oosaga Hiroaki Tsuji Koichi Tanaka Osamu Ogawa 《PloS one》2014,9(9)
Background and Objectives
Prostate cancer (PCa) is one of the most common cancers and leading cause of cancer-related deaths in men. Mass screening has been carried out since the 1990s using prostate-specific antigen (PSA) levels in the serum as a PCa biomarker. However, although PSA is an excellent organ-specific marker, it is not a cancer-specific marker. Therefore, the aim of this study was to discover new biomarkers for the diagnosis of PCa.Materials and Methods
We focused on urine samples voided following prostate massage (digital rectal examination [DRE]) and conducted a peptidomic analysis of these samples using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MSn). Urinary biomaterials were concentrated and desalted using CM-Sepharose prior to the following analyses being performed by MALDI-TOF/MSn: 1) differential analyses of mass spectra; 2) determination of amino acid sequences; and 3) quantitative analyses using a stable isotope-labeled internal standard.Results
Multivariate analysis of the MALDI-TOF/MS mass spectra of urinary extracts revealed a 2331 Da peptide in urine samples following DRE. This peptide was identified as a C-terminal PSA fragment composed of 19 amino acid residues. Moreover, quantitative analysis of the relationship between isotope-labeled synthetic and intact peptides using MALDI-TOF/MS revealed that this peptide may be a new pathognomonic biomarker candidate that can differentiate PCa patients from non-cancer subjects.Conclusion
The results of the present study indicate that the 2331 Da peptide fragment of PSA may become a new pathognomonic biomarker for the diagnosis of PCa. A further large-scale investigation is currently underway to assess the possibility of using this peptide in the early detection of PCa. 相似文献138.
Yuki Kobayashi Takafumi Shiga Toshio Shibata Miyuki Sako Katsumi Maenaka Takumi Koshiba Hikaru Mizumura Toshio Oda Shun-ichiro Kawabata 《The Journal of biological chemistry》2014,289(37):25987-25995
Factor C, a serine protease zymogen involved in innate immune responses in horseshoe crabs, is known to be autocatalytically activated on the surface of bacterial lipopolysaccharides, but the molecular mechanism of this activation remains unknown. In this study, we show that wild-type factor C expressed in HEK293S cells exhibits a lipopolysaccharide-induced activity equivalent to that of native factor C. Analysis of the N-terminal addition, deletion, or substitution mutants shows that the N-terminal Arg residue and the distance between the N terminus and the tripartite of lipopolysaccharide-binding site are essential factors for autocatalytic activation, and that the positive charge of the N terminus may interact with an acidic amino acid(s) of the molecule to convert the zymogen into an active form. Chemical cross-linking experiments indicate that the N terminus is required to form a complex of the factor C molecules in a sufficiently close vicinity to be chemically cross-linked on the surface of lipopolysaccharides. We propose a molecular mechanism of the autocatalytic activation of the protease zymogen on lipopolysaccharides functioning as a platform to induce specific protein-protein interaction between the factor C molecules. 相似文献
139.
Investigation of physicochemical form of uranium in sediment of brackish Lake Obuchi using sequential extraction procedure 总被引:1,自引:0,他引:1
The physicochemical form of uranium (238U) in the sediment of brackish Lake Obuchi was investigated using the standard procedures of sequential extraction. Approximately
60% to 70% of 238U was composed of the form bound to carbonates and iron (Fe)-manganese (Mn) oxides in silty sediments, whereas more than 50%
of 238U existed in the minerals of sandy sediments. The proportions of 238U bound to carbonates in the sediments of brackish Lake Obuchi were larger than those in fresh-water lake sediments. Most
of the uranium in the brackish lake sediment was considered to be mainly influenced by UO2(CO3)3
4− in seawater, judging from the fact that the 234U/ 238U activity ratios (1.13 to 1.16) of silty sediments were very close to that of seawater (1.14). The high correlation found
between the 238U concentration in the sediment and the amount of organic matter demonstrated that organic matter acts as a scavenger for
238U accumulation on the lake bottom.
Received: July 2, 1999 / Accepted: May 25, 2000 相似文献
140.
Fluctuations in the salinity and physicochemical characteristics of water quality were surveyed in brackish Lake Obuchi on
the Shimokita Peninsula in Aomori, Japan. The mean salinity in the surface layer in all regions of Lake Obuchi was about 10
psu, whereas in the basin region at depths of greater than 3 m it was 20 psu. Furthermore, all the year round the halocline
was formed at depths of 1–4 m. The maximum density gradient along a vertical axis in the center of the lake was observed at
depths of 1–2 m in summer and 2–4 m in spring and fall. The depth of the maximum density gradient fluctuated with the seasons.
In summer the water in the bottom layer was anoxic, and Fe, Mn, PO4
3−-P, and NH4
+-N supplied from the bottom sediment accumulated at high concentrations below the halocline. Thus, it was observed that the
transfer of substances between the layers above and below the barrier formed by the halocline is suppressed. Although Lake
Obuchi is small and shallow, the inflowing seawater easily resides, and a stable halocline readily forms because of the shape
of its basin, which suddenly deepens on the Pacific Ocean side.
Received: May 24, 1999 / Accepted: September 25, 1999 相似文献