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1.
Variants of NOD2, an intracellular sensor of bacteria-derived muramyl dipeptide (MDP), increase susceptibility to Crohn's disease (CD). These variants are thought to be defective in activation of nuclear factor kappaB (NF-kappaB) and antibacterial defenses, but CD clinical specimens display elevated NF-kappaB activity. To illuminate the pathophysiological function of NOD2, we introduced such a variant to the mouse Nod2 locus. Mutant mice exhibited elevated NF-kappaB activation in response to MDP and more efficient processing and secretion of the cytokine interleukin-1beta (IL-1beta). These effects are linked to increased susceptibility to bacterial-induced intestinal inflammation and identify NOD2 as a positive regulator of NF-kappaB activation and IL-1beta secretion.  相似文献   
2.
MytiLec; a novel lectin isolated from the Mediterranean mussel (Mytilus galloprovincialis); shows strong binding affinity to globotriose (Gb3: Galα1-4Galβ1-4Glc). MytiLec revealed β-trefoil folding as also found in the ricin B-subunit type (R-type) lectin family, although the amino acid sequences were quite different. Classification of R-type lectin family members therefore needs to be based on conformation as well as on primary structure. MytiLec specifically killed Burkitt''s lymphoma Ramos cells, which express Gb3. Fluorescein-labeling assay revealed that MytiLec was incorporated inside the cells. MytiLec treatment of Ramos cells resulted in activation of both classical MAPK/ extracellular signal-regulated kinase and extracellular signal-regulated kinase (MEK-ERK) and stress-activated (p38 kinase and JNK) Mitogen-activated protein kinases (MAPK) pathways. In the cells, MytiLec treatment triggered expression of tumor necrosis factor (TNF)-α (a ligand of death receptor-dependent apoptosis) and activation of mitochondria-controlling caspase-9 (initiator caspase) and caspase-3 (activator caspase). Experiments using the specific MEK inhibitor U0126 showed that MytiLec-induced phosphorylation of the MEK-ERK pathway up-regulated expression of the cyclin-dependent kinase inhibitor p21, leading to cell cycle arrest and TNF-α production. Activation of caspase-3 by MytiLec appeared to be regulated by multiple different pathways. Our findings, taken together, indicate that the novel R-type lectin MytiLec initiates programmed cell death of Burkitt’s lymphoma cells through multiple pathways (MAPK cascade, death receptor signaling; caspase activation) based on interaction of the lectin with Gb3-containing glycosphingolipid-enriched microdomains on the cell surface.  相似文献   
3.
To assess the possible utility of a fungal gene for manganese-dependent peroxidase (MnP) produced by a transgenic plant in phytoremediation, we transformed hybrid aspen with a chimeric gene for MnP. Our gene construct allowed expression of the gene for MnP in plants and relatively high MnP activity was detected in the hydroponic medium in which roots of plants that expressed the transgene had been cultured. Some of our transgenic plants were able to remove bisphenol A from the medium more efficiently than wild-type plants. Our results demonstrate that, without any modification of the coding sequence, a chimeric gene for fungal MnP can be expressed in a woody plant, with secretion of active MnP from roots into the rhizosphere. Our strategy suggests new options using woody plants for phytoremediation.  相似文献   
4.
We investigated the optical absorption properties (A 400/C and A 600/C values), elemental composition, weight-averaged molecular weight (Mw), and liquid-state carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy of DAX-8 adsorbed fulvic acid fractions (DAX-8 FAs) in various soils (n?=?36) to establish the general trends in their chemical characteristics. We also compared our results with those of humic acids (HAs) obtained from the same soils used in this study and other published data to discuss the differences between them. Our results clearly indicate that DAX-8 FAs with high carboxyl C content have small Mw and low hydrogen to carbon (H/C) ratio. In addition, DAX-8 FAs with high carbonyl C and alkyl C content have high A 400/C values and H/C ratios, respectively. These results strongly suggest that DAX-8 FAs with high aliphatic chemical properties have low carboxyl C content, large Mw and high H/C ratio. There are significant differences in chemical characteristics among the various soil types in almost all data; e.g., DAX-8 FAs from Podzols showed significantly higher A 400/C values, larger Mw, higher carbonyl C and O-aryl C content than those obtained from Andosols. However, these two C functional groups are relatively low values in the total C content among all soil types, suggesting that DAX-8 FAs may exhibit only small differences in chemical properties among the various soil types. The comparison with published data regarding soil HAs shows that DAX-8 FAs are characterized by smaller Mw; lower C, H, and nitrogen (N); higher oxygen (O) content; higher O/C; lower O/H ratios; higher carboxyl C content; and lower aryl C content in total C.  相似文献   
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6.
It is universally accepted that grassland soils have a good crumb structure, and the aggregation of soil particles is mainly attributed to the organic matter supplied from grass roots, and to certain organic aggregating agents accumulated in the decomposition process.  相似文献   
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8.
Introduction

Phosphorus applied on a phosphate deficient soil, by increasing the root development of the plant, or by stimulating the soil microflora especially in the rhizosphere, may increase the amount of phosphorus which the plant takes up from the soil. This present paper is a report on a pot culture investigation of such an effect of added phosphorus.  相似文献   
9.
Laccases play important roles in the development of fruiting bodies and in lignin degradation by basidiomycetes. In this study, we present novel phenotypes of transgenic tobacco plants with a chimeric gene for fungal laccase under the control of the cauliflower mosaic virus 35S promoter. At the flowering stage, the transgenic plants that produced recombinant laccase had brownish anthers instead of the greenish anthers of wild-type plants. The brownish anthers exhibited male sterility with a nondehiscent phenotype at varying frequencies. The frequency of nondehiscence depended on the temperature at which plants were cultivated and it was higher at 24°C than at 29°C. The cell wall structures of transgenic anther tissues were almost the same as in the wild type, but the stomium was severely deformed, and abnormal components were apparent in cells of the endothecium and epidermis. Furthermore, the pattern of deposition of flavonoids in the transgenic anther epidermis differed from the wild-type pattern. The expression of laccase also induced other phenotypic changes in the flowers of transgenic plants, namely, increased petal number, fused and petaloid stamens, and doubling of floral organs. These results indicate that the ectopic expression of laccase influences various aspects of flower development.  相似文献   
10.
Introduction

As a result of the H-bomb explosion tests of the U.S.A. in the Southern Pacific Ocean, rain-out in Japan is contaminated considerably by fission products, and field crops also show apparently artificial radioactivities. Many workers are now investigating to clarify degree and regional extent of contamination or sorts of radioactive elements.  相似文献   
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