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191.
Qun Dong Xuan Liu Jian Yao Xiaotang Dong Chao Ma Yuxia Xu Jinian Fang Kan Ding 《Phytochemistry》2010,71(11-12):1430-1437
A polysaccharide fraction, J6, was isolated from the hot-water extract of flowers of oleander Nerium indicum Mill., using ethanol precipitation, cetyltrimethylammonium bromide (CTAB) complexing, anion-exchange chromatography and gel permeation chromatography. J6 was found to contain l-rhamnose, l-arabinose, d-galactose, and d-galacturonic acid, in the ratio of 10.1:49.8:30.1:10.0. Its structure was investigated by methylation analysis, periodate oxidation, Smith degradation, partial acid hydrolysis, electrospray ionization mass spectrometry and NMR spectroscopic methods. It was found that J6 is an RG-I type polysaccharide, which contains a rhamnogalacturonan backbone, with various branches attached to O-4 of l-rhamnose. The branches probably involve (1 → 4)-β-d-galactan, branched l-arabino-(1 → 3)(1 → 6)-β-d-galactan, and (1 → 5)-α-l-arabinan. J6 stimulated NO production of macrophage RAW264.7 cells in a preliminary test. 相似文献
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Modulation of host DNA synthesis is essential for many viruses to establish productive infections and contributes to viral diseases. Human cytomegalovirus (HCMV), a large DNA virus, blocks host DNA synthesis and deregulates cell cycle progression. We report that pUL117, a viral protein that we recently identified, is required for HCMV to block host DNA synthesis. Mutant viruses in which pUL117 was disrupted, either by frame-shift mutation or by a protein destabilization-based approach, failed to block host DNA synthesis at times after 24 hours post infection in human foreskin fibroblasts. Furthermore, pUL117-deficient virus stimulated quiescent fibroblasts to enter S-phase, demonstrating the intrinsic ability of HCMV to promote host DNA synthesis, which was suppressed by pUL117. We examined key proteins known to be involved in inhibition of host DNA synthesis in HCMV infection, and found that many were unlikely involved in the inhibitory activity of pUL117, including geminin, cyclin A, and viral protein IE2, based on their expression patterns. However, the ability of HCMV to delay the accumulation of the mini-chromosome maintenance (MCM) complex proteins, represented by MCM2 and MCM4, and prevent their loading onto chromatin, was compromised in the absence of pUL117. When expressed alone, pUL117 slowed cell proliferation, delayed DNA synthesis, and inhibited MCM accumulation. Knockdown of MCM proteins by siRNA restored the ability of pUL117-deficient virus to block cellular DNA synthesis. Thus, targeting MCM complex is one mechanism pUL117 employs to help block cellular DNA synthesis during HCMV infection. Our finding substantiates an emerging picture that deregulation of MCM is a conserved strategy for many viruses to prevent host DNA synthesis and helps to elucidate the complex strategy used by a large DNA virus to modulate cellular processes to promote infection and pathogenesis. 相似文献
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196.
Analysis of gene-trap Ds rice populations in Korea 总被引:1,自引:0,他引:1
Park SH Jun NS Kim CM Oh TY Huang J Xuan YH Park SJ Je BI Piao HL Park SH Cha YS Ahn BO Ji HS Lee MC Suh SC Nam MH Eun MY Yi G Yun DW Han CD 《Plant molecular biology》2007,65(4):373-384
Insertional mutagen-mediated gene tagging populations have been essential resources for analyzing the function of plant genes.
In rice, maize transposable elements have been successfully utilized to produce transposant populations. However, many generations
and substantial field space are required to obtain a sufficiently sized transposant population. In rice, the japonica and
indica subspecies are phenotypically and genetically divergent. Here, callus cultures with seeds carrying Ac and Ds were used to produce 89,700 lines of Dongjin, a japonica cultivar, and 6,200 lines of MGRI079, whose genome is composed of
a mixture of the genetic backgrounds of japonica and indica. Of the more than 3,000 lines examined, 67% had Ds elements. Among the Ds-carrying lines, 81% of Dongjin and 63% of MGRI079 contained transposed Ds, with an average of around 2.0 copies. By examining more than 15,000 lines, it was found that 12% expressed the reporter
gene GUS during the early-seedling stage. GUS was expressed in root hairs and crown root initials at estimated frequencies
of 0.78% and 0.34%, respectively. The 5,271 analyzed Ds loci were found to be randomly distributed over all of the rice chromosomes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Sung Han Park, Nam Soo Jun, Chul Min Kim are contributed equally to this paper 相似文献
197.
Lesser EA Starr J Kong X Megerian JT Gozani SN 《Perspectives in biology and medicine》2007,50(1):40-53
Nerve conduction studies (NCS) and needle electromyography are useful and established diagnostic procedures for evaluating patients with signs and symptoms of neuromuscular disease. Although technological advances have occurred since the introduction of commercial electromyography instrumentation in the 1950s, most improvements have been evolutionary and were designed to benefit traditional users--neurologists and physiatrists specializing in electromyography. In the past seven years, instruments have been introduced that automate NCS and thereby enable a broader group of physicians, including internists and orthopedic surgeons, to perform these studies and utilize electromyographic data in the care of their patients. Automated NCS devices are an example of what Clayton Christensen terms a "disruptive innovation." In this article, automated NCS is contrasted with traditional electromyography, and the challenges and opposition to its widespread adoption are explored. 相似文献
198.
Park SH Kim CM Je BI Park SH Park SJ Piao HL Xuan YH Choe MS Satoh K Kikuchi S Lee KH Cha YS Ahn BO Ji HS Yun DW Lee MC Suh SC Eun MY Han CD 《Planta》2007,227(1):1-12
OSH6 (Oryza sativa Homeobox6) is an ortholog of lg3 (Liguleless3) in maize. We generated a novel allele, termed OSH6-Ds, by inserting a defective Ds element into the third exon of OSH6, which resulted in a truncated OSH6 mRNA. The truncated mRNA was expressed ectopically in leaf tissues and encoded the N-terminal region of OSH6, which includes
the KNOX1 and partial KNOX2 subdomains. This recessive mutant showed outgrowth of bracts or produced leaves at the basal node
of the panicle. These phenotypes distinguished it from the OSH6 transgene whose ectopic expression led to a “blade to sheath transformation” phenotype at the midrib region of leaves, similar
to that seen in dominant Lg3 mutants. Expression of a similar truncated OSH6 cDNA from the 35S promoter (35S::ΔOSH6) confirmed that the ectopic expression of this product was responsible for the aberrant bract development. These data suggest
that OSH6-Ds interferes with a developmental mechanism involved in bract differentiation, especially at the basal nodes of panicles.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
199.
While natural microbial biofilms often consist of multiple species, single-species biofilms are of great interest to biotechnology. The current study evaluates biofilm formation for common industrial and laboratory microorganisms. A total of 68 species of biosafety level one bacteria and yeasts from over 40 different genera and five phyla were screened by growing them in microtiter plates and estimating attached biomass by crystal violet staining. Most organisms showed biofilm formation on surfaces of polystyrene within 24 h. By changing a few simple conditions such as substratum characteristics, inoculum and nutrient availability, 66 strains (97%) demonstrated biofilm formation under at least one of the experimental conditions and over half of these strains were classified as strong biofilm formers, potentially suitable as catalysts in biofilm applications. Many non-motile bacteria were also strong biofilm formers. Biofilm morphologies were visualized for selected strains. A model organism, Zymomonas mobilis, easily established itself as a biofilm on various reactor packing materials, including stainless steel. 相似文献
200.
CLA differently regulates adipogenesis in stromal vascular cells from porcine subcutaneous adipose and skeletal muscle 总被引:2,自引:0,他引:2
Conjugated linoleic acid (CLA), a mixture of isomers of linoleic acid, has previously been shown to be able to decrease porcine subcutaneous (SC) adipose tissue levels while increasing the count of intramuscular (IM) adipose tissue in vivo. However, the underlying mechanisms through which it acts are poorly understood. The objective of this study was to investigate the different effects of CLA on adipogenesis in cultured SC adipose tissue and IM stromal vascular cells obtained from neonatal pigs. As shown here, trans-10, cis-12 CLA decreased the expression of adipocyte-specific genes as well as adipose precursor cell numbers and the accumulation of lipid in cultured SC adipose tissue stromal vascular cells. However, the cis-9, trans-11 CLA did not alter adipogenesis in SC cultures. On the other hand, both CLA isomers increased the expression of adipocyte-specific genes in IM cultures, together with the increasing accumulation of lipid and Oil Red O-stained cells. Collectively, these data show that CLA decreases SC adipose tissue but increases IM adipose tissue by different regulation of adipocyte-specific gene expression. These results suggest that adipogenesis in IM adipocytes differs from that in SC adipocytes. 相似文献