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61.
葡寡糖对LPS诱导小鼠氧化应激与炎症反应调节作用的研究 总被引:1,自引:0,他引:1
本文研究了低、中、高三种不同聚合度葡寡糖(LGOS、MGOS、HGOS)对小鼠氧化应激与炎症反应的调节,并探讨其可能的作用机制。在采食正常日粮基础上,各组小鼠每日分别灌胃生理盐水、低聚果糖(FOS)、LGOS、MGOS、HGOS。21 d后,腹腔注射脂多糖(LPS)诱导小鼠建立氧化应激与炎症反应模型,分别测定LPS刺激后4 h和18 h时血清和肝脏中活性氧(reactive oxygen species,ROS)水平、总抗氧化能力(total antioxidant ca-pacity,T-AOC)、过氧化氢酶(catalase,CAT)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)活性、丙二醛(Malondialdehyde,MDA)含量、肝脏中一氧化氮(NO)含量、一氧化氮合酶(nitric oxide synthase,NOS)活性、血清中白细胞介素1(Interleukin-1,IL-1)和肿瘤坏死因子(tumor necrosis factor,TNF-a)含量。结果表明:三种聚合度葡寡糖均能显著降低LPS刺激小鼠血清、肝脏中ROS水平(P<0.05),降低肝脏中NO含量、T-NOS、iNOS活性、血清中炎性细胞因子(IL-1、TNF-a)含量(P<0.05),显著提高总抗氧化能力(T-AOC)和抗氧化酶(CAT、GSH-Px)活性(P<0.05)。葡寡糖具有保护机体免受氧化损伤,减缓炎症反应的作用,并随着平均聚合度(degree ofpolymerization,DP)的增加,其调节功能逐渐增强。 相似文献
62.
Dalmais B Schumacher J Moraga J LE Pêcheur P Tudzynski B Collado IG Viaud M 《Molecular Plant Pathology》2011,12(6):564-579
The grey mould fungus Botrytis cinerea produces two major phytotoxins, the sesquiterpene botrydial, for which the biosynthesis gene cluster has been characterized previously, and the polyketide botcinic acid. We have identified two polyketide synthase (PKS) encoding genes, BcPKS6 and BcPKS9, that are up-regulated during tomato leaf infection. Gene inactivation and analysis of the secondary metabolite spectra of several independent mutants demonstrated that both BcPKS6 and BcPKS9 are key enzymes for botcinic acid biosynthesis. We showed that BcPKS6 and BcPKS9 genes, renamed BcBOA6 and BcBO9 (for B. cinerea botcinic acid biosynthesis), are located at different genomic loci, each being adjacent to other putative botcinic acid biosynthetic genes, named BcBOA1 to BcBOA17. Putative orthologues of BcBOA genes are present in the closely related fungus Sclerotinia sclerotiorum, but the cluster organization is not conserved between the two species. As for the botrydial biosynthesis genes, the expression of BcBOA genes is co-regulated by the Gα subunit BCG1 during both in vitro and in planta growth. The loss of botcinic acid production does not affect virulence on bean and tomato leaves. However, double mutants that do not produce botcinic acid or botrydial (bcpks6Δbcbot2Δ) exhibit markedly reduced virulence. Hence, a redundant role of botrydial and botcinic acid in the virulence of B. cinerea has been demonstrated. 相似文献
63.
Leaf longevity and nutrient resorption efficiency are important strategies to conserve plant nutrients. Theory suggests a negative relationship between them and also proposes that high concentration of phenolics in long‐lived leaves may reduce nutrient resorption. In order to provide new evidence on these relationships, we explored whether N‐resorption efficiency is related to leaf longevity, secondary compounds and other leaf traits in coexisting plant species of different life forms in the arid Patagonian Monte, Argentina. We assessed N‐resorption efficiency, green leaf traits (leaf mass per area (LMA), leaf longevity and lignin, total soluble phenolics and N concentrations) and N concentration in senescent leaves of 12 species of different life forms (evergreen shrubs, deciduous shrubs and perennial grasses) with contrasting leaf traits. We found that leaf longevity was positively correlated to LMA and lignin, and negatively correlated to N concentration in green leaves. N concentrations both in green and senescent leaves were positively related. N‐resorption efficiency was not associated with the concentration of secondary compounds (total soluble phenolics and lignin) but it was negatively related to LMA and leaf longevity and positively related to N concentration in green leaves. Furthermore, leaf traits overlapped among life forms highlighting that life forms are not a good indicator of the functional properties (at least in relation to nutrient conservation) of species. In conclusion, our findings indicated that differences in N‐resorption efficiency among coexisting species were more related to N concentration in green leaves, leaf lifespan and LMA than to the presence of secondary compounds at least those assessed in our study (soluble phenolics and lignin). Accordingly, N‐resorption efficiency seems to be modulated, at least in part, by the productivity–persistence trade‐off. 相似文献
64.
Reid BN LE M McCord WP Iverson JB Georges A Bergmann T Amato G Desalle R Naro-Maciel E 《Molecular ecology resources》2011,11(6):956-967
Molecular barcoding can serve as a powerful tool in wildlife forensics and may prove to be a vital aid in conserving organisms that are threatened by illegal wildlife trade, such as turtles (Order Testudines). We produced cytochrome oxidase subunit one (COI) sequences (650 bp) for 174 turtle species and combined these with publicly available sequences for 50 species to produce a data set representative of the breadth of the order. Variability within the barcode region was assessed, and the utility of both distance-based and character-based methods for species identification was evaluated. For species in which genetic material from more than one individual was available (n = 69), intraspecific divergences were 1.3% on average, although divergences greater than the customary 2% barcode threshold occurred within 15 species. High intraspecific divergences could indicate species with a high degree of internal genetic structure or possibly even cryptic species, although introgression is also probable in some of these taxa. Divergences between species of the same genus were 6.4% on average; however, 49 species were <2% divergent from congeners. Low levels of interspecific divergence could be caused by recent evolutionary radiations coupled with the low rates of mtDNA evolution previously observed in turtles. Complementing distance-based barcoding with character-based methods for identifying diagnostic sets of nucleotides provided better resolution in several cases where distance-based methods failed to distinguish species. An online identification engine was created to provide character-based identifications. This study constitutes the first comprehensive barcoding effort for this seriously threatened order. 相似文献
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Small interfering RNA (siRNA) and microRNA (miRNA) are small RNAs of 18-25 nucleotides (nt) in length that play important roles in regulating gene expression. They are incorporated into an RNA-induced silencing complex (RISC) and serve as guides for silencing their corresponding target mRNAs based on complementary base-pairing. The promise of gene silencing has led many researchers to consider siRNA as an anti-viral tool. However, in long-term settings, many viruses appear to escape from this therapeutical strategy. An example of this may be seen in the case of human immunodeficiency virus type-1 (HIV-1) which is able to evade RNA silencing by either mutating the siRNA-targeted sequence or by encoding for a partial suppressor of RNAi (RNA interference). On the other hand, because miRNA targeting does not require absolute complementarity of base-pairing, mutational escape by viruses from miRNA-specified silencing may be more difficult to achieve. In this review, we discuss stratagems used by various viruses to avoid the cells' antiviral si/mi-RNA defenses and notions of how viruses might control and regulate host cell genes by encoding viral miRNAs (vmiRNAs). 相似文献
68.
A relatively new intravenous opaque medium, Hypaque(R) in 50 per cent solution, was used in 50 consecutive patients. None of them had a serious reaction. Twenty-two had mild reactions which were of no clinical significance. The radiographs obtained seemed to be equal in quality to those obtained with other contrast media. 相似文献
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