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排序方式: 共有112条查询结果,搜索用时 62 毫秒
1.
DAVEY M. R.; MULLIGAN B. J.; GARTLAND K. M. A.; PEEL E.; SARGENT A. W.; MORGAN A. J. 《Journal of experimental botany》1987,38(9):1507-1516
Davey, M. R., Mulligan, B. J., Gartland, K. M. A., Peel, E.,Sargent, A. W. and Morgan, A. J. 1987. Transformation of Solanumand Nicotiana species using an Ri plasmid vector.J. exp.Bot. 38: 15071516. Five Nicotiana species (N. benthemiana, N. debneyi, N. occidentals,N. plumbaginifolia, N. tabacum) and three Solanum species (S.dulcamara, S. nigrum, S. tuberosum) were transformed by wild-typeand engineered Ri plasmids. Depending on the host plant, rootstransformed by Agrobacterium strain A4TIII with an Ri plasmidcarrying a chimaeric nopaline synthase-kanamycin resistancegene, were 3 to 40 times more resistant to kanamycin than rootstransformed by the wild-type plasmid of strain A4T. Similarly,plants regenerated from A4TIII-derived roots of N. debneyi,N. plumbaginifolia and N. tabacum were 8 to 16 times more resistantthan A4T plants, and survived at 400 µg cm3 of kanamycin.A4TIII plants of S. nigrum flowered in vitro at 6001000µg cm3 of kanamycin. Transformed roots and most regeneratedplants synthesized Ri-speciflc opines, while DNA hybridizationconfirmed the presence of DNA homologous to that from wild-typeand engineered Ri plasmids in transformed plants of S. nigrum. Key words: Agrobacterium, Ri plasmid, transformed roots, plant regeneration, kanamycin resistance. 相似文献
2.
Changes in nitrogenase activity (C2H2 reduction and H2 production),nodulated root respiration and the efficiency of nitrogenasefunctioning were measured in response to progressive dehydrationof nodules on intact well-watered plants of subterranean clover(Trifolium subterraneum L.) cv. Seaton Park. The nodulated rootsof vegetative plants grown to the 14-leaf stage were incubatedin a gas exchange system through which a continuous dry airstreamwas passed over an 8 d period. The root tips were immersed inan N-free nutrient solution during this time so that water andion uptake was unimpeded. The decline in nodulated root respirationresulting from nodule drying was associated with a continualreduction in respiration coupled to nitrogenase activity. Asnodule water potential (nod) decreased, the proportion of totalnodulated root respiration which was nitrogenase-linked declinedfrom 50% (day 1) to 33% (day 8). This was accompanied by a 79%reduction in specific nitrogenase activity (from 3.79 to 0.81umol C2H4 g1 nodule dry weight min1). Nodule dehydrationalso induced a decline in hydrogen (H2) production in air. Therelative decline in hydrogen production exceeded that of acetylenereduction activity and this resulted in an increase in the relativeefficiency of nitrogenase functioning. However, the carbon costof nitrogenase activity progressively increased above 2.0 molCO2 respired per mol C2H4 reduced as rood decreased below 0.4to 0.5 MPa. Consecutive measurements of the rates ofhydrogen evolution, 15N2 fixation and acetylene reduction activityon intact unstressed plants resulted in a C2H4/N2 conversionfactor of 4.08 and an electron balance of 1.08. These resultsindicated that the pre-decline rate of acetylene reduction activitymeasured in a flow-through system provided a valid measure ofthe total electron flux through nitrogenase. Key words: Subterranean clover, dehydration, efficiency, nitrogenase activity 相似文献
3.
The effects of the trichothecene mycotoxins (acetyl T-2 toxin, T-2 toxin, HT-2 toxin, palmityl T-2 toxin, diacetoxyscirpenol (DAS), deoxynivalenol (DON), and T-2 tetraol) on bovine platelet function were examined in homologous plasma stimulated with platelet activating factor (PAF). The mycotoxins inhibited platelet function with the following order of potency: acetyl T-2 toxin > palmityl T-2 toxin = DAS > HT-2 toxin = T-2 toxin. While T-2 tetraol was completely ineffective as an inhibitor, DON exhibited minimal inhibitory activity at concentrations above 10×10?4M. The stability of the platelet aggregates formed was significantly reduced in all mycotoxin treated platelets compared to that of the untreated PAF controls. It is suggested that the increased sensitivity of PAF stimulated bovine platelets to the more lipophilic mycotoxins may be related to their more efficient partitioning into the platelet membrane compared to the more hydrophilic compounds. 相似文献
4.
Nuclei were isolated from cotyledons of a range of accessionsfrom 14 species of Glycine. These were stained with ethidiumbromide and the relative fluorescence for each genotype wasmeasured by flow cytometry. The DNA content was estimated bycomparison of relative fluorescence with that from nuclei fromseedling leaves of Allium cepa, whose DNA content has been calculatedpreviously by chemical assay. The 4C amounts for diploid Glycineranged from 3.80 to 6.59 pg. Two groups of diploid species appearedfrom the analysis. The first consisted of species with amountsranging from 3.80 to 5.16 pg and included G. canescens (AA),G. argyrea (A1 A1), G. clandestina (A2A2), G. microphylla(BB),G. latifolia (B1B1), G. tabacina 2n=40 (B2B2), G. tomentella2n=38 (EE) and 2n=40 (DD), G. max and G. soja (GG), G. arenariaand G. latrobeana. A second group had higher DNA contents rangingfrom 5.27 to 6.59 pg, and consisted of G. curvata, G. cyrtoloba(CC), and G. falcata (FF). The polyploid species, G. tabacina2n=80 (AABB, BBB1B1), G. tomentella 2n=78 and 2n=80 (AAEE andDDEE, respectively) contained amounts approximating to the sumsof the respective parental diploid species thought to have givenrise to these allotetraploids. Intraspecific variation was detectedin the DNA content of G. canescens. Within the overall distributionof DNA amounts found in A genome species, each genome containeda range of DNA contents specific to that species. This phenomenonwas also detected amongst B genome species. 相似文献
5.
目的:探讨280例胃食管反流病(GERD)的分布特点及危险因素。方法:对临床诊断和胃镜确诊的280例GERD患者进行临床和风险因子相关性分析。结果:不论汉族还是维族,男性患者比例均明显高于女性;汉族患者高发年龄段早于维族患者(z=-2.939,P=0.003,);汉族和维族患者占反流性食管炎和Barrett食管比例分别为42.4%、81_3%及56.5%、18.8%,其中汉族患者Barrett食管比例较高(X2=14.358,P=0.000);肥胖、习惯性便秘、重体力活动者、饮食习惯不良在维族患者中的比例较高(P〈0.001)。结论:GERD与性别、年龄密切相关,男性多于女性,汉族患者发病年龄高峰旱于维族患者;汉族患者Barrett食管发生比例高于维族患者;肥胖、习惯性便秘、重体力活动、饮食习惯不良可能是GERD尤其是维族人群GERD的危险因素。 相似文献
6.
Jolanda?HM?van Bilsen Josée?PA?Wagenaar-Hilbers Maarten?JF?van der Cammen Mariska?EA?van Dijk Willem?van Eden Marca?HM?WaubenEmail author 《Arthritis research & therapy》2002,4(4):R2
We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental
arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the
course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration
of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the
MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP
peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development
of such therapies. 相似文献
7.
Characterization of terminal NeuNAcalpha2-3Galbeta1-4GlcNAc sequence in lipooligosaccharides of Neisseria meningitidis 总被引:1,自引:0,他引:1
Group B and C Neisseria meningitidis are the major cause of meningococcal
disease in the United States and in Europe. N . meningitidis
lipooligosaccharide (LOS), a major surface antigen, can be divided into 12
immunotypes of which L1 through L8 were found among Group B and C
organisms. Groups B and C but not Group A may sialylate their LOSs with
N-acetylneuraminic acid (NeuNAc) at the nonreducing end because they
synthesize CMP-NeuNAc. Using sialic acid-galactose binding lectins as
probes in an ELISA format, six of the eight LOS immunotypes (L2, L3, L4,
L5, L7, and L8) in Groups B and C bound specifically to Maackia amurensis
leukoagglutinin (MAL), which recognizes NeuNAcalpha2- 3Galbeta1-4GlcNAc/Glc
sequence, but not to Sambucus nigra agglutinin, which binds
NeuNAcalpha2-6Gal sequence. The combination of SDS-PAGE and MAL-blot
analyses revealed that these six LOSs contained only the
NeuNAcalpha2-3Galbeta1-4GlcNAc trisaccharide sequence in their 4.1 kDa LOS
components, which have a common terminal lacto-N-neotetraose (LNnT,
Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc) structure when nonsialylated as shown
by previous studies. The LOS-lectin binding was abolished when the LOSs
were treated with Newcastle disease viral neuraminidase which cleaves
alpha2-->3 linked sialic acid. Methylation analysis of a representative
LOS (L2) confirmed that NeuNAc is 2-->3 linked to Gal. Thus, these LOSs
structurally mimic certain glycolipids, i.e., paragloboside (LNnT-ceramide)
and sialylparagloboside and some glycoproteins in having LNnT and
N-acetyllactosamine sequences, respectively, with or without alpha2-->3
linked NeuNAc. The molecular mimicry of the LOSs may play a role in the
pathogenesis of N.meningitidis by assisting the organism to evade host
immune defenses in man.
相似文献
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10.
We investigated the role of the main olfactory and accessory olfactory systems (MOS and AOS respectively) in the detection of androstenone. We used the following experimental approaches: behavioral, surgical removal of the vomeronasal organ (VNX) followed by histochemical verification and Fos immunohistochemistry. Using a Y-maze paradigm we estimated sensitivity of NZB/B1NJ and CBA/J mice to androstenone. CBA mice were 2,000-fold more sensitive to androstenone than NZB mice. VNX caused a 4- to 16-fold decre... 相似文献