Cloning and Sequence Analysis of Lipoxygenase Gene cDNA from Cucumber Fruit （Cucumis sativus L.）     

Lipoxygenases are nonheme-iron-containing dioxygenases that catalyze the hydroperoxidation of unsatrated fatty acids containing a cis  cis-  -pentadiene structure producing hydroperoxy acids with conjugated dienes.…… 《分子植物育种》2007,5(2):188-189

Lipoxygenases are nonheme-iron-containing dioxygenases that catalyze the hydroperoxidation of unsatrated fatty acids containing a cis, cis-1,4-pentadiene structure producing hydroperoxy acids with conjugated dienes. LOX activity has been found in a wide range of plants. Typical substrates for LOX in plants are linoleic acid and linilenic acid fatty acids. The function of various LOXs in plants is unknown, but their participation in all stages of plant growth and development has been suggested （Hildebrand, 1989; Siedow, 1991）. Some of the physiological processes in whicn lipoxygenses have been implicated include wounding （Saravitz and Siedow, 1996）, pathogen attack （Melan et al., 1993）, seed germination （Kato et al., 1992）, fruit ripening （Ferrie et al., 1994）, plant senescence （Paliyath and Droillard, 1992）. The study on the role of lipoxygenase in ripening and senescence fruit focused on tomato and strawberry. Cloning LOX gene of cucumber fruit will make us further understand the molecularaction mode of this enzyme during fxuit ripening and senescence. In this paper we isolated the partial nucleotide sequences of cucumber fiuit lipoxygenase gene and discuss the characterization of it.  相似文献   

A Simple and Reliable Assay for Detecting Specific Nucleotide Sequences in Plants Using Optical Thin-film Biosensor Chips     

Here we report the adaptation  optimization of an efficient  accurate  inexpensive assay that employs custom-designed silicon-based optical thin-film biosensor chips to detect unique transgenes in genetically modified 《分子植物育种》2007,5(2):241-241

Here we report the adaptation and optimization of an efficient, accurate and inexpensive assay that employs custom-designed silicon-based optical thin-film biosensor chips to detect unique transgenes in genetically modified （GM） crops and SN-P markers in model plant genomes. Briefly, aldehyde-attached sequence-specific singlestranded oligonucleotide probes are arrayed and covalently attached to a hydrazine-derivatized biosensor chip surface. Unique DNA sequences （or genes） are detected by hybridizing biotinylated PCR amplicons of the DNA sequences to probes on the chip surface. In the SN-P assay, target sequences （PCR amplicons） are hybridized in the presence of a mixture of biotinylated detector probes and a thermostable DNA ligase. Only perfect matches between the probe and target sequences, but not those with even a single nucleotide mismatch, can be covalently fixed on the chip surface. In both cases, the presence of specific target sequences is siL, nified by a color change on the chip surface （gold to blue/purple） after brief incubation with an anti-biotin IgG horseradish peroxidase （HRP） to generate a precipitable product from an HRP substrate.  相似文献   

Characterization of the intrarenal renin‐angiotensin system in cats with naturally occurring chronic kidney disease     

Bianca N. Loureno  Amanda E. Coleman  Roy D. Berghaus  Jaime L. Tarigo  Chad W. Schmiedt  Scott A. Brown 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2022,36(2):647

  相似文献   

Comparison between barbed and conventional sutures for longitudinal thelotomy closure in an ex-vivo bovine model     

Neshan W. Sarkisian  Pierre-Yves Mulon 《The Canadian veterinary journal. La revue veterinaire canadienne》2022,63(5):535

Objective To determine differences in suture time and bursting strength on a longitudinal thelotomy closure using innovative barbed versus conventional smooth suture materials.Sample population Twenty-four teats from 6 udders of culled beef cows.Study design Experimental ex-vivo surgical study.Methods Thelotomies (length: 2 cm) were performed on every teat and randomly allocated to closure with either a 3-0 bidirectional barbed suture for both mucosa and connective layers or a conventional 3-layer suture, using 3-0 smooth polydioxanone. For both groups, skin was closed with 2-0 polypropylene monofilament suture. Duration of suturing time for inner layers and bursting strength of the repair were recorded and compared.Results Suturing was faster with barbed versus conventional sutures (527.7 ± 64.5 versus 727.1 ± 60.7 s, respectively; P < 0.0001). However, bursting strength was not significantly different between the 2 types of sutures.Conclusion Using the barbed suture significantly reduced the time required to suture the mucosa and conjunctiva layers, with no significant difference between sutures in their bursting strength.Clinical significance Bidirectional barbed suture material is suitable for closure of thelotomies in cattle.  相似文献   

河套盐碱地不同利用方式土壤盐碱化特征差异分析   总被引：3，自引：0，他引：3  

景宇鹏  连海飞  李跃进  李秀萍  高娃  狄彩霞  栗燕芳  康文钦 《水土保持学报》2020,34(4):354-363

为研究河套平原盐碱地在不同利用方式对土壤盐碱化特征分布的影响,通过野外调查取样和室内分析相结合的方法,对5种土地利用方式下(林地、农用地、牧草地、改良地、盐荒地)不同深度土壤剖面形态特征、可溶盐含量、盐分离子组成、总碱度、pH、碱化度等指标的变化规律进行了系统研究。结果表明:不同利用方式土壤剖面土体结构、颜色、根系分布、石灰性反应及碱化层分布均有明显差异;土壤剖面的可溶性盐、阴阳离子分布因土地利用方式不同而存在差异,牧草地和林地土壤剖面可溶性盐呈"橄榄"型、盐荒地和改良地呈"表聚"型、农用地呈"底聚"型;土壤pH、碱化度和总碱度在剖面中的分布特征基本一致,呈"S"型;经不同利用方式土壤的盐化程度和碱化程度均有所下降,与盐荒地相比,农用地盐碱化指标下降的最为显著(P0.05),其中0—20 cm土壤全盐量降至0.88 g/kg,pH降至7.83,总碱度、ESP降至0.17 cmol/kg和12.54%,表明苏打盐碱地经农用后更有利于土壤脱盐化过程和脱碱化过程;土壤全盐量、Ca~(2+)、Mg~(2+)、SO_4~(2-)、总碱度、pH可作为控制区域盐碱化的主要因子。研究结果为阐明河套平原盐碱地的盐碱化过程及盐碱化土壤利用模式提供技术参考。  相似文献   

Physiological interpretation of a hyperspectral time series in a citrus orchard     

Jan StuckensSebinasi Dzikiti  Willem W. Verstraeten  Stephan Verreynne  Rony Swennen  Pol Coppin 《Agricultural and Forest Meteorology》2011,151(7):1002-1015

Hyperspectral remote sensing for monitoring horticultural production systems requires the understanding of how plant physiology, canopy structure, management and solar elevation affect the retrieved canopy reflectance during different stages of the phenological cycle. Hence, the objective of this study was to set up and to interpret a hyperspectral time series for a mature and healthy citrus orchard in the Western Cape province of South Africa considering these effects. Based on the remotely sensed data, biophysical parameters at the canopy level were derived and related to known observed physiological and phenological changes at the leaf level and to orchard management. Fractions of mature fruit, flowers, and sunburnt leaves were considered, and indices related to canopy structure chlorophyll content and canopy water status were calculated.Results revealed small cover fractions of mature fruit, flowers and sunburnt leaves of respectively 2.1%, 3.1% and 7.0%, but the high spectral contrast between flowers and leaves allowed a successful classification of flowering intensity. Furthermore, it was shown that canopy level time series of vegetation indices were sensitive to changes in solar elevation and soil reflectance which could be reduced by applying an empirical soil line correction for the most affected indices. Most trends in vegetation indices at the canopy level could be explained by a combination of changes at the leaf level (chlorophyll, carotenoids, dry matter), changes in canopy structure (leaf area index and leaf angle distribution) and changes in cover fractions of vegetative flushes, flowers and sunburnt leaves. The transformed chlorophyll absorption ratio index over the optimised soil adjusted vegetation index (MCARI/OSAVI) was best related to leaf level trends in chlorophyll content. Seasonal changes in the photochemical reflectance index (PRI) were linked to inverse changes in the carotenoid-to-chlorophyll ratio. Canopy structure indices (the modified triangular vegetation index or MTVI2 and the standardized leaf area index determining index or sLAIDI) were sensitive to changes in leaf area index, average leaf angle as well to management interactions (pruning and harvest). Canopy water status was highly impacted during the spring flush due to expanding leaves that concealed trends in the underlying mature leaves. Seasonal trends in soil and weeds reflectance were related to changes in volumetric soil water content and to the earlier and reduced growth period of non-irrigated weeds.  相似文献   

Seasonal variation in canopy reflectance and its application to determine the water status and water use by citrus trees in the Western Cape, South Africa     

Sebinasi Dzikiti  Stephan J. VerreynneJan Stuckens  Albert StreverWillem W. Verstraeten  Rony SwennenKaren I. Theron  Pol Coppin 《Agricultural and Forest Meteorology》2011,151(8):1035-1044

This study describes the diurnal and seasonal dynamics of the canopy reflectance, water use and water status of Midknight Valencia citrus trees under semi-arid conditions. Hyperspectral canopy reflectance data was collected on 30 trees at monthly intervals over a period of 16 months in a commercial orchard in South Africa. The mean canopy reflectance in the wavelength range 350-2500 nm followed a clear seasonal trend influenced by environmental conditions and tree phenology. Mean monthly reflectance peaked in summer (∼22%) while the lowest value (∼15%) was reached in winter with the seasonal changes in the sun's position accounting for a significant proportion of the variations. A sensitivity analysis of a Penman-Monteith transpiration model showed that water use by individual trees changed by up to 13% when the canopy reflectance was varied over the seasonal range of measured values. This suggested that the seasonal changes in tree water use influenced the seasonal trend of the canopy reflectance. Thus monitoring the canopy reflectance of citrus trees could offer information on the tree water status. To test this, sap flow data of water uptake and loss by the trees were compared with the canopy spectra. Sap flow data showed a heavy reliance by the citrus trees on the internally stored water with up to 25% of the daily total transpiration withdrawn from the trees’ internal water storage pools when soil water was limited. This depletion of internally stored water, and hence the change in tree water status, was detected using spectral indices based on the first order derivatives of the canopy reflectance centered at two and, at most, four spectral bands. We conclude that even if citrus trees are evergreen, their canopy reflectance changes significantly throughout the year with a considerable impact on tree energy balance and water use. In addition, the contribution of the internally stored water to daily transpiration is a possible indicator of drought stress for citrus trees detectable from changes in canopy reflectance and it has potential applications in irrigation scheduling using canopy level spectral information.  相似文献   

Chemical and sensory quantification of geosmin and 2-methylisoborneol in rainbow trout (Oncorhynchus mykiss) from recirculated aquacultures in relation to concentrations in basin water     

Petersen MA  Hyldig G  Strobel BW  Henriksen NH  Jørgensen NO 《Journal of agricultural and food chemistry》2011,59(23):12561-12568

Globally, aquaculture systems with water recirculation experience increasing problems with microbial taste and odor compounds (TOCs) such as geosmin and 2-methylisoborneol (MIB). This study investigated the content of geosmin and MIB in water and the flesh of 200 rainbow trouts from eight recirculated aquaculture systems in Denmark. TOC content in the fish flesh was measured by a dynamic headspace extraction method and was evaluated by a sensory panel. The results showed significant correlations between TOC content in water and fish and between chemical analysis and sensory perception. When geosmin exceeded 20 ng/L in the water, 96% of the fish had an intense muddy flavor, but below 10 ng geosmin/L, 18% of the fish (only 3% in special depuration ponds) had an intense muddy flavor. The results indicate that TOC levels <10 ng/L will ensure that a negligible portion of the fish obtains an unpalatable taste and flavor due to TOCs.  相似文献   

Insular pest control within a metapopulation context     

James C. Russell  Jamie W.B. Mackay  Jawad Abdelkrim 《Biological conservation》2009,142(7):1404-1410

Introduced pests threaten many species and their control is generally beneficial for conservation, particularly on islands where complete eradication is possible. Unfortunately on ‘nearshore’ islands neighbouring source populations exist and unaided reinvasion is likely. Pest control programmes at these sites thus require a metapopulation context to adequately manage movements between source and sink populations. We investigated the ecology of introduced ship rats (Rattus rattus) on a nearshore island, and gene flow with adjacent mainland populations, in order to understand the metapopulation dynamics and relative levels of pest control required within the landscape. We sampled the entire population by trapping (n = 30), achieving eradication, and found a low rat density (3.2 ha⁻¹) indicative of a sink population. Seed and other plant material constituted the major dietary component of rats. Despite its proximity to mainland source populations, the island population was genetically distinct with reduced allelic diversity caused by a recent reinvasion founder effect. Genetic analyses also detected recent migrants between the populations. In contrast, two mainland populations separated by a similar distance displayed complete genetic mixing. The small water gap therefore provides a sufficient barrier to lower the migration rate to the island and delay reinvasion, which nonetheless eventually happens. In order to maintain nearshore islands pest-free, conservation management will require a metapopulation approach simultaneously focusing on both island and source population pest control.  相似文献   

Growth and Metal Accumulation of Geyer and Mountain Willow Grown in Topsoil versus Amended Mine Tailings     

M. J. Boyter  J. E. Brummer  W. C. Leininger 《Water, air, and soil pollution》2009,198(1-4):17-29

Willows (Salix spp.) are an integral component in the restoration of wetland plant communities that have been impacted by the fluvial deposition of mine tailings. A greenhouse study was conducted to compare growth and metal uptake of Geyer (S. geyeriana) and mountain (S. monticola) willow grown in topsoil versus lime and biosolids amended mine tailings. Biomass, leader length, and tissue metal contents were measured after four months growth. Above and belowground biomass and leader length of Geyer willow were greater for plants grown in topsoil compared to amended mine tailings. However, soil type did not affect mountain willow growth. Analysis for five metals yielded complex results for the two willow species and soil types. As compared to mountain willow, Geyer had greater concentrations of Mn and Pb in aboveground tissues, and Cu in senesced leaves and bark-less leaders when grown in tailings; mountain willow leaves contained greater levels of Cd than Geyer when grown in tailings. Both willow species had foliar Cd levels which were above livestock toxicity tolerance values. Based on growth characteristics, mountain willow appeared better suited for restoration of mine tailings compared to Geyer willow. However, because of the high Cd uptake by both willow species, care should be taken in restoration efforts where wildlife and domestic livestock are likely to browse on the willows.  相似文献