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排序方式: 共有297条查询结果,搜索用时 15 毫秒
1.
Microsatellite DNA in peach (Prunus persica L. Batsch) and its use in fingerprinting and testing the genetic origin of cultivars. 总被引:11,自引:0,他引:11
R Testolin T Marrazzo G Cipriani R Quarta I Verde M T Dettori M Pancaldi S Sansavini 《Génome》2000,43(3):512-520
We isolated and sequenced 26 microsatellites from two genomic libraries of peach cultivar 'Redhaven', enriched for AC/GT and AG/CT repeats, respectively. For 17 of these microsatellites, it was possible to demonstrate Mendelian inheritance. Microsatellite polymorphism was assayed in 50 peach and nectarine cultivars. Of the 1300 PCRs carried out, all but two produced amplified products of the expected size. All microsatellites were polymorphic, showing 2-8 alleles per locus. Heterozygosity ranged from 0.04-0.74 (mean 0.47); the discrimination power (PD) ranged from 0.04-0.84 (mean 0.60). Cultivar heterozygosity varied greatly, with one cultivar ('Independence') being homozygous at all loci. The set of microsatellites discriminated all cultivars investigated, except several sport mutations, i.e., 'Dixitime' vs. 'Springcrest', 'Compact Redhaven' vs. 'Redhaven', and two pairs of cultivars, 'Venus' vs. 'Orion' and 'Elegant Lady' vs. 'Rome Star', whose pedigrees are controversial. We were able to analyze the paternity of several cultivars. In most cases, the parenthood was confirmed. The comparison of three long-living 'Redhaven' accessions supplied by different repositories did not provide any evidence of somatic instability of microsatellites. Hence, microsatellites, ranked according to their information content, are recommended as markers of choice for peach fingerprinting and suggestions are provided for interpreting band profiles and the correct sizing of alleles. 相似文献
2.
Production planning in flexible manufacturing may require the solution of a large-scale discrete-event dynamic stochastic optimization problem, due to the complexity of the system to be optimized, and to the occurrence of discrete events (new orders and hard failures). The production planning problem is here approached for a multistage multipart-type manufacturing shop, where each work cell can share its processing time among the different types of parts. The solution of this problem is obtained by an open-loop-feedback control strategy, updated each time a new event occurs. At each event time, two coupled problems are solved: 1) a product-order scheduling problem, conditioned on estimated values of the production capacities of all component work cells; and 2) a production-capacity planning problem, conditioned on predefined sequences of the product orders to be processed. In particular, the article aims at defining a production planning procedure that integrates both analytical tools, derived from mathematical programming, and knowledge-based rules, coming from experience. The objective is to formulate a hybrid (knowledge-based/analytical) planning architecture, and to analyze its use for multicell multipart-type manufacturing systems. 相似文献
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In C4 grasses belonging to the NADP-malic enzyme-type subgroup, malate is considered to be the predominant C4 acid metabolized during C4 photosynthesis, and the bundle sheath cell chloroplasts contain very little photosystem-II (PSII) activity. The present studies showed that Flaveria bidentis (L.), an NADP-malic enzyme-type C4 dicotyledon, had substantial PSII activity in bundle sheath cells and that malate and aspartate apparently contributed about equally to the transfer of CO2 to bundle sheath cells. Preparations of bundle sheath cells and chloroplasts isolated from these cells evolved O2 at rates between 1.5 and 2 mol · min–1 · mg–1 chlorophyll (Chl) in the light in response to adding either 3-phosphoglycerate plus HCO
3
–
or aspartate plus 2-oxoglutarate. Rates of more than 2 mol O2 · min–1 · mg–1 Chl were recorded for cells provided with both sets of these substrates. With bundle sheath cell preparations the maximum rates of light-dependent CO2 fixation and malate decarboxylation to pyruvate recorded were about 1.7 mol · min–1 · mg–1 Chl. Compared with NADP-malic enzyme-type grass species, F. bidentis bundle sheath cells contained much higher activities of NADP-malate dehydrogenase and of aspartate and alanine aminotransferases. Time-course and pulse-chase studies following the kinetics of radiolabelling of the C-4 carboxyl of C4 acids from 14CO2 indicated that the photosynthetically active pool of malate was about twice the size of the aspartate pool. However, there was strong evidence for a rapid flux of carbon through both these pools. Possible routes of aspartate metabolism and the relationship between this metabolism and PSII activity in bundle sheath cells are considered.Abbreviations DHAP
dihydroxyacetone phosphate
- NADP-ME(-type)
NADP-malic enzyme (type)
- NADP-MDH
NADP-malate dehydrogenase
- OAA
oxaloacetic acid
- 2-OG
2-oxoglutarate
- PEP
phosphoenolpyruvate
- PGA
3-phosphoglycerate
- Pi
orthophosphate
- Ru5P
ribulose 5-phosphate 相似文献
4.
Measurement of the Leakage of CO2 from Bundle-Sheath Cells of Leaves during C4 Photosynthesis 总被引:2,自引:2,他引:0
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During C4 photosynthesis, CO2 is released in bundle-sheath cells by decarboxylation of C4 acids and then refixed via ribulose-1,5-bisphosphate carboxylase. In this study we examined the efficiency of this process by determining the proportion of the released CO2 that diffuses back to mesophyll cells instead of being refixed. This leak of CO2 was assessed by determining the amount of 14CO2 released from leaves during a chase in high [12CO2] following a 70-s pulse in 14CO2. A computer-based analysis of the time-course curve for 14CO2 release indicated a first-order process and provided an estimate of the initial velocity of 14CO2 release from leaves. From this value and the net rate of photosynthesis determined from the 14CO2 fixed in the pulse, the CO2 leak rate from bundle-sheath cells (expressed as a percentage of the rate of CO2 production from C4 acids) could be deduced. For nine species of Gramineae representing the different subgroups of C4 plants and two NAD-malic enzyme-type dicotyledonous species, the CO2 leak ranged between 8 and 14%. However, very high CO2 leak rates (averaging about 27%) were recorded for two NADP-malic enzyme-type dicotyledonous species of Flaveria. The results are discussed in terms of the efficiency of C4 photosynthesis and observed quantum yields. 相似文献
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Sujatha Srinivasan Martin T. Morgan Congzhou Liu Frederick A. Matsen Noah G. Hoffman Tina L. Fiedler Kathy J. Agnew Jeanne M. Marrazzo David N. Fredricks 《PloS one》2013,8(10)
Bacterial vaginosis (BV) is a highly prevalent condition associated with adverse health outcomes. Gram stain analysis of vaginal fluid is the standard for confirming the diagnosis of BV, wherein abundances of key bacterial morphotypes are assessed. These Lactobacillus, Gardnerella, Bacteroides, and Mobiluncus morphotypes were originally linked to particular bacterial species through cultivation studies, but no studies have systematically investigated associations between uncultivated bacteria detected by molecular methods and Gram stain findings. In this study, 16S-rRNA PCR/pyrosequencing was used to examine associations between vaginal bacteria and bacterial morphotypes in 220 women with and without BV. Species-specific quantitative PCR (qPCR) and fluorescence in Situ hybridization (FISH) methods were used to document concentrations of two bacteria with curved rod morphologies: Mobiluncus and the fastidious BV-associated bacterium-1 (BVAB1). Rank abundance of vaginal bacteria in samples with evidence of curved gram-negative rods showed that BVAB1 was dominant (26.1%), while Mobiluncus was rare (0.2% of sequence reads). BVAB1 sequence reads were associated with Mobiluncus morphotypes (p<0.001). Among women with curved rods, mean concentration of BVAB1 DNA was 2 log units greater than Mobiluncus (p<0.001) using species-specific quantitative PCR. FISH analyses revealed that mean number of BVAB1 cells was 2 log units greater than Mobiluncus cells in women with highest Nugent score (p<0.001). Prevotella and Porphyromonas spp. were significantly associated with the “Bacteroides morphotype,” whereas Bacteroides species were rare. Gram-negative rods designated Mobiluncus morphotypes on Gram stain are more likely BVAB1. These findings provide a clearer picture of the bacteria associated with morphotypes on vaginal Gram stain. 相似文献
10.
Alessandro Romano Agostino Sorgonà Antonio Lupini Fabrizio Araniti Piergiorgio Stevanato Giovanni Cacco Maria Rosa Abenavoli 《Acta Physiologiae Plantarum》2013,35(3):853-865
The identification of morpho-physiological traits related to drought tolerance and high yield potential is a challenge when selecting sugar beet genotypes with greater tolerance to water stress. In this paper, root morphological parameters, antioxidant systems, leaf relative water content (RWC) and H+-ATPase activity as key morpho-physiological traits involved in drought tolerance/susceptibility of sugar beet were studied. Genotypes showing a different drought tolerance index (DTI) but a similar yield potential, under moderate (?0.6 Mpa) and severe (?1.2 MPa) water stress, were selected and their morpho-physiological traits were investigated. The results showed a wide genetic variation in morpho-physiological parameters which demonstrated the different adaptive strategies under moderate and severe drought conditions in sugar beet. In particular, an efficient antioxidant system and redox signalling made some sugar beet genotypes more tolerant to drought stress. The alternative strategy of other genotypes was the reduction of root tissue density, which produced a less dense root system improving the axial hydraulic conductivity. These results could be considered as interesting challenge for a better understanding of the drought tolerance mechanisms in sugar beet. 相似文献