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11.
Sonication: A new method for gene transfer to plants 总被引:9,自引:0,他引:9
Sonication is a novel method for gene transfer into plant protoplasts and intact plant cells. The mode of action of ultrasound and its chemical, biochemical and physiological effects are reviewed. The state of the art of acoustic transformation is presented and possible mechanisms are discussed. 相似文献
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14C-labeled extracellular organic carbon (EOC) released by the phytoplankton in a Danish Estuary was shown immediately to form particles (>0.2m) when the products were added to a natural water sample. About 14%–20% of the added activity could be recovered as particles. Any bacterial assimilation of the extracellular products was thus masked. The abiotic origin of the particulate EOC was verified, and it was shown that the particle formation was due to some factors present in the estuarine water with a nominal diameter >0.2m. Precaution must be taken to avoid misinterpretations in studies concerning carbon flow from algae to bacteria. 相似文献
14.
Involvement of the cytoplasmic membrane in nitrogen fixation by Rhizobium leguminosarum bacteroids 总被引:6,自引:0,他引:6
1. The nitrogen-fixing efficiency of freshly prepared suspensions of Rhizobium leguminosarum bacteroids from pea root nodules was considerably enhanced by addition of bovine serum albumin. Evidence was found that during preparation of bacteroids the cell membrane is exposed to the uncoupling effect of free fatty acids and to plant phospholipase D activity. Both effects could be counteracted by bovine serum albumin. 2. A technique was developed by which concentrations of free O2 and nitrogenase activity could be measured simultaneously under conditions of steady-state respiration. By means of this system it could be shown that in contrast to previous claims, high ATP/ADP ratios can be achieved in bacteroids even with a high concentration of O2 in the medium. 3. Nitrogen fixation was found to be controlled by the ATP/ADP ratio, the generation of reducing equivalents and the switch-off phenomenon. It was demonstrated that the generation of reducing equivalents for nitrogenase is regulated by the energized state and the integrity of the bacteroid cell membrane. The data indicate that the process of aerobic nitrogen fixation in R. leguminosarum bacteroids resembles that of Azotobacter vinelandii. 相似文献
15.
The human aldose reductase gene maps to chromosome region 7q35 总被引:1,自引:0,他引:1
Alexander Graham Paul Heath John E. N. Morten Alexander F. Markham 《Human genetics》1991,86(5):509-514
Summary The human aldose reductase (AR) gene has been mapped to chromosome 7 using the polymerase chain reaction to specifically amplify the human AR sequence in hamster/human hybrid DNA and also in mouse/ human monochromosome hybrids. The assignment to chromosome 7 was confirmed by in situ hybridisation to human metaphase chromosomes using a novel, rapid hybridisation, method giving a regional localisation at 7q35. 相似文献
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Jonny Beyer Morten Sandvik Janneche U. Skare Eliann Egaas Ketil Hylland Rune Waagbo 《Biomarkers》2013,18(1):35-44
Responses in flounder (Platichthys flesus) towards benzo [a]pyrene (BaP), 2,3,3′,4,4′,5-hexachlorobiphenyl (PCB-156), and cadmium (Cd) were investigated in time-course and dose-response studies of selected biomarkers. Measurements of biliary fluorescent BaP metabolites and hepatic concentrations of PCB-156 and cadmium showed that the injected toxicants were rapidly m obilized from the muscle to the liver, but a depot effect was indicated in the highest dose groups of BaP and PCB-156 (12 mg kg-1 bodyweight). Clearest biomarker responses were found in the induction of hepatic cytochrome P450 1A (CYP1A) enzymes as a response towards BaP and PCB-156 exposure. Maximum induction of CYP1A dependent 7-ethoxyresorufin O-deethylase (EROD) activity was observed after 2 and 8 days in BaP and PCB-156-treated flounder, respectively. Positive dose-effect relationships were observed towards both compounds, but the CYP1A induction was more persistent with PCB exposure than with BaP exposure. In Cd-exposed fish, the hepatic level of metallothionein responded more slowly with highest levels observed after 16 days in the time-study. In the combined BaP + Cd treatment, the CYP1A induction was only slightly suppressed. Aspartate aminotransferase in serum appeared to be responsive towards BaP, but also towards the acetone vehicle in controls in the first part of the exposure period. Hematocrit as well as hepatic activities of aldrin epoxidase, glutathione S-transferase, and UDP-glucuronyl transferase were not responsive to any treatm ent in the present study. In general, the results demonstrate that selected biom arkers in flounder are responsive to PAH, PCB, and heavy metal pollutant exposure, indicating the applicability of this species in future environmental pollution monitoring programmes. 相似文献
18.
Frederik Banch Clausen Tanja Roien Jakobsen Klaus Rieneck Grethe Risum Krog Leif Kofoed Nielsen Ann Tabor Morten Hanefeld Dziegiel 《PloS one》2013,8(10)
Background
Non-invasive prenatal testing of cell-free fetal DNA (cffDNA) in maternal plasma can predict the fetal RhD type in D negative pregnant women. In Denmark, routine antenatal screening for the fetal RhD gene (RHD) directs the administration of antenatal anti-D prophylaxis only to women who carry an RhD positive fetus. Prophylaxis reduces the risk of immunization that may lead to hemolytic disease of the fetus and the newborn. The reliability of predicting the fetal RhD type depends on pre-analytical factors and assay sensitivity. We evaluated the testing setup in the Capital Region of Denmark, based on data from routine antenatal RHD screening.Methods
Blood samples were drawn at gestational age 25 weeks. DNA extracted from 1 mL of plasma was analyzed for fetal RHD using a duplex method for exon 7/10. We investigated the effect of blood sample transportation time (n = 110) and ambient outdoor temperatures (n = 1539) on the levels of cffDNA and total DNA. We compared two different quantification methods, the delta Ct method and a universal standard curve. PCR pipetting was compared on two systems (n = 104).Results
The cffDNA level was unaffected by blood sample transportation for up to 9 days and by ambient outdoor temperatures ranging from -10°C to 28°C during transport. The universal standard curve was applicable for cffDNA quantification. Identical levels of cffDNA were observed using the two automated PCR pipetting systems. We detected a mean of 100 fetal DNA copies/mL at a median gestational age of 25 weeks (range 10–39, n = 1317).Conclusion
The setup for real-time PCR-based, non-invasive prenatal testing of cffDNA in the Capital Region of Denmark is very robust. Our findings regarding the transportation of blood samples demonstrate the high stability of cffDNA. The applicability of a universal standard curve facilitates easy cffDNA quantification. 相似文献19.
Diana J. Leeming Morten A. Karsdal Lars M. Rasmussen Alexandra Scholze Martin Tepel 《PloS one》2013,8(8)
Objective
The 7S domain of collagen type IV (P4NP_7S) assessed in plasma represents systemic collagen type IV formation. The objective of the study was to investigate the association of systemic collagen type IV formation with survival among patients undergoing hemodialysis.Methods
We performed an observational cohort study of 371 hemodialysis patients. Plasma P4NP_7S was analyzed using a specific enzyme-linked immunosorbent assay detecting the amino-terminal propeptide of type IV procollagen. Association between categories of plasma P4NP_7S concentrations and survival was initially assessed by Kaplan-Meier analysis, then in an adjusted Cox model.Results
For hemodialysis patients in the highest category of systemic collagen type IV formation, i.e. plasma P4NP_7S concentrations more than 775 pg/L, an increased risk for death was observed (highest P4NP_7S category vs all other categories, hazard ratio, 1.934; 95% confidence interval, 1.139 to 3.285). Survival analysis showed an increased risk of death in the highest P4NP_7S category compared to the other categories (Chi square 6.903; P = 0.032). Median survival was only 105 days in the highest P4NP_7S category whereas it was 629 days in the medium category, and 905 days in the lowest category. Multivariable-adjusted Cox regression showed increased odds for death with higher age and higher P4NP_7S categories. Systemic collagen type IV formation was associated with plasma concentrations of the collagen IV degradation product C4M (Spearman r = 0.764; P<0.0001) confirming extracellular matrix turnover.Conclusion
Among hemodialysis patients elevated systemic collagen type IV formation suggesting accelerating systemic fibrosis was associated with increased risk of death. 相似文献20.
Caio Cesar de Souza Alves Adam Collison Luke Hatchwell Maximilian Plank Matthew Morten Paul S. Foster Sebastian L. Johnston Cristiane Fran?a da Costa Mauro Vieira de Almeida Henrique Couto Teixeira Ana Paula Ferreira Joerg Mattes 《PloS one》2013,8(11)