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21.
On the isolation of TI-plasmid from Agrobacterium tumefaciens. 总被引:3,自引:0,他引:3
A M Ledeboer A J Krol J J Dons F Spier R A Schilperoort I Zaenen N van Larebeke J Schell 《Nucleic acids research》1976,3(2):449-463
An efficient lysis method for Agrobacterium cells was developed, which allows a reproducible isolation of the tumor inducing (TI)-plasmid. The lysis method is based on the sensitivity of this bacterium to incubation with lysozyme, n-dodecylamine,EDTA, followed by Sarkosyl, after growth in the presence of carbenicillin. We also present a procedure for the isolation of the TI-plasmid on a large scale, that might be used for the mass isolation of other large plasmids which like the TI-plasmid, can not be cleared with earlier described procedures. The purity of the plasmid preparations was determined with DNA renaturation kinetics, which method has the advantage that the plasmid need not to be in the supercoiled or open circular form. 相似文献
22.
Book reviewed in this article:
EUROPE AND ASIA: Naskal'nye izobrazheniia Onezhskogo i Belgo moria: Les Gravures Rupestres des Bords du lac Onega et de la mer Blanche. V. I. R audonikas .
EUROPE AND ASIA: Première Partie:
EUROPE AND ASIA: Seconde Partie: 相似文献
EUROPE AND ASIA: Naskal'nye izobrazheniia Onezhskogo i Belgo moria: Les Gravures Rupestres des Bords du lac Onega et de la mer Blanche. V. I. R audonikas .
EUROPE AND ASIA: Première Partie:
EUROPE AND ASIA: Seconde Partie: 相似文献
23.
John A Babraj Niels BJ Vollaard Cameron Keast Fergus M Guppy Greg Cottrell James A Timmons 《BMC endocrine disorders》2009,9(1):1-8
Background
Impaired glucose tolerance (IGT) is a prediabetic state. If IGT can be prevented from progressing to overt diabetes, hyperglycemia-related complications can be avoided. The purpose of the present study was to examine whether pioglitazone (ACTOS®) can prevent progression of IGT to type 2 diabetes mellitus (T2DM) in a prospective randomized, double blind, placebo controlled trial.Methods/Design
602 IGT subjects were identified with OGTT (2-hour plasma glucose = 140–199 mg/dl). In addition, IGT subjects were required to have FPG = 95–125 mg/dl and at least one other high risk characteristic. Prior to randomization all subjects had measurement of ankle-arm blood pressure, systolic/diastolic blood pressure, HbA1C, lipid profile and a subset had frequently sampled intravenous glucose tolerance test (FSIVGTT), DEXA, and ultrasound determination of carotid intima-media thickness (IMT). Following this, subjects were randomized to receive pioglitazone (45 mg/day) or placebo, and returned every 2–3 months for FPG determination and annually for OGTT. Repeat carotid IMT measurement was performed at 18 months and study end. Recruitment took place over 24 months, and subjects were followed for an additional 24 months. At study end (48 months) or at time of diagnosis of diabetes the OGTT, FSIVGTT, DEXA, carotid IMT, and all other measurements were repeated. Primary endpoint is conversion of IGT to T2DM based upon FPG ≥ 126 or 2-hour PG ≥ 200 mg/dl. Secondary endpoints include whether pioglitazone can: (i) improve glycemic control (ii) enhance insulin sensitivity, (iii) augment beta cell function, (iv) improve risk factors for cardiovascular disease, (v) cause regression/slow progression of carotid IMT, (vi) revert newly diagnosed diabetes to normal glucose tolerance.Conclusion
ACT NOW is designed to determine if pioglitazone can prevent/delay progression to diabetes in high risk IGT subjects, and to define the mechanisms (improved insulin sensitivity and/or enhanced beta cell function) via which pioglitazone exerts its beneficial effect on glucose metabolism to prevent/delay onset of T2DM.Trial Registration
clinical trials.gov identifier: NCT00220961 相似文献24.
Mercator: a fast and simple web server for genome scale functional annotation of plant sequence data
MARC LOHSE AXEL NAGEL THOMAS HERTER PATRICK MAY MICHAEL SCHRODA RITA ZRENNER TAKAYUKI TOHGE ALISDAIR R. FERNIE MARK STITT BJÖRN USADEL 《Plant, cell & environment》2014,37(5):1250-1258
Next‐generation technologies generate an overwhelming amount of gene sequence data. Efficient annotation tools are required to make these data amenable to functional genomics analyses. The Mercator pipeline automatically assigns functional terms to protein or nucleotide sequences. It uses the MapMan ‘BIN’ ontology, which is tailored for functional annotation of plant ‘omics’ data. The classification procedure performs parallel sequence searches against reference databases, compiles the results and computes the most likely MapMan BINs for each query. In the current version, the pipeline relies on manually curated reference classifications originating from the three reference organisms (Arabidopsis, Chlamydomonas, rice), various other plant species that have a reviewed SwissProt annotation, and more than 2000 protein domain and family profiles at InterPro, CDD and KOG. Functional annotations predicted by Mercator achieve accuracies above 90% when benchmarked against manual annotation. In addition to mapping files for direct use in the visualization software MapMan, Mercator provides graphical overview charts, detailed annotation information in a convenient web browser interface and a MapMan‐to‐GO translation table to export results as GO terms. Mercator is available free of charge via http://mapman.gabipd.org/web/guest/app/Mercator . 相似文献
25.
26.
BJÖRN ROGELL MARTIN EKLUND HANNA THÖRNGREN ANSSI LAURILA JACOB HÖGLUND 《Molecular ecology》2010,19(11):2229-2240
Although loss of genetic variation is frequently assumed to be associated with loss of adaptive potential, only few studies have examined adaptation in populations with little genetic variation. On the Swedish west coast, the northern fringe populations of the natterjack toad Bufo calamita inhabit an atypical habitat consisting of offshore rock islands. There are strong among‐population differences in the amount of neutral genetic variation, making this system suitable for studies on mechanisms of trait divergence along a gradient of within‐population genetic variation. In this study, we examined the mechanisms of population divergence using QST–FST comparisons and correlations between quantitative and neutral genetic variation. Our results suggest drift or weak stabilizing selection across the six populations included in this study, as indicated by low QST–FST values, lack of significant population × temperature interactions and lack of significant differences among the islands in breeding pond size. The six populations included in this study differed in both neutral and quantitative genetic variation. Also, the correlations between neutral and quantitative genetic variation tended to be positive, however, the relatively small number of populations prevents any strong conclusions based on these correlations. Contrary to the majority of QST–FST comparisons, our results suggest drift or weak stabilizing selection across the examined populations. Furthermore, the low heritability of fitness‐related traits may limit evolutionary responses in some of the populations. 相似文献
27.
ANDREAS LUEK GEORGE E. MORGAN BJÖRN WISSEL JOHN M. GUNN CHARLES W. RAMCHARAN 《Freshwater Biology》2010,55(8):1616-1627
1. Yellow perch (Perca flavescens) are often the only surviving fish species in acidified lakes. We studied four lakes along a gradient of recovery from acidification and that had different food web complexities. All had abundant yellow perch, two had low piscivore abundance, one had a well‐established piscivore population and one was manipulated by introducing piscivorous smallmouth bass (Micropterus dolomieu). We hypothesised that there would be strong effects on perch abundance, behaviour and diet induced by the presence of piscivores. 2. In the manipulated lake, the bass reduced yellow perch abundance by 75% over a 2‐year period. Concomitantly, perch use of the pelagic habitat fell from 48 to 40%. 3. In contrast to findings from less disturbed systems, yellow perch in the littoral zone of the manipulated lake did not strongly shift from zooplankton to benthic food sources after the arrival of piscivores. Diet analysis using stable carbon isotopes revealed a strong continued reliance on zooplankton in all lakes, independent of the degree of piscivory. The failure to switch to benthos in the refuge area of the littoral zone is most likely related to the depauperate benthos communities in these formerly acidified lakes. 4. Yellow perch in lakes recovering from acidification face a considerable ecological challenge as the necessary switch to benthic diet is hindered by a low abundance of benthos. The arrival of piscivores in these recovering lakes imposes further restrictions on perch access to food items. We infer that future recovery of perch populations (and higher trophic levels) will have to be preceded by the re‐establishment of diverse benthic macroinvertebrate communities in these lakes. 相似文献
28.
29.
Abstract: The two odontocete taxa Squalodon grateloupii and Patriocetus ehrlichii, both the type species of their respective genera, have been at the centre of a great deal of taxonomic confusion. Originally regarded to be conspecific, these two taxa have been the subject of a bewildering taxonomic debate lasting for more than a century, which recently led to the suggestion to abandon these widely used names and replace S. grateloupii with the similar, yet independently and later proposed name S. gratelupi as the type species of Squalodon. Here, we attempt to summarise the events leading to the current confused situation in the hope of resolving this issue once and for all and argue that the name Squalodon grateloupii, as originally proposed, should be reinstated. 相似文献
30.
Spier RE 《Cytotechnology》1992,8(2):89-92
Pick up any textbook with ‘Microbiology’ in the title and observe the scant to nonexistent treatment of animal cells in culture. Viruses do not suffer from such an exclusion. Chapters abound regaling the molecular niceties of the complex dances their components undergo while infecting bacteria or animal cells in culture. Indeed, it is normally in the latter sense only that any recognition is given to the existence of animal cells in culture. Such views pervade even the minds of those who initiate and direct activities of societies whoseraison d’être is the growth and exploitation of animal cells in culture. The author of this editorial was appointed to a Chair in Microbiology at the University of Surrey in 1983 and has worked on the growth and use of animal cells in culture continuously since 1970; he, therefore, had to reconcile his position in the university with his chosen calling. In this he was helped by undergraduates too numerous to mention who struggled mightily with essays which asked the question; are animal cells in culture microorganisms? What follows is a digest of their efforts and the views of the author. 相似文献