Search Results - (Author, Cooperation:D. Bartels)
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1Latest Papers from Table of Contents or Articles in PressR. VanBuren ; D. Bryant ; P. P. Edger ; H. Tang ; D. Burgess ; D. Challabathula ; K. Spittle ; R. Hall ; J. Gu ; E. Lyons ; M. Freeling ; D. Bartels ; B. Ten Hallers ; A. Hastie ; T. P. Michael ; T. C. Mockler
Nature Publishing Group (NPG)
Published 2015Staff ViewPublication Date: 2015-11-13Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Acclimatization/genetics ; Contig Mapping ; Dehydration ; Desiccation ; Droughts ; Genes, Plant/genetics ; Genome, Plant/*genetics ; Genomics ; Molecular Sequence Data ; Poaceae/*genetics ; Sequence Analysis, DNA/*methodsPublished by: -
2Articles: DFG German National LicensesBartels, D. M. ; Lawler, R. G.
College Park, Md. : American Institute of Physics (AIP)
Published 1987Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: The radical ion ⋅SO−3 was studied by in situ pulsed radiolysis of aqueous alkaline sodium sulfite solutions in a pulsed EPR spectrometer. Initial radical concentrations on the order of 5×10−4 M were generated, and detailed measurements of the decay of ⋅SO−3 magnetization were performed on the microsecond time scale. It was found that the second order decay of both longitudinal and transverse magnetization lags behind the second order decay of radical population when the reaction rate approaches the relaxation rates 1/T1,2. The observations may be explained in terms of the spin-pairing requirements for formation of a singlet reaction product. The spin pairing gives rise to a "passive'' form of radical pair mechanism (RPM) chemically induced dynamic electron polarization (CIDEP) which has previously gone unrecognized. RPM polarization therefore occurs in ⋅SO−3 encounters despite the lack of hyperfine dependent singlet–triplet mixing between radical reencounters, which is necessary for the accepted RPM mechanism. The implications of these observations for the interpretation of time-resolved EPR experiments are discussed.Type of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesBartels, D. M. ; Lawler, R. G. ; Trifunac, A. D.
College Park, Md. : American Institute of Physics (AIP)
Published 1985Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: A dynamic polarization recovery method for measurement of electron spin T1 relaxation times in free radicals in liquids is described, which is valid even in the presence of chemically induced dynamic electron polarization (CIDEP) and fast chemical decay of the radicals. The method is based on pulsed microwave perturbation and detection of transient magnetization following radical creation in a short pulse. Analysis of the experimental approach and a theoretical description of the method is presented together with a detailed discussion of the advantages and the limitations of the technique. Electron T1 measurements are presented for 14 short-lived free radicals generated in aqueous solution. The magnitudes of the observed relaxation times, which range from 0.1 to 4 μs, are discussed within the framework of current theories of relaxation for small radicals in liquids. It is tentatively concluded that the spin rotation mechanism is responsible for the very short T1's in this series of radicals.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesSMITH-ESPINOZA, C. J. ; RICHTER, A. ; SALAMINI, F. ; BARTELS, D.
Oxford, UK : Blackwell Science Ltd
Published 2003Staff ViewISSN: 1365-3040Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyNotes: Although desiccation tolerant, the resurrection plant Craterostigma plantagineum is sensitive to relatively low levels of sodium chloride. Exposure to sodium chloride, but not dehydration, led to accumulation of sodium ions in leaves and roots and caused irreversible wilting. The effects of salt and dehydration on transcript accumulation patterns were studied by using selected cDNA clones that were related to water stress. Most of the clones represented genes that were up-regulated in response to both treatments. Among the transcripts specifically up-regulated by dehydration were RNAs encoding transcripts with homology to aquaporins. Expression analysis revealed dehydration-specific profiles of late embryogenesis abundant (LEA) genes, which differed from the patterns observed for the same genes under sodium chloride stress. The interconversion of octulose and sucrose, which is characteristic for the desiccation/rehydration cycle in C. plantagineum leaves, was not activated by sodium chloride. The present results suggest that dehydration-specific responses involve the synchronized expression of specific genes and the presence of a determined concentration of sucrose. These dehydration responses were not detected in response to sodium chloride treatment.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 1365-3040Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyNotes: Plant productivity is greatly affected by environmental stress factors. In this review, we give an overview of molecular approaches that have been taken to study stress tolerance; in particular, we consider drought, salt and cold stress. Strategies and perspectives in using molecular biology to improve stress tolerance are outlined describing specific examples. Osmotic stress is associated with the synthesis of novel polypeptides and/or osmolytes. The spectrum and action of these different metabolites are summarized. A number of stress-related genes have been characterized and several representatives are discussed. After transforming plants with these genes, the effect of the encoded proteins on altered stress behaviour is examined. If genes with enzymatic functions were chosen for these experiments, complete pathways may be altered and this can implement the production of novel metabolites conferring stress tolerance.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesStaff View
ISSN: 1365-3040Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyNotes: Desiccation is the extreme form of dehydration. Tolerance of desiccation is acquired by seeds and in resurrection plants, a small group of angiosperms. Desiccation tolerance is the result of a complex cascade of molecular events, which can be divided into signal perception, signal transduction, gene activation and biochemical alterations leading to acquisition of tolerance. Many of these molecular processes are also observed during the dehydration of non-tolerant plants. Here we try to give an overview of the gene expression programmes that are triggered by dehydration, with particular reference to protective molecules and the regulation of their expression. Potential transgenic approaches to manipulating stress tolerance are discussed.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesStaff View
ISSN: 1365-3040Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: BiologyNotes: Craterostigma plantagineum is a representative of the resurrection plants, which are able to withstand complete dryness. During the dehydration process, many characteristic transcripts and proteins are induced; these have been isolated by molecular cloning. The expression of most of these gene products can also be triggered by ABA. Five representative desiccation-related cDNA clones were selected. The effect of light and developmental stage on the expression of the transcripts and corresponding proteins was analysed during dehydration and ABA treatment. Desiccation and ABA treatment in the presence of light induced a marked increase in several of the transcripts, whereas light had the reverse effect on the levels of some proteins (relative to mRNA levels) localized in the chloroplast. Although very young plants have the capacity to resume full physiological activity after dehydration, some of the desiccation-related gene products are still expressed at low levels.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesStaff View
ISSN: 0378-1119Keywords: Recombinant DNA ; fusion protein ; glutenin ; lac promoter ; plasmid ; viscoelastic properties of doughSource: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: BiologyType of Medium: Electronic ResourceURL: -
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