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  • 1980-1984  (7)
  • 1950-1954
  • 1900-1904
  • Life and Medical Sciences  (3)
  • Chemical Engineering  (2)
  • Rhizobium  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Enhanced nodulation of leguminous plant roots by mixed cultures ofAzotobacter vinelandii and rhizobium (1981)
    Springer
    Plant and soil 62 (1981), S. 399-412 
    Details
    ISSN: 1573-5036
    Keywords: Azotobacter ; Glycine max ; Nodulation ; Rhizobium ; Trifolium repens ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Azotobacter vinelandii strains caused the formation of increased numbers of root nodules onGlycine max, Vigna unguiculata andTrifolium repens by their respective rhizobial symbionts. Increased nodulation due to inoculation withA. vinelandii also occurred in field grownG. max. Mutant strains ofA. vinelandii unable to fix nitrogen caused nodulation increases comparable to those caused by nitrogen-fixing strains. This indicates that nitrogen fixation byA. vinelandii was not responsible for the enhanced nodulation. The effect ofA. vinelandii on nodulation was greatest when cells from the mid-exponential phase of growth were applied as inoculants. Non viable cell preparations ofAzotobacter vinelandii were also found to cause an increase in the number of root nodules formed onGlycine max Rhizobium japonicum under greenhouse conditions. The nodulation enhancement activity was influenced by the method chosen to kill theA. vinelandii cells. Heat treatment and treatment with lethal levels of streptomycin destroyed the activity, whereas the activity was unaffected by ultraviolet-light treatment of the cells. Cell-free extracts ofA. vinelandii were found to enhance nodulation. On the other hand, culture supernatants ofA. vinelandii had no effect on nodulation. A split-root experiment suggested that the agent(s) responsible for the increased nodulation was not translocatable throughout the plant. The results suggest a non-excretable protein, produced byA. vinelandii, as a possible mechanism for nodulation enhancement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374137
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Isolation and partial characterization of Fix− mutants from Rhizobium strain 32H1 (1983)
    Springer
    Plant and soil 74 (1983), S. 395-406 
    Details
    ISSN: 1573-5036
    Keywords: Fix− mutants ; Fix+ revertants ; Macroptilium lathyroides ; Nitrogen fixation ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eight ineffective mutant strains were isolated from N-methyl-N'-nitro-N-nitrosoguanidine mutagenized cultures of cowpea Rhizobium strain 32H1. Strains CR1, CR2, CR3, CR4, CR5 and CR6 induced more, but smaller, nodules than the wild type. With the exception of strain CR2, these mutant strains reduced less than 1% of the amount of acetylene reduced by the wild type, in both the free-living and symbiotic assays. Strain CR2 reduced acetylene in the free-living assay but not in the symbiotic assay. Strains CR7 and CR8 responded variably (5–20% of the wild type) in free-living and symbiotic acetylene reduction assays. Nodules also varied from small white to normal-sized pink nodules. The phenotypic characteristics of the mutant strains were consistant with all leguminous plants tested and were stable upon reisolation from nodules. Fully effective revertants were selected from 4 of the ineffective mutant strains by the use of the leguminous plant,Macroptilium lathyroides. Serology, patterns of resistance to anti-bacterial agents, phage-typing, and antibiotic resistance markers were used to confirm strain identification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181357
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Hydrogen bonding potential, HBP: A model for predicting resin solubilities in organic solvents (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 810-815 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In a previous paper, a two-parameter model was described that could be used to predict the hydrogen bond enthalpy of formation between two compounds forming a single hydrogen bond. This paper describes the extension of the use of the two parameters for solvents and polymeric resins in another mathematical model that involves four terms that determine the “hydrogen bonding potential” (HBP) interaction between a resin and a given solvent. Each solvent and each resin can be assigned a donating and accepting parameter (relative to hydrogen bond formation) that combine to yield a numeric value for HBP. A negative HBP value is associated with favorable hydrogen bonding between a resin and a solvent which should correspond to a situation in which solution formation is favorable. A positive HBP value indicates unfavorable interaction which discourages solution formation. Thus, HBP becomes a predictive model of solubilities. Numerical data are presented for four resins and 26 solvents that correlate well with observed solubility behavior. Using this model, it is also possible to construct “solubility maps,” and these are also discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760231504
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  • 4
    Electronic Resource
    Electronic Resource
    Regulation of production of a platelet-derived growth factor-like protein by cultured bovine aortic endothelial cells (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 121 (1984), S. 298-308 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Platelet-derived growth factor (PDGF) is a potent mitogen for cultured cells of mesenchymal origin. Known sources of PDGF or PDGF-like protein are blood platelets, several transformed cell lines, and cultured endothelial cells (EC). We have examined the regulation of production of a PDGF-like protein in cultures of bovine aortic EC using a specific radioreceptor assay for PDGF. EC constitutively secreted PDGF-like protein into serum-containing or serum-free medium. The rate of production of PDGF-like protein was constant for at least 3 weeks and was not due to release of an internal store, since cell lysis by repeated freeze/thaw cycles did not relase significant amounts of the protein. Synthesis of PDGF-like protein was sensitive to changes in the pH of the media and was maximal at pH 8.5. Production of PDGF-like protein was independent of EC growth rate: rapidly dividing cells and confluent, quiescent cells produced equal amounts per cell. However, sparse, quiescent EC produced more PDGF-like protein per cell than did confluent, quiescent cells. Several phorbol esters stimulated production of PDGF-like protein. At a concentration of 10-6 M, a twofold stimulation was observed upon addition of the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) and nearly a fourfold stimulation upon addition of the nonpromoting analog, methyl TPA. Incubation of EC with endotoxin (10 μ/ml) resulted in a twofold stimulation of PDGF-like protein production. In all experiments with endotoxin and phorbol esters, an increase in the production of PDGF-like protein was accompanied by morphological changes in the EC cultures. The cells appeared elongated and fibroblastic and exhibited low viability. A mathematical model was developed in which PDGF-like protein production was shown to consist of two separate components - production at a constant rate by healthy cells and a large burst of synthesis and secretion by dying cells. These results suggest that injurious agents may be capable of stimulating production of a growth factor by the endothelium.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041210206
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Biochemical properties of the endothelium-derived growth factor: Comparision to other growth factors (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 114 (1983), S. 339-345 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cultured bovine aortic endothelial cells (BAEC) can be maintained at saturation density for several weeks in the absence of serum. These cells retain viability and normal culture morphology, and continuously produce a growth factor for mesenchymally derived cells-the endothelium-derived growth factor (EDGF). The amount and specific activity of EDGF that is produced by BAEC under serum-free conditions remains constant for weeks. The levels of EDGF produced under these serum-free conditions is equivalent to levels produced in medium containing 5% plasma-derived serum. EDGF has been found to be trypsin sensitive, acetone and ammonium sulfate precipitable, and resistant to heat and sodium dodecyl sulfate treatment. Gel filtration on Sephacryl S-200 in the presence of formic acid (1%) yields two major peaks of activity corresponding to proteins of apparent molecular weights of approximately 24,000 and 14,000 daltons. This chromatographic step affords a ten-to 12-fold purification with a combined recovery of greater than 85%. Unlike brain or pituitary fibroblast growth factor, EDGF activity is destroyed by dithiothreitol or periodic acid. EDGF is not a somatomedin since it exhibits no detectable sulfation activity in a porcine cartilage assay. EDGF is not inhibited by antiserum to epidermal growth factor and is capable of stimulating DNA synthesis in a 3T3 variant cell line that is nonresponsive to and lacks receptors for epidermal growth factor. The majority of EDGF activity does not behave like the platelet-derived growth factor during ion exchange chromatography. Antisera prepared in rabbits and in mice to human platelet-derived growth factor has little effect on bivine or human EDGF activity. These biochemical and immunological properties of EDGF indicate that it is distinct from several other well-characterized polypeptide growth factors.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041140313
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  • 6
    Electronic Resource
    Electronic Resource
    The intracellular ratio of the membrane to the secreted form of immunoglobulin M heavy chain is a measure of the developmental stage of B cell lymphomas (1982)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 3 (1982), S. 53-68 
    Details
    ISSN: 0192-253X
    Keywords: B cell development ; immunoglobulin M ; B cell tumor ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Tumors of B lymphocyte origin have been used as models for normal B cells “frozen” at particular stages of their development. Surface properties, amount, and intracellular location of immunoglobulin and the synthesis of J chain have all been used as indicators of developmental stages. Each requires special techniques or yields data that are difficult to compare from one experiment to the next. For these reasons, we have developed a metric for B cell development that is simple to perform and allows quick quantitative comparisons of cell lines.It has recently been established that the membrane (μm) and secreted (μs) forms of the IgM heavy chain differ at their extreme carboxy termini. The two proteins differ slightly in size and are easily distinguished when they are compared without their carbohydrate on sodium dodecyl sulfate (SDS) polyacrylamide gels. We have examined four mouse tumors derived from the B lymphocyte lineage whose phenotypes resemble late pre-B cells (internal μ only; uninduced 70Z/3), small B lymphocytes (high levels of surface IgM; LPS-induced 70Z/3, WEHI 231), lymphoblasts (both membrane and secreted IgM; WEHI 279.1), and plasma cells (copious IgM secretion; MOPC 104E). Despite the fact the 70Z/3 and WEHI 231 secrete no detectable IgM, all of the tumors synthesize at least intracellular forms of both μm and μs. The proportion of μm is stable and is characteristic of each tumor. The 70Z/3 cells and WEHI 231 cells synthesize about 75% of their total μ as μm; WEHI 279.1 cells synthesize about 30% and MOPC 104E cells about 5% of their total μ as μm. The population of LPS-stimulated B lymphocytes shows a similar progression during its differentiation. The proportion of μm correlates with other developmentally regulated parameters (Fc receptor, Ia and plasma cell antigen levels, and J chain) and can be used as a simple metric for comparison with developing B lymphocytes and determination of the developmental stage of a B cell tumor.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020030106
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  • 7
    Electronic Resource
    Electronic Resource
    Rigid PVC lubricants - an empirical viewpoint (1982)
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 4 (1982), S. 124-127 
    Details
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Field observations of lubricant type and level control are presented with the intent of promoting laboratory routes to developing better rigid formulations. Calcium stearate is identified as a gelation promoter. PE wax is described as a very effective gelation retarder. POPE is an effective slip agent, ineffective retarder, and slight promoter. It is obvious that more understanding of the functions of lubricants is needed to permit on-line formulation adjustment.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/vnl.730040309
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