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  • Brassica napus  (4)
  • Engineering General  (4)
  • Physics  (4)
  • Cell & Developmental Biology  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 80 (1990), S. 465-469 
    ISSN: 1432-2242
    Keywords: Microspore-derived population ; Fatty acids ; Inheritance ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The inheritance of major fatty acids in seed triglycerides was studied in three homozygous microspore-derived populations of spring rapeseed (Brassica napus L.). Crosses were made among parents with contrasting amounts of erucic, oleic, linoleic and linolenic acids. Microspores from F1 plants were cultured, and haploid plants were colchicine-doubled to provide homozygous populations reflecting F1 gametic arrays for fatty acid genotypes. Segregation ratios of the gametic arrays for specific fatty acid contents were compared to hypothetical models by the Chi-square test. Segregation pattern confirmed that erucic acid levels were controlled by two major loci, each having two alleles with additive effects. Oleic acid segregation indicated control of accumulation by at least two segregating genetic systems, one acting on chain elongation and the other involving desaturation. Accumulations of erucic acid and oleic acid were influenced by the same two loci, which control the chain elongation steps leading from oleic acid to erucic acid. Oleic acid was further influenced by at least two additional segregating loci involved in control of desaturation of oleic acid to form linoleic acid. Segregating alleles at loci involved in desaturation had a much smaller influence on oleic acid content than alleles segregating at loci controlling, the elongation of oleic acid to erucic acid. In a population free of erucic acid, the segregation pattern of linoleic acid levels fit a model involving segregating alleles at two loci. In contrast, segregation for linolenic acid content fits a three-locus additive model. In this study, microspore culture technology provided a rapid method of defining F1 gametic segregation for inheritance analyses.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5060
    Keywords: Brassica napus ; oilseed rape ; doubled haploids ; fatty acids ; microspore-derived population ; single seed descent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Microspore embryogenesis technology allows plant breeders to efficiently generate homozygous micros-pore-derived breeding populations of oilseed rape (Brassica napus L.) without traditional generations of inbreeding. This study was conducted to compare the frequency distribution of microspore-derived population and single seed descent populations with respect to fatty acids of seed oil. Both microspore-derived populations and single seed descent populations were produced from each of three crosses made between selected parents containing contrasting amount of erucic, oleic, linoleic and linolenic acids. The fatty acid content of F3 plants derived lines (F5 seed) developed by single seed descent was compared to that of microspore-derived populations. The means, ranges and distribution pattern of seed fatty acid contents were similar in both populations for each fatty acid studied, although a few heterozygous lines were observed in the single seed descent populations. The results indicated that microspore-derived population form random, homozygous F1 plant derived gametic arrays for all fatty acids evaluated. Selection for altered fatty acid composition in microspore-derived and single seed descent homozygous populations should be equally efficient, in the absence of linkage of traits investigated.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5060
    Keywords: Brassica napus ; rapeseed fatty acid accumulation ; microspore-derived embryo ; zygotic seed ; triacylglyceride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Microspore culture of rapeseed (Brassica napus L.) has provided a powerful tool not only for breeding but also in developmental studies. In this study, microspore-derived embryos (MDE) of B. napus were evaluated as a model in seed for studying accumulations of triacylglyceride (TAG) fatty acids in both a low and high erucic acid rapeseed line; and accumulations of TAG and free fatty acids (FFA) in a high erucic acid rapessed line. The accumulation patterns confirmed that MDE had a similar TAG fatty acid profile to seed during the embryo development within each genotype. The oil accumulation in MDE after 36 days in culture (DIC) approached levels similar to those in zygotic seed 25 days after flowering (DAF). Significant differences were detected in contents of both total free fatty acids and specific free fatty acids between MDE and seed. During the developmental period, total free fatty acids changed from 16% to 2.1% in MDE, but from 10.5% to 0.1% in seed. MDE had much higher percentage of free linolenic and erucic acids than seed, particularly during the late developmental stages. The current study indicated that MDE can be used as a model to study TAG and TAG fatty acids in seed but caution must be taken to study free fatty acid metabolism.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell, tissue and organ culture 31 (1992), S. 141-149 
    ISSN: 1573-5044
    Keywords: Brassica napus ; cryopreservation ; in vitro embryo ; microspore ; rapeseed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microspore cryopreservation is a potentially powerful method for long-term storage of germplasm for in vitro embryo production in plant species. In this study, several factors influencing embryo production following the ultra-low temperature (−196 °C in liquid nitrogen) storage of isolated microspores of rapeseed (Brassica napus L.) were investigated. Microspores were prepared in cryogenic vials and subjected to various cooling treatments before immersion in liquid nitrogen for varying periods. Efficiency of microspore cryopreservation was reflected by in vitro embryo production from frozen microspores. Of all the cooling treatments, microspores treated with a cooling rate of 0.25% °C/min and a cooling terminal temperature of −35 °C before immersion in liquid nitrogen produced the highest embryo yields (18% and 40% of unfrozen controls in two genotypes, respectively). Fast thawing in a 35 °C water bath was necessary to recover a high number of embryos from microspore samples being frozen at a higher cooling rate, while thawing speed did not affect samples after freezing at a slower cooling rate. The storage density of cryopreserved microspores affected embryo production. Storage at the normal culture density (8×104 microspores/ml) was less efficient for embryo production than at high densities (4×106 microspores/ml and 1.6×107 microspores/ml), although no significant difference was found between the high densities. Evaluation of plant lines derived from frozen microspores indicated no variation in isozyme pattern and no enhanced cold tolerance of these lines. Isolated microspores of B. napus could be stored for extended period for in vitro embryo production.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 23 (1986), S. 831-846 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: As an effort to predict effectively the actual collapse load of a structure, a series of numerical studies on the stability of shell structures are made. The difference in formulation between the two types of linear buckling loads, the classical and the fully linearized, is first demonstrated. Their correlations with respect to the actual stability limit of the structure are compared, and finally the two types of critical load approximations are obtained at various stages of a nonlinear analysis to study the pattern of convergence to the actual collapse load. It is found that the fully linearized buckling analysis, when combined with nonlinear analysis, can serve as a useful tool for prediction of the stability limit of a structure. While for most types of structures the approximation is within engineering accuracy, the rate of convergence of the extrapolated critical load also gives some insight to the accuracy of the approximation.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 25-29 
    ISSN: 1040-452X
    Keywords: Hemizona assay (HZA) ; Rhesus monkey ; Oocyte ; Sperm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The hemizona assay (HZA) in Rhesus monkeys was employed to study the correlation of zona-binding ability with sperm motility or with naturally developing oocytes at various maturational stages. Oocytes from unstimulated ovaries were retrieved within 2 hr from monkeys sacrificed for vaccine production (in reproductive season, but with their menstrual cycles not determined). Oocytes were divided into four groups based on their morphological maturation: 1) Oocytes surrounded by more than one cumulus layer (MC); 2) Oocytes retaining intact germinal vesicle nuclei (GV); 3) Oocytes with germinal vesicle breakdown showing distinct perivitelline space (PVS); and 4) Oocytes extruding the first polar body (PBI). The mean numbers of sperm bound to hemizona for PB1, PVS, GV, and MC groups were 132.9 ± 12.0, 71.5 ± 10.1, 36.1 ± 4.0, and 20.1 ± 2.9 (Mean ± SE), respectively. The four groups showed significant differences from each other in sperm/egg binding ability (P 〈 0.01). The number of bound sperm significantly increased with oocyte maturation. The present study also showed that zona-binding ability was also affected by sperm motility. For sperm with 67.7% motility and sperm with 31.2% motility, the average numbers of bound sperm were 43.5 ± 2.2 and 25.3 ± 2.9 (Mean ± SE), respectively. There was significantly higher binding ability for sperm with higher motility (P 〈 0.01). The results suggest that: 1) The rhesus monkey model can serve as a very sensitive model for studying sperm/egg interaction by HZA; 2) Sperm motility positively correlated with sperm/egg binding; and 3) Sperm/egg binding ability increases with oocyte maturation. The binding ability is highest when oocytes matured to the PB1 stage, which is also the best opportunity for fertilization. This is strong evidence for the “zona maturation” hypothesis. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 27 (1990), S. 110-117 
    ISSN: 1040-452X
    Keywords: Rabbit embryos ; Hypertonic sucrose ; Micromanipulation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rabbit zygotes and embryos were exposed to hypertonic sucrose in phosphate-buffered saline (SPBS). In experiment one, 144 zygotes shrank to 32-36% of their initial volume in 1.0 M SPBS within 30 min. Neither hypertonic treatment with 0.5 M or 1.0 M SPBS nor micropuncture of the zona pellucida after shrinkage affected embryo development into blastocysts in vitro (88%, 83%, and 82%, respectively), compared to that of the controls (93%, P 〉 .05). In experiment two, 252 two- to four-cell- and 177 morula-stage embryos were exposed to isotonic PBS control or 0.5 M, 1.0 M, or 1.5 M SPBS for 30, 60, 90, 120, and 150 min before transfer to PBS (290 mOsm). Embryo development was significantly reduced (P 〈 .05) when embryos were exposed in 0.5 M and 1.0 M SPBS for more than 60 min or in 1.5 M SPBS for more than 30 min. In experiment 3, morulae exposed for 60 min to 0.5 M or 1.0 M SPBS shrank to 37-39% or 32-35% of their initial volume and then expanded to 87-94% or 81-90% of their initial volume, respectively, after being returned to isotonic PBS for 60 min, but embryos in 1.5 M SPBS had erratic osmotic behavior. In experiment four, 192 two- to four-cell embryos exposed to 0.5 M SPBS for 0, 30, and 60 min before transfer to oviducts of recipients resulted in the production of 39%, 42% and 31% young, respectively (P 〉 .05). Exposure of embryos to 0.5 M sucrose for 60 min clearly does not compromise developmental potential and can simplify and speed up micromanipulation procedures.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 11 (1995), S. 479-490 
    ISSN: 1069-8299
    Keywords: Modal reaction method ; modal participation factor ; support motion ; discrete system ; modal equivalent mass ; quasi-static decomposition ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An efficient method, called the modal reaction method, for calculating the modal participation factors for support motion problems is proposed. It is found that modal reactions at supports proportionally describe the magnitudes of the modal participation factors. Thus, the modal participation factor for support motion problems can be calculated very efficiently, saving more than 99 per cent, for the given example with 640 degreees of freedom, of the CPU time compared with using the popular quasistatic decomposition method.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 134 (1988), S. 189-199 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth of tissue culture TO-2 cells derived from the warm water fish Tilapia, the induction of thermotolerance, and protein synthesis profiles of these cells in response to temperature changes were examined. TO-2 cells can grow between 15 to 34°, with an optimal growth temperature of 31°. There is no apparent killing of the cells when the temperature is lowered to 4° for up to 3 days. Survival of TO-2 cells at 43° was studied after various preheat treatments: (1) acute heating at 40° for 15 min followed by 31° incubation, (2) chronic exposure at 37° for several hr, or (3) long-term thermal adaptation at 34°. The cells acquire thermotolerance from pre-exposure to 37° for as short as 6 hr. Preheating at 40° followed by incubation at 31° also induces thermotolerance against a subsequent 43° heat challenge. In addition, 34° thermal adapted cells are resistant to 43° heating. One- and two-dimensional gel electrophoresis of proteins after heat treatments show that three major heat shock proteins with molecular weights around 87, 70, and 27 kD are preferentially synthesized. The synthesis of two additional proteins with an isoelectric point of 6.9 and molecular weights of 60 and 44 kD are significantly enhanced in 34° thermal-adapted and 37° chronic heated cells, but not in cells subjected to an acute heat shock at either 40° or 43°. On the other hand, the 27 kD heat shock proteins are mainly present in the 43°, 40°, and 37° heat-shocked cells, but not in the 34° thermal-adapted cells.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 39 (1996), S. 847-865 
    ISSN: 0029-5981
    Keywords: interlaminar shear stress ; layer reduction technique ; composite laminate ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Interlaminar stress plays an important role in the delamination failure of laminated composites. A recently presented theory, the Interlaminar Shear Stress Continuity Theory (ISSCT), can directly and accurately predict interlaminar shear stresses in laminated composites by the constitutive equations. The present study further generalizes the derivation to a complete form from which many displacement-based laminate theories can be derived. Most of all, both the single-layer and multiple-layer approaches are incorporated into the analysis in the thickness direction. The laminate is discretized into several sublaminates and, then, a layerwise theory is applied in the analysis of this reduced laminate. This reduction in the number of layers used in the analysis makes the calculation of interlaminar shear stresses on the interested interface in a thick laminate more efficient. In addition, numerical solutions in closed-form and finite element form for laminates under cylindrical bending and bidirectional bending are examined. It is found that in the thickness direction the cubic order of the interpolation function and the discretization with four to six sublaminates can reduce the computational efforts dramatically and retain the accuracy of the predicted stresses within ±8 per cent.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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