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  • 1
    Electronic Resource
    Electronic Resource
    Survival of frozen-thawed bovine red cells as a function of the permeation of glycerol and sucrose (1974)
    Springer
    The journal of membrane biology 15 (1974), S. 137-158 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Bovine red cells, like other cells, exhibit maximum survival when frozen at certain optimum rates. Cells cooled more slowly are apparently injured by alterations in the cytoplasm or surrounding medium such as the increased concentration of solutes induced by extracellular ice formation. Additives like glycerol protect against this “slow” freezing injury. It has been generally believed that such protection requires permeation by the additive, but we have found that this supposition is not valid for the bovine red cell. Cells were suspended in 1, 2 or 3m glycerol at 20, 15 or 0°C for 0.7 to 30 min or more and then frozen to −196°C at 43 or 1.7°C/min. In nearly all cases, the percentage survival after thawing was as high for cells held in glycerol for 1 min or less prior to freezing as for cells held in glycerol for 30 min, and it was as high for cells held at 0°C as for cells held at 20°C. Survivals were the same for these times and temperatures of exposure in spite of the fact that the osmolal ratio of glycerol to salts in the cell after 30 min at 20°C, for example, was as much as 800 times greater than that in cells held at 0°C for 0.7 min. In addition, the survival after a contact of 1 or 30 min with 2.3 osmolal sucrose was the same as that after exposure to 2.3 osmolal glycerol even though the bovine red cell is impermeable to sucrose. Although exposures of 1 and 30 min to glycerol yielded similar survivals, exposures for intermediate times produced a transitory but dramatic decrease in survival. The dip occurred after longer periods of incubation when the concentration of glycerol was increased and when the incubation temperature was decreased. No dip was evident in cells chilled to 0°C or in cells frozen in sucrose. Thus, the dip seems to be associated in some way with partial permeation of glycerol prior to freezing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01870085
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  • 2
    Electronic Resource
    Electronic Resource
    Permeability of the bovine red cell to glycerol in hyperosmotic solutions at various temperatures (1974)
    Springer
    The journal of membrane biology 15 (1974), S. 107-136 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary A central tenet in cryobiology is that low-molecular-weight protective solutes such as glycerol must permeate cells in high concentration in order to protect them from freezing injury. To test this supposition, it is necessary to estimate the amount of solute that has permeated a cell prior to freezing. The amount in bovine red cells was estimated from the flux equation $${{ds} \mathord{\left/ {\vphantom {{ds} {dt}}} \right. \kern-\nulldelimiterspace} {dt}} = P_\gamma A[(activity external solute) - (activity internal solute)].$$ Solving the equation required estimates ofP γ, the permeability constant for the solute. Estimates for glycerol in bovine red cells were made in two ways: (1) by measuring the time to 50% hemolysis of red cells suspended in isosmotic or hyperosmotic (1 to 3m) solutions of glycerol that were hypotonic with respect to NaCl, and (2) by measuring the time required for red cells in hyperosmotic solutions of glycerol in isotonic salinebuffer to become susceptible to osmotic shock upon 10-fold dilution with isotonic saline-buffer. The measurements were made at 0, 10, 15 and 20°C. The values by the second technique ranged from 2.3×10−6 cm/min to 2.7×10−6 cm/min at 20°C, depending on the concentration of glycerol. The values by the first technique were 0 to 30% lower. Both techniques yielded about the same activation energy for permeation between 0 and 20°C, 21 kcal/mole. This is equivalent to a halving of the permeation rate for every 5° drop in temperature. Expressing the flux equation in the formulation of irreversible thermodynamics changed the value ofP by less than 10%, probably because σ, the reflection coefficient, is 0.95 at 25°C. Expressing the driving force as the difference in molality or osmolality of glycerol, rather than as the difference in activity, however, had somewhat greater effects on the numerical values ofP, but had no effect on the activation energy. It is concluded that estimates ofP based on differences in activities and on the osmotic shock technique are the least subject to error. The use of the usual irreversible thermodynamic equations to express the flux may be a misleading refinement, in that the assumptions underlying them become questionable for concentrations of glycerol as high as 1, 2, or 3m.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01870084
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  • 3
    Electronic Resource
    Electronic Resource
    Cell division and plant development from protoplasts of carrot cell suspension cultures (1972)
    Springer
    Planta 103 (1972), S. 348-355 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cell regeneration and sustained division have been observed in protoplasts from carrot cell suspension cultures. Carrot plants were produced from the protoplasts by embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386707
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  • 4
    Electronic Resource
    Electronic Resource
    Embryogenesis and production of albino plants from cell cultures of Bromus inermis (1970)
    Springer
    Planta 95 (1970), S. 355-358 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Embryogenesis occurs in cells from brome grass grown in suspension culture in defined medium. Exogenous hormones are not required. The embryos develop into plants which lack chlorophyll.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384708
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  • 5
    Electronic Resource
    Electronic Resource
    Second discovery of multiple sex chromosomes among fishes (1972)
    Springer
    Cellular and molecular life sciences 28 (1972), S. 223-225 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Bei einer bisher nicht beschriebenen mexikanischen Fischart werden 41 Autosomen beim Männchen und 42 beim Weibchen gefunden. Die Befunde sprechen für ein System multipler Sexualchromosomen dieser Fische.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01935773
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  • 6
    Electronic Resource
    Electronic Resource
    Immunological methods for the agglutination of protoplasts from cell suspension cultures of different genera (1973)
    Springer
    Planta 112 (1973), S. 45-56 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protoplasts from cell suspension cultures of Vicia hajastana Grossh., soybean (Glycine max L.) and brome grass (Bromus inermis Leyss.) were tightly agglutinated by immune sera prepared against them in rabbits. After incubation, the aggregated protoplasts became adpressed over a considerable area of their surface. Antibody prepared against Vicia protoplasts agglutinated both Vicia and soybean protoplasts alone, as well as a mixture of the two. Soybean and bromegrass antibody likewise cross-reacted with and agglutinated Vicia protoplasts. The heterologous reactions were nearly as strong as, and in some cases stronger than, the homologous. When sheep anti-rabbit globulin was reacted with a mixture of the protoplasts previously coated with homologous antibody, agglutination occurred much more quickly and the aggregates could not be dispersed without physical damage. Carbol-fuchsin staining of nuclei showed that Vicia and soybean protoplasts were randomly mixed in the aggregate. The protoplasts were viable and underwent division after the antibody treatment. The immune serum, which presumably contained complement, lysed the protoplasts unless it was heat-treated prior to use.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386030
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  • 7
    Electronic Resource
    Electronic Resource
    Numerical experiments in collisionless systems (1971)
    Springer
    Astrophysics and space science 14 (1971), S. 73-90 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649196
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  • 8
    Electronic Resource
    Electronic Resource
    Ecological energetics of the seaweed zone in a marine bay on the Atlantic coast of Canada. III. Energy transformations by sea urchins (1973)
    Springer
    Marine biology 18 (1973), S. 99-114 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An energy budget was constructed for a population of the sea urchin Strongylocentrotus droebachiensis in the nearshore area of St. Margaret's Bay, Nova Scotia, Canada. Of the 6 age classes identified, ages 1+and 2+accounted for about 1/2 the population energy flow. Population production efficiencies were: production/assimilation=0.28, production/consumption=0.04 to 0.13, and production/biomass=0.80. Although S. droebachiensis was the dominant herbivore in the seaweed bed, it utilized only 1 to 7% of seaweed production. As with other populations of sea urchins, however, it had a proportionately greater influence on seaweed biomass, and also presumably production, by clearing seaweed from large areas of substrate and maintaining it clear. Loss of dissolved organic matter, the only term in the energy budget not measured, was estimated by substracting the other terms in the energy budget from consumption. In laboratory individuals, this ranged from 40 to 80% of absorption (consumption-faeces). A critical review of energy budgets for 6 other species of marine benthic grazers also revealed large amounts of energy unaccounted for that might be attributed to loss of dissolved organic matter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00348685
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  • 9
    Electronic Resource
    Electronic Resource
    The influence of soil micro-organisms on the growth and chemical composition of soybean (1970)
    Springer
    Plant and soil 32 (1970), S. 146-160 
    Details
    ISSN: 1573-5036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A plastic film isolator was adapted for the growth of soybeans in sterile soil, sterile reinoculated soil, and unsterilized soil. The presence of micro-organisms significantly increased the mass of tops and roots as well as the plant content of Ca, Mg, Fe, Al, Cu, Zn, and Mo. Plant content of N, P, and K was not affected by microbial activity, while manganese, made available by steam-sterilization, was oxidized to unavailable forms by the soil microflora. The mixed microflora influenced the quantity and distribution of free amino acids within the plant but did not affect the distribution of amino acids within the crude protein fraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01372853
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  • 10
    Electronic Resource
    Electronic Resource
    The influence of soil micro-organisms on the growth and chemical composition of soybean (1970)
    Springer
    Plant and soil 32 (1970), S. 146-160 
    Details
    ISSN: 1573-5036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A plastic film isolator was adapted for the growth of soybeans in sterile soil, sterile reinoculated soil, and unsterilized soil. The presence of micro-organisms significantly increased the mass of tops and roots as well as the plant content of Ca, Mg, Fe, Al, Cu, Zn, and Mo. Plant content of N, P, and K was not affected by microbial activity, while manganese, made available by steam-sterilization, was oxidized to unavailable forms by the soil microflora. The mixed microflora influenced the quantity and distribution of free amino acids within the plant but did not affect the distribution of amino acids within the crude protein fraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01372853
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