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  • 1995-1999  (3)
  • 1950-1954
  • 1995  (3)
  • 1950
  • Barley  (1)
  • Coccinellidae  (1)
  • Contralateral  (1)
Material
Years
  • 1995-1999  (3)
  • 1950-1954
Year
  • 1995  (3)
  • 1950
  • 1
    ISSN: 1432-1106
    Keywords: Motoneuron ; Stretch reflex ; Cutaneous ; Contralateral ; Spinal ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of bilateral focal cooling of dorsolateral thoracic spinal cord on segmental reflex pathways to the triceps surae muscles were assessed in decerebrate cats from the reflex forces produced by single shocks or trains of electrical stimuli applied to the ipsilateral caudal cutaneous sural and the contralateral tibial nerves. The validity of the dorsal cold block technique as a substitute for acute surgical dorsal hemisection was established by showing that focal cooling reliably reproduced the stretch-induced “clasp knife” inhibition of triceps surae reflexive force seen following dorsal hemisection. Under control (warm) conditions, the inhibitory components of electrically evoked ipsilateral sural and contralateral tibial reflexes faded rapidly during sustained trains, with a resultant production of large-amplitude reflex force as measured from either the entire triceps surae or from the medial gastrocnemius muscle alone. Dorsal cold block greatly reduced the amplitude of reflexive force evoked by sustained electrical stimulation of either nerve. Indeed, the cold block completely reversed the sign of train-evoked reflexes to a net inhibition of reflex force output in one-half of the sural and one-half of the contralateral tibial stimulation experiments. Peak transient forces evoked by single shocks to the sural or contralateral tibial nerves were also sometimes reduced, but this result was more variable than for prolonged nerve stimulation. The persistence of activity in segmental inhibitory pathways during dorsal cold block, as indicated by instances of reflex sign reversal, suggests that descending bulbospinal pathways traversing the dorsolateral funiculi may be responsible for “fading” of segmental inhibitory reflex components in decerebrate cats with intact spinal cords during sustained afferent input. The possibility that the enhanced magnitude and duration of segmental inhibition during cold block will increase the likelihood of disruption of the size principle for motoneuron recruitment is also discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 185 (1995), S. 194-204 
    ISSN: 1615-6102
    Keywords: Barley ; Nucleoli ; Proteins ; Roots ; Stress ; “Weightlessness”
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cells of carrot calli (Daucus carota L.) grown on clinostats (simulated weightlessness) exhibit increases in nucleolar number and volume. In clinostat-grown whole barley plants (Hordeum vulgare L. cv. Steptoe), nucleoli in ∼70% of root meristem and root cortical cells in the 1 mm root apex exhibit multiple nodulations after one day of growth. The nucleolar nodules (1.1 μm mean diameter) are densely and finely fibrous, distinctly different from the nucleolus in which the content is so compact that the granular component is masked. Control nucleoli (from vertically rotated and stationary seedlings) rarely exhibit nodule-like protrusions, are not compact, and contain a well defined granular component. Proteins that are heat soluble, characteristic of many stress responses, rapidly increase in barley grown on clinostats. Barley growth on clinostats is slowly and steadily inhibited. There is no difference between vertically rotated and stationary controls for any of the parameters measured, indicating that clinostat motion per se does not affect significantly barley development. The evidence taken together suggests that barley plants germinated and grown on clinostats are stressed, the effects of which are expressed sequentially by alteration of nucleolar morphology, increased production of heat-soluble proteins, and decreased plant growth. Similar stress-related changes may be expected to occur in plants subjected to weightlessness during space flight. It is therefore of interest that nucleoli in wheat roots (Triticum aestivum L. cv. Broom) obtained from the space flight IML-1 mission show irregularity that is not observed in any of the ground controls for the flight experiment.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-8248
    Keywords: Coccinella trifasciata ; Coccinellidae ; developmental threshold ; degree-days ; isofemale lines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé L'effet de la température sur le développement deCoccinella trifasciata (provenant de Corvallis, Oregon) a été étudié pour la population générale et comparé entre lignées isofemelles. Aucum œuf ne survit à 10 et 34°C. Le taux de survie est compris entre 63,3% et 96,7% pour des températures situées entre 18 et 34°C. La durée du développement, de la ponte à l'état adulte, dure de 44,2 jours à 18°C à 11,1 jours pour une température de 34°C. Le poids moyen de l'adulte ne change pas en fonction de la température et il est de 15,2 mg. Pour l'espèce, les besoins pour le développement complet de l'œuf à l'adulte, sont de 227 degrés-jour au-dessus du seuil de développement de 12,7°C. Les valeurs de ce seuil diffèrent entre les lignées isofemelles et sont comprises entre 11,4 et 14,5°C pour des durées se situant entre 186 et 260 degrés-jour au-dessus des seuils respectifs. La lignée isofemelle ayant la vitesse de développement larvaire la plus rapide à 18°C est caractérisée par un besoin de 260 degrés-jour au-dessus du seuil de 11,4°C. Celle ayant la vitesse de développement la plus lente à 18°C est caractérisée par un besoin de 186 degrés-jour au-dessus du seuil de 14,5°C. L'intérêt de l'utilisation de lignées isofemelles dans l'élevage d'agents de lutte biologique est discuté.
    Notes: Abstract Temperature-dependent development ofCoccinella trifasciata LeConte from Corvallis, Oregon, was assessed for the general population and compared among a subset of isofemale lines. All eggs died at 10 and 34°C. Survival ranged between 63.3–96.7% from 18–34°C. Development from oviposition to adult ranged from 44.2 days at 18°C to 11.1 days at 34°C. Mean adult weight did not differ among temperatures, and was 15.2 mg overall. For the species, heat-unit requirements for development from egg to adult were 227 degree-days above a developmental threshold of 12.7°C. Values for the developmental threshold differed among isofemale lines, and ranged from 11.4–14.5°C with heat-unit requirements ranging from 186–260 degree-days above their respective threshold. The isofemale line producing the fastest rate of immature development at 18°C was characterized by a heat-unit requirement of 260 degree-days above a developmental threshold of 11.4°C. The isofemale line producing the slowest rate of immature development at 18°C was characterized by a heat-unit requirement of 186 degree-days above a developmental threshold of 14.5°C. Implications of using isofemale lines in culturing biological control agents are discussed.
    Type of Medium: Electronic Resource
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