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  • 1
    Electronic Resource
    Electronic Resource
    ADRENAL CORTICAL-ANTERIOR PITUITARY RELATIONSHIPS DURING EMBRYONIC LIFE (1952)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 55 (1952), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1952.tb26530.x
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  • 2
    Electronic Resource
    Electronic Resource
    A bioluminescent chaetognath (1994)
    [s.l.] : Nature Publishing Group
    Nature 367 (1994), S. 225-226 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - The ability to produce light is especially widespread among marine zoo-plankton, where the only major phylum without a luminous species has been thought to be the Chaetognatha1. These carnivorous arrow worms are found throughout the world's oceans, where their abundance approaches that of ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/367225a0
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  • 3
    Electronic Resource
    Electronic Resource
    Control of flashing in fireflies (1981)
    Springer
    Journal of comparative physiology 144 (1981), S. 287-298 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The restrained male of the fireflyPteroptyx cribellata of Papua New Guinea responds to exogenous light signals with a latency of about one second, which equals the period of the natural spontaneous rhythm of flashing and includes about 800 ms of central nervous delay. The response is cycle-by-cycle and all-or-none and the duration of the response time is independent of the phasing of the driver in relation to the free run rhythm (Figs. 1, 2). The firefly can be entrained to rhythms over a period range of 800 ms to 1,600 ms, during which it leads or lags the concurrent signal by an amount equal to the difference between the driving period and the animal's period (Figs. 3, 4). The phase-response line is nearly straight and is inclined 45 ° (Figs. 2, 5). Normally an exogenous signal dictates interflash timing but occasionally may fail to entrain the firefly (Figs. 7B, E) or may fail to evoke a flash (Figs. 7F, G). Persistence of endogenous control of timing period duration even during driving is occasionally seen as spontaneous drift in response time (Fig. 9). It is proposed that during entrainment each exogenous signal resets the pacemaker immediately to the start of its endogenous cycle, from which point it then begins a new series of free run periods. Thus each flash is timed in relation to the signal of the preceding cycle (Fig. 3). We devised a model of the endogenous timing cycle which fits the empirical data and achieves entrainment by a single mechanism involving phase advance or delay rather than change in actual rate of endogenous timing (Fig. 12). The proposed mechanism by which single males entrain to light signals seems compatible also with the mass synchronous flashing which is the characteristic behavior of field congregations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00612560
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  • 4
    Electronic Resource
    Electronic Resource
    Luminescent microsource activity in bioluminescence of the dinoflagellate,Pyrocystis fusiformis (1982)
    Springer
    Journal of comparative physiology 145 (1982), S. 517-527 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The basis for the different bioluminescent flash forms previously described inPyrocystis fusiformis was examined using image intensification and microphotometric analysis. 2. The unique kinetics (10 ms rise time and biphasic decay) of the first flash (FF) from a mechanically stimulated night phase cell resembled the kinetics of light emission from the individual microsources (microflashes). 3. Synchronous light emission by microsources during the FF was replaced by their asynchronous flashing during subsequent flashes (SFs). Microsource kinetics changed to a skewed, bell-shaped microflash with a 40 ms rise time. The whole cell flash (macroflash) was of similar form but had slower kinetics than the microflash due to the asynchronous summing of microflashes, resulting in the 150 ms rise time characteristic of SFs. 4. All microsources appeared to flash during the FF. Microsource emission during SFs was temporally unpredictable. A given microsource might or might not flash during an SF and could flash several times per stimulus. The dimness of SFs immediately following the FF resulted from a decrease in the number of active microsources. Potentiation of SFs with stimulus intervals of 1 min or less involved increasing numbers of active microsources. Fatigue occurred as a result of decreasing numbers of active microsources and decreasing microflash emission strength. 5. Submaximal mechanical stimulation produced localized luminescent activity. Microsources responded as with maximal stimuli: initially with FF kinetics and synchrony, followed by SF kinetics and asynchrony. At frequencies of 0.33 pps and faster, the area of local luminescent activity enlarged with each stimulus, causing microsources in the new region of activity to respond as with an FF while the previously stimulated microsources exhibited SF kinetics and asynchrony. 6. The long-term glow produced by acid-stimulated cells resulted from prolonged asynchronous activity of the microsources. Acid-stimulated microflashes displayed SF kinetics even with the first flash of a microsource. 7. Recovery of FF kinetics occurred with a transition from asynchronous to synchronous coordination that was almost complete after 6 min. The transition from SF to FF microflash kinetics required longer recovery and was not abrupt, but exhibited intermediate kinetics. 8. A model is presented as a guide to further study of bioluminescence control in this dinoflagellate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00612817
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  • 5
    Electronic Resource
    Electronic Resource
    Two flash forms in the bioluminescent dinoflagellate,Pyrocystis fusiformis (1981)
    Springer
    Journal of comparative physiology 143 (1981), S. 43-52 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. A method was developed for studying bioluminescent activity in single cells of the dinoflagellate,Pyrocystis fusiformis. Individuals were isolated in holding tubes in day phase and held without stimulation until bioluminescence was maximally excitable, between circadian time (CT) 14 and CT 22, where CT 0 designates daybreak. Mechanical stimulation, via a pulse generator controlled solenoid, was applied to individual cells that had received no prior excitation in the night phase tested. 2. Two different flash forms were recorded. The first flash (FF) in response to a mechanical stimulus was very bright and had a rise time of 10 ms, and a biphasic decay that was 90% complete approximately 200 ms from flash onset. The form of subsequent flashes in response to further stimuli differed radically from the FF. They were dimmer and longer lasting than the FF with approximately 150 ms rise times and a monotonic decay that was 90% complete as long as 500 ms from flash onset. 3. Cells responded with one flash per mechanical stimulus and recordings were made until the response was exhausted. Total mechanically stimulated luminescence (TMSL) was measured with a digital integrator. TMSL and the integral of the FF were functions of cell size. 4. The degree of potentiation and number of flashes per cell were functions of stimulus frequency. At higher stimulus frequencies cells produced fewer flashes and more light per flash. The effects of potentiation were long lasting, persisting for stimulus intervals of up to one minute. 5. At slow stimulus frequencies (one pulse per 48 s) bioluminescent activity was not totally exhausted during the 8 h night phase test period. With prolonged stimulation a fatigued flash form developed that combined elements of the FF and subsequent flashes. 6. Cells that were stimulated to exhaustion recovered some bioluminescent capacity once stimulation ceased. Initial recovery was rapid and cells stimulated after only a 15 min recovery period produced as many flashes in the second stimulus series as in the first even though their TMSL was reduced 82%. Therefore, the number of flashes a cell produced was not simply proportional to the amount of bioluminescent material available. 7. The unique FF kinetics recovered with time, requiring 30–60 min in unfatigued cells and more than 6 h in fatigued cells. With a 24 h recovery period FF kinetics were more dependent on the cell receiving a normal 12 h day phase than was TMSL recovery. 8. Mechanically triggered bioluminescence inPyrocystis fusiformis appeared to be the result of at least two temporally distinct processes, one of which was dependent on a precharging period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606067
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  • 6
    Electronic Resource
    Electronic Resource
    Control of flashing in fireflies (1981)
    Springer
    Journal of comparative physiology 144 (1981), S. 277-286 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Males of the fireflyPteroptyx cribellata of Papua New Guinea luminesce spontaneously in two principal modes: a regular one-per-second display flash (Fig. 1 A) and an irregular flicker of 3–10 peaks per second (Fig. 1B). In free run rhythmic display flashing by intact, restrained individuals, serial correlation analysis of interflash duration in successive cycles indicates that the variability of the brain-to-lantern excitation delay is negligible in comparison with the variability of the endogenous timing process (Figs. 6, 7). It is therefore possible to use the duration of the flash-to-flash interval of the intact firefly as a measure of endogenous pacemaker timing behavior. It is deduced that the cycling of the pacemaker is continuous, does not require that the animal see his own flash or even that he flash (Fig. 2 A), shows intercycle independence (Fig. 5) and may phase-shift its rhythm spontaneously upon occasion (Fig. 2C). Pacemaker period is normally distributed (Fig. 3), is not correlated with flash intensity, and appears to shorten slightly if a flash is skipped (Table 3). The occurrence of spontaneous flash skipping is taken to indicate that the timing process that measures pacemaker period can cycle independently of its usual triggering of the flash-excitation message to the lantern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00612559
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  • 7
    Electronic Resource
    Electronic Resource
    Optical parameters of euphausiid eyes as a function of habitat depth (1984)
    Springer
    Journal of comparative physiology 154 (1984), S. 307-318 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The relationships between habitat depth, eye diameter relative to body length, and the dimensions of rhabdoms and crystalline cones have been examined for 13 species of three oceanic euphausiid genera with habitats ranging from near-surface waters to the deep-sea. Rate of eye growth decreases with depth. Longer rhabdoms may increase the visual sensitivity to point and extended light sources by an eye of a particular size with depth. Larger interommatidial angles suggest that visual acuity decreases at depth. Depth-related changes in euphausiid eyes are considered with respect to the probable roles of vision and bioluminescence in the deep-sea. Unusual features of the eyes of several species are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00605230
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  • 8
    Electronic Resource
    Electronic Resource
    Optical parameters of the eyes of some benthic decapods as a function of habitat depth (Crustacea, Decapoda) (1985)
    Springer
    Zoomorphology 105 (1985), S. 108-113 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eye diameter relative to body length, and interommatidial angle, rhabdom length and rhabdom width as a function of eye size, were determined for specimens of 19 benthic macruran decapod species in 8 genera and 5 families, spanning a wide range of habitat depths. For these species, eye diameter relative to body length tends to increase with adult habitat. In addition, rate of eye growth relative to body growth increases with habitat depth, a trend opposite to that of pelagic crustaceans previously investigated. Interommatidial angle decreases with increasing eye diameter, and therefore with depth for an individual of a particular size. Rhabdom length and width tend to increase with eye diameter. Visual sensitivity may increase with depth among these species as a result of both larger eyes and the associated increase in rhabdom dimensions. Differences in energetic limitations and visual environments might produce the difference in trends of eye size relative to body size between benthic and pelagic crustaceans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312145
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  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructure of the larval firefly light organ as related to control of light emission (1975)
    Springer
    Cell & tissue research 164 (1975), S. 27-44 
    Details
    ISSN: 1432-0878
    Keywords: Insect bioluminescence ; Adrenergic synapse ; Photocyte ultrastructure ; Neuroeffector ; Firefly light organ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The firefly larva has a pair of light organs consisting of a layer of interdigitating, light emitting cells, covered dorsally with a layer of opaque, white cells. Each light organ is ventilated by one large and several smaller tracheal branches and is innervated by a branch of the segmental nerve containing two axons. These axons branch profusely in the photocyte layer so that several nerve profiles are seen around any photocyte. Nerve terminals contain large dense-core vesicles and small light-core vesicles. Clusters of light-core vesicles surrounding irregularly shaped membrane densifications, presumably the synapses between nerve and photocyte, are common in nerve terminals. Light emitting cells in insects characteristically contain photocyte vesicles. In the larva there are both full and empty photocyte vesicles; the full vesicles contain a matrix with tubular membrane invaginations in contrast to the empty vesicles which contain amorphous membrane invaginations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221693
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  • 10
    Electronic Resource
    Electronic Resource
    Pharmacomorphological study of denervation induced by 6-hydroxydopamine in Porichthys photophores (1976)
    Springer
    Cell & tissue research 166 (1976), S. 365-388 
    Details
    ISSN: 1432-0878
    Keywords: 6-hydroxydopamine ; Photophores ; Fish ; Bioluminescence ; Pharmacology ; Adrenergic control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of 6-hydroxydopamine (6-OHDA) on the bioluminescent response of Porichthys photophores were investigated as part of a pharmacological study of the neural control of luminescence in this fish. Subcutaneous injections of 6-OHDA induce a luminescent response similar to that of norepinephrine (NE), suggesting a sympathomimetic action. The luminescent response to electrical stimulation is almost completely and irreversibly abolished within 24 hours following low-dose treatment of the photophores with 6-OHDA, while the sensitivity of these organs to exogenous NE is increased significantly over the few days post-treatment. During this period the photophores continuously emitted a steady low-level glow. Electronmicroscopic studies of such photophores revealed progressive destruction of the nerve endings. Photophore luminescent sensitivity to NE subsequently became sub-normal, and at this stage electron microscopy revealed an increasingly larger number of damaged photocytes, supportive cells and, in one case, lens cells. From these results it is suggested that 6-OHDA initially impairs neuro-photocyte transmission by destroying catecholaminergic nerve endings. In turn, the transmitter reuptake mechanism is also impaired, thus accounting for development of supersensitive responses to exogenous NE. Subnormal luminescent responses to NE appear as a result of loss of photocyte competence due to structural deterioration. The latter are interpreted as the consequence of removal of trophic factors supplied by the photophore adrenergic innervation. Suppression of luminescent response to both electrical stimulation and exogenous NE in photophores treated with higher doses of 6-OHDA, may be due to a direct effect of this drug on the receptor sites of the photocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220132
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