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1.
1.  We have discovered a previously unreported visual mutant of the blowfly,Calliphora erythrocephala. It shows a reduced or absent visual performance, e.g., in escape and optomotor behavior. The effects of this mutation on the ultrastructure were studied by electron microscopy (Figs. 3–8) and on electrophysiological function, by intracellular recordings (Figs. 1 and 2).
2.  The genetic basis of this spontaneous mutation was studied by test crosses of mutant and wild-type flies. The defect appears to be in an autosomal recessive gene (Table 1).
3.  Of the mutant stock studied soon after eclosion (n = 18) 35% shows optomotor reactions, whereas only 6% studied in later life (n = 240) shows any optomotor behavior.
4.  The absence of the receptor potentials in photoreceptor cells is not directly associated with structural disorders in the early life of these mutant flies, but several types of degenerative changes are manifested in the retinular cells later on. The optomotorically blind specimens have normal (about –60 mV) resting membrane voltages but no detectable receptor cell voltage response to light, indicating a block in phototransduction. The spectral and polarization sensitivities of optomotor-positive flies are normal (Fig. 2).
5.  At the beginning of degeneration the number of lysosomes in the receptor cells is increased compared with normal flies, but their number as well as that of other components of the cell interior decrease later on. During the progression of the degeneration, the rhabdomeres shrink while the mitochondria swell and disintegrate (Figs. 6–8).
6.  The blocking of phototransduction is proposed to lead to disturbance of the turnover of the rhabdomeres and finally to degeneration of the receptor cells.
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2.
1.  We studied the response of plurisegmental interneurons in the suboesophageal ganglionic mass of female spiders (Cupiennius salei) to male vibratory courtship signals.
2.  The opisthosomal vibrations (low frequency component) and the pedipalpal percussions (high frequency component) are processed in parallel by interneuron type I and type II, respectively (Figs. 3, 7).
3.  Type III, IV and V interneurons represent the macrostructure of the male courtship signals (Figs. 8, 9, 10), i.e. the beginning and the end of a series (type III, V) or the end of the series only (type IV). The macrostructure is known to influence the response probability of the female. The spontaneous bursting activity of a type VI neuron undergoes slow and long lasting changes upon stimulation with natural courtship signals (Fig. 11).
4.  Many interneurons responded to natural signals but not to behaviourally effective computer models. This is presumably due to the lack of spectral complexity of the model compared to natural signals. Differences in the natural conspecific and heterospecific signals, however, are represented by the neuronal response (Fig. 3).
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3.
1.  The actions of GABA on three classes of visual interneurons in crayfish, Procambarus clarkii, medulla externa are examined. The effect of GABA on the visual response is compared to GABA's action on agonist-elicited responses purported to mediate the visual response.
2.  GABA produces a shunting type of inhibition in medullary amacrine cells which is associated with a small depolarization (Figs. 2, 3), a large increase in input conductance (Gn) and a reversal potential close to rest (Fig. 4). GABA is a potent antagonist to the depolarizing action of acetylcholine (ACh) (Fig. 5).
3.  GABA depolarizes dimming fibers (Fig. 2), and the response is mediated by an increase in Gn (Fig. 6). GABA antagonizes the light-elicited IPSP and the hyperpolarizing action of ACh (Fig. 7).
4.  Sustaining fibers (SF) do not appear to have GABA receptors but GABA inhibits the excitatory visual input pathway to the SFs (Fig. 8). Conversely, the GABA antagonist, bicuculline, potentiates the SF light response (Fig. 9).
5.  GABA has at least three different modes of antagonist action in the medulla: i) Increased conductance and depolarization in dimming fibers and medullary amacrine neurons; ii) Decreased chloride conductance in tangential cells; and iii) An inhibitory action on the visual pathway which drives SFs.
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4.
1.  A 28-kDa peptide from the brain of the tobacco hornworm,Manduca sexta, was purifiedvia HPLC. The peptide copurified with the insect neurohormone, prothoracicotropic hormone (PTTH), through two HPLC columns.
2.  Immunocyctochemistry using polyclonal antibodies against the 28-kDa peptide revealed that the peptide was produced in the same protocerebral neurons that produce PTTH. Western blot analysis demonstrated that the 28-kDa peptide and big PTTH are different molecules.
3.  A PTTHin vitro bioassay indicated that despite having chromatographic properties similar to those of big PTTH and being produced by the same neurons, the 28-kDa peptide did not have PTTH activity.
4.  Amino acid sequence analysis yielded a 27 N-terminal amino acid sequence that had no similarity with known peptides.
5.  Immunocytochemical studies revealed that the 28-kDa peptide is present as early as 30% embryonic development and is absent by adult eclosion. This is in contrast to big PTTH, which is expressed throughout theManduca life cycle.
6.  These data suggest that the 28-kDa peptide is another secretory phenotype of the lateral neurosecretory cell group III (L-NSC III) which may have functions distinct from those for big PTTH or may act synergistically with big PTTH.
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5.
Locusts (Locusta migratoria) were flown in a flight simulator which converts yaw torque into angular motion of the visual environment (Fig. 1). The modalities and the time-course of steering behavior under these closed-loop conditions have been investigated.
1.  Locusts flying under visual closed-loop conditions stabilize their visual environment by performing correctional steering manoeuvres. Besides torque production, due to differential wing movements and ruddering, correctional steering also involves head movements (Fig. 6).
2.  During open-loop steering, ruddering and yaw torque begin some 60 ms after the onset of the visually simulated deviation from course. Head movements occur some 90 ms after stimulus onset, i.e. some 30 ms later than yaw torque (Figs. 3, 5) and therefore do not initiate thoracic steering outputs.
3.  Open- and closed-loop correctional steering do not differ in their behavioral components or temporal organization (Figs. 2, 6, Table 1).
4.  In the absence of major disturbances, correctional steering under closed-loop conditions is performed with minimal ruddering (only a few degrees in amplitude), that probably produces little or no aerodynamic drag (Fig. 6).
5.  Locusts prevented from moving their heads still stabilize their visual environment in the closed-loop situation. However, the precision of steering is affected by this constraint (Figs. 8, 9, 10, 12). Head immobilization also alters the temporal coordination of correctional steering (Figs. 7, 11).
6.  These results show that head movements, in addition to their generally accepted role in vision improvement, also contribute to the precision and temporal coordination of correctional flight manoeuvres. The mechanism is partly via proprioceptive feedback.
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6.
1.  The activity of tympanal high- and low-frequency receptors in the migratory locustLocusta migratoria was recorded with glass capillary microelectrodes, and Lucifer Yellow was then injected through the microelectrode to reveal the cells' metathoracic projections.
2.  A photodetector device was used to monitor the abdominal respiratory movements, which caused clearly visible deflections of the tympanal membrane.
3.  The auditory receptors respond not only to sound stimuli but also to the respiratory movements; these phasic (Figs. 1–3) or tonic (Fig. 4) responses are especially pronounced during the inspiration and expiration movements, and less so during the constriction phases.
4.  The magnitude of the response to sound depends on the phase of the stimulus with respect to the respiratory movements. At certain phases sound elicits no response at all (Fig. 5).
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7.
1.  Tethered flies (Musca domestica) walking on an air-suspended ball show a spontaneous response to the e-vector of polarized light presented from above, i.e. a slowly rotating e-vector induces periodic changes in the flies' turning tendency. Suitable control experiments exclude the possibility that the response is elicited by intensity gradients in the stimulus (Figs. 1 and 2).
2.  Presence of the e-vector response in both white and UV light and its complete absence in yellow light equally support the concept that the specialized dorsal rim area of the compound eye with its highly polarization sensitive UV receptors R7marg and R8marg mediates polarization vision in flies (Fig. 3).
3.  E-vector orientations inducing no turning response additional to the fly's inherent turning tendency are either parallel (avoided e-vector) or perpendicular (preferred e-vector) to the animal's body axis (Figs. 1 and 4).
4.  Considering the fanlike arrangement of the microvillar orientations of R7marg and R8marg in the dorsal rim area of the eye of Calliphora and Musca, a stabilizing function of polarization vision in controlling the flight course is suggested and discussed in the context of results from other behavioural studies.
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8.
1.  An extracellular recording and staining technique has been used to study the structure of individual ventral-cord elements in the auditory pathway ofLocusta migratoria.
2.  Three groups of auditory ventral-cord neurons can be distinguished: (a) neurons ascending to the supraesophageal ganglion, (b) T-shaped neurons, and (c) neurons limited to the thoracic ventral cord.
3.  The ventral-cord neurons ascending to the supraesophageal ganglion link the auditory centers of the thorax to those of the supraesophageal ganglion. These are, at least in part, richly arborized neurons of large diameter.
4.  The ventral-cord neurons with T structure send equivalent signals along both arms of the T; they resemble the neurons of the first group in that they make synaptic connections in the supraesophageal ganglion, but they also conduct auditory information to caudal regions of the thorax via the descending trunk of the axon.
5.  In the supraesophageal ganglion there are several extensive projection areas of the auditory ventral-cord neurons. No direct connections to the mushroom bodies, the central body or the protocerebral bridge could be demonstrated.
6.  The thoracic ventral-cord neurons act as short segmental interneurons, providing a connection between the tympanal receptor fibers and the ascending and T-shaped ventral-cord neurons. They play a crucial role in auditory information processing.
7.  The possible functional properties of the various morphological sections of the auditory ventral-cord neurons are discussed, with reference to their connections with motor and other neuronal systems.
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9.
1.  The behaviour of isolated individual forager honeybees during the night has been investigated with a variety of experimental methods. Prolonged rest in these diurnal insects is accompanied by: reduced muscle tone (Figs. 1, 6, 10–12), decreased motility (Figs. 2, 3, Table 1), lowered body temperature (Figs. 7, 8) and raised reaction threshold (Fig. 9). These phenomena strongly resemble four characteristic features of sleep in humans, mammals and birds. It is thus very likely that the profound rest which forager bees experience at night is sleep. This assumption is further supported by the results of previous investigations of visual interneurones in the bee.
2.  The antennae of sleeping bees manifest characteristic postural constellations (Fig. 6). High reaction thresholds are associated with particular antennal positions.
3.  The total sleep time (duration of antennal immobility plus duration of small antennal movements) in 24 h for two bees was 7.6 h and 4.9 h (Table 1).
4.  Bees which rest in a hive at night also display phenomena which have been encountered during the laboratory investigations.
5.  Sleep in mammals is an active, controlled process; the same seems to be true of sleep in honeybees (Figs. 3, 4). Unlike mammals, bees experience their deepest sleep towards the end of the sleep phase (Figs. 3, 9, 10, 12).
Dedicated to Prof. Dr. D. Burkhardt on the occasion of his 60th birthday  相似文献   

10.
1.  While collecting nectar in hovering flight the European hawk moth Macroglossum stellatarum efficiently regulates its distance relative to flowers that are shaken by wind. This can be demonstrated in laboratory experiments by moving dummy flowers (blue cardboard disks) towards and away from the feeding animal (Fig. 1).
2.  Distance regulation is predominantly mediated by visual cues. Mechanoreceptors on the proboscis appear to contribute little to the response.
3.  Movements of dummy flowers can be simulated by expanding and contracting a pattern projected onto a screen. With this technique we investigated the dynamical properties of the servo mechanism underlying distance regulation. The system behaves as a bandpass filter with corner frequencies of 0.15 and 5 Hz (Figs.2,3).
4.  When a high-speed ramp-like movement of the flower is simulated, there is an asymmetry in the response. During simulated approach the reaction is phasic-tonic with a pronounced overshoot at the beginning, during simulated retraction it remains tonic (Fig.5B,C).
5.  During distance regulation the animals compensate for the speed of the edge of the projected pattern. Distance regulation improves substantially when the number of stimulated elementary movement detectors is increased through increasing the number of contour lines by projecting concentric rings instead of a homogeneous disk (Figs.7, 8).
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11.
1.  Bees were trained to enter the central hole in a disc containing 89 holes and collect sugar-water from a box placed behind it (Fig. 1). Visual marks were offered on the inner surface of a cylinder placed in front of the disc (Fig. 2), thus projecting onto peripheral (nonfrontal) regions of the bees' eye. The trained bees were tested by recording their choices among the holes.
2.  Bees use the memorized position of peripheral marks to localize the frontally positioned goal (Figs. 6–9). The effectiveness of a mark depends on its retinal position, the most effective marks being lateral ones (Figs. 8, 9).
3.  Altering the dimensions of the mark does not influence the distribution of the bees' choice (Figs. 11–13). Thus, image motion rather than image size is used for distance estimation in the present task.
4.  Cinematographic recordings (Fig. 14) revealed that the searching bees' whereabouts are correlated with the choice distribution (Fig. 6a). The hypothesis that the bees stabilize the mark in the trained retinal position by correcting for retinal image slip is proposed.
5.  Experiments using coloured patterns revealed that the bees' performance is mediated by the green-sensitive channel (Figs. 17–22), as predicted by the above hypothesis.
Dedicated to Prof. Dr. Rüdiger Wehner on the occasion of his 50th birthday, in great appreciation for both his scientific work and his personality.  相似文献   

12.
1.  The self-adapting effects of chemical backgrounds on the response of primary chemoreceptor cells to superimposed stimuli were studied using lobster (Homarus americanus) NH4 receptor cells.
2.  These receptors responded for several seconds to the onset of the backgrounds, and then returned to their initial level of spontaneous activity (usually zero). The strongest response always occurred only during the steepest concentration change; the response then decayed back to zero or to the earlier spontaneous firing level, while the background concentration was still rising, and remained silent during the entire time that the background was maintained constant (20–30 min) (Fig. 2).
3.  Exposure to constant self-adapting backgrounds eliminated the responses of NH4 receptor cells to stimuli of concentration lower than the background, and reduced the responses to all higher stimulus concentrations tested by a nearly equal amount. This resulted in a parallel shift of the stimulus-response function to the right along the abscissa (Figs. 3 and 4).
4.  Since the response threshold was completely re-set by adaptation to backgrounds, NH4 receptors seem to function mostly as detectors of relative rather than absolute stimulus intensity across their entire dynamic range: the response to a given stimulus-to-background ratio remained the same over 3 log step increases of background concentration (Fig. 6).
5.  As in other sensory modalities, a parallel shift of response functions appears to be an important property of chemoreceptor cells, allowing for this sensory system to function over a wider stimulus intensity range than the instantaneous dynamic range of individual receptor cells.
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13.
1.  The physiology and morphology of olfactory interneurons in the brain of larval Manduca sexta were studied using intracellular recording and staining techniques. Antennal olfactory receptors were stimulated with volatile substances from plants and with pure odorants. Neurons responding to the stimuli were investigated further to reveal their response specificities, dose-response characteristics, and morphology.
2.  We found no evidence of specific labeled-lines among the odor-responsive interneurons, as none responded exclusively to one plant odor or pure odorant; most olfactory interneurons were broadly tuned in their response spectra. This finding is consistent with an across-fiber pattern of odor coding.
3.  Mechanosensory and olfactory information are integrated at early stages of central processing, appearing in the responses of some local interneurons restricted to the primary olfactory nucleus in the brain, the larval antennal center (LAC).
4.  The responses of LAC projection neurons and higher-order protocerebral interneurons to a given odor were more consistent than the responses of LAC local interneurons.
5.  The LAC appears to be functionally subdivided, as both local and projection neurons had arborizations in specific parts of the LAC, but none had dendrites throughout the LAC.
6.  The mushroom bodies and the lateral protocerebrum contain neurons that respond to olfactory stimulation.
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14.
In the grasshopperChorthippus biguttulus the stridulatory movements of males with surgically manipulated ventral nerve cords were investigated.
1.  The stridulation pattern of animals with a hemisected mesothoracic ganglion was indistinguishable from that of intact animals.
2.  After hemisection of the metathoracic ganglion several animals were still able to stridulate in the species-specific pattern (Figs. 3, 5). Different structural elements of the song, however, were affected to different degrees by this operation. Although the stereotyped up-and-down movements were normal, the rhythm of pauses, which in intact animals are inserted after every third to fourth up- and-down cycle, was disturbed. As a result, the variation of syllable lengths was much higher (Fig. 4).
3.  A prominent feature after hemisection of the metathoracic ganglion was an almost complete loss of coordination between left and right hind legs (Figs. 5–7). Only in the coarse structure of the song (e.g. the beginning and termination of song sequences) was a correlation of the leg movements still discernible. This was especially obvious in songs of the rivalry type and in precopulatory kicking movements (Fig. 8).
4.  If in addition to hemisection of the metathoracic ganglion one of the neck connectives was transected the animals stridulated only with the hind leg ipsilateral to the intact connective (Fig. 11).
5.  Even after hemisection of both the meso- and metathoracic ganglia, animals were able to produce the species-specific stridulation pattern (Fig. 9).
6.  In animals with hemisected metathoracic ganglia and both connectives between pro- and mesothoracic ganglia transected, components of the species-specific pattern could be induced by current injection into the mesothoracic ganglion (Fig. 10).
7.  These results suggest that the stridulation rhythm-producing neuronal network is composed of hemisegmental subunits. A hemiganglionic structure of rhythm generators might reflect the ancestral organization of locomotion-controlling networks.
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15.
Intracellular recordings have been made of responses to step, ramp and sinusoidal changes of light by second-order L-neurones and a third-order neurone, DNI, of locust (Locusta migratoria) ocelli.
1.  The membrane potential at the peak response by an L-neurone to a change in light is proportional to the light increment or decrement, independent of background, over a range of at least 4 log units. As background increases, response latency and time-course decrease, and responses become more phasic (Fig. 1).
2.  Adaptation to a changed mean light level involves a change in sensitivity and a slow change in resting membrane potential, which never adapts completely to dark resting potential in the presence of light (Fig. 3).
3.  L-neurones can follow changes in light which last several seconds, but responses to fast changes are enhanced in amplitude (Figs. 4, 5). An increase in background light causes an increase in the frequency of sinusoidally modulated light at which the largest response occurs (Fig. 4).
4.  The responses of DNI to increased light saturate at lower intensities than those of L-neurones. During adaptation to different background light intensities, there is no change in the input-output relation of the synapse between an L-neurone and DNI (Figs. 6, 7).
5.  For a rapid decrease in light, DNI produces a rebound spike, followed by a period of silence (Figs. 5, 8).
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16.
1.  The larva of the tiger beetle (Cicindela chinensis) possesses six stemmata on either side of the head. Optical and physiological properties of two pairs of large stemmata and a pair of anterior medium sized stemmata, and responses of second-order visual interneurons (medulla neurons) have been examined.
2.  Objects at infinite distance were estimated to focus 50 m deep in the retina in the large stemmata. Receptive fields of four large stemmata, the acceptance angle of each being 90°, largely overlapped one another.
3.  The stemmata possessed a single type of retinular cell with a maximal spectral sensitivity at 525 nm, and a flicker fusion frequency of 25–50 Hz.
4.  Medulla neurons expanded fan-shaped dendrites in the medulla neuropil, and their axons extended into the protocerebrum. They responded to illumination with a variety of discharge patterns. They also responded with spike discharges to moving objects and to apparent movements provided by sequential illumination or extinction of LEDs. They did not show directional selectivity. They possessed well-defined receptive fields ranging from 30° to 105°.
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17.
Evidence is presented here from experiments on the visual system of the fly that questions participation of the large monopolar cells (LMCs) in the optomotor response.
1.  The response of a directionally-selective motion-detecting neuron (H1) in the lobula plate to small sudden jumps of a grating is directionally-selective (Fig. 1), indicating that at least one of the inputs to each of the elementary movement detectors (EMD) that feed into H1 must deliver a tonic signal. The responses of LMCs to the same stimulus are, however, entirely phasic (Fig. 2).
2.  In dual electrode experiments on Eristalis, injection of current into an LMC does not change the spiking rate of H1. Induction of spiking activity, or injection of current into an LMC, which alters the cell's response to a flash of light from a point source, does not affect the response of H1 to the same flash (Figs. 3, 4).
3.  The temporal properties of LMCs differ markedly from those of the optomotor response and of directionally-selective movement — detecting neurons in the lobula plate (Figs. 6, 9).
4.  There is poor correlation between LMC degeneration and the strength of the optomotor response in a mutant of Drosophila (Fig. 8).
5.  The optomotor response of Drosophila is strongly polarization sensitive, but Drosophila LMCs show no polarization sensitivity (Fig. 11).
While our results do not exclude the participation of the LMCs in the optomotor response, they do indicate that at least one other lamina channel that is tonic and/ or polarization sensitive must be involved.  相似文献   

18.
3DFS is a 3D flexible searching system for lead discovery. Version 1.0 of 3DFS was published recently (Wang, T.; Zhou, J. J. Chem. Inf. Comput. Sci., 1998, 38, 71–77). Here version 1.2 represents a substantial improvement over version 1.0. There are six major changes in version 1.2 compared to version 1.0.
1.  A new rule of aromatic ring recognition.
2.  The inclusion of multiple-type atoms and chains in queries.
3.  The inclusion of more spatial constraints, especially the directions of lone pairs.
4.  The improvement of the query file format.
5.  The addition of genetic search for flexible search.
6.  An output option for generating MOLfiles of hits.
Besides the above, this paper supplies:
1.  More query examples.
2.  A comparison between genetic search and Powell optimization.
3.  More detailed comparison between 3DFS and Chem-X.
4.  A preliminary application of 3DFS to K+ channel opener studies.
Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s0089490050231  相似文献   

19.
1.  The terminal ganglion ofLocusta migratoria contains a number of non-giant, wind-sensitive, ascending and local interneurones. Six ascending (Figs. 1, 2) and 6 local (Figs. 6, 7) interneurones have been identified morphologically on the basis of intracellular stains with Lucifer Yellow.
2.  The physiological responses of the various cell types were recorded as the cerci were exposed to sound, wind, or electrical stimulation (Figs. 3, 8). Some cells summate the input from both cerci (Fig. 3), while others are excited by input from one side and inhibited by input from the other (Fig. 8). Conduction velocities for several non-giant ascending interneurones range from 1.5 m/s (cell 1) –2.1 m/s (cell 25).
3.  The morphologies and physiological responses of giant (GIN 1) and non-giant ascending interneurones (cells la, b) with somata in cluster 1 of neuromere 9 were compared using simultaneous intracellular recordings (Figs. 2A, 4). These neurones have very similar dendritic arborizations (Fig. 4A, B), and respond almost identically to cercal stimulation (Fig. 4Ci), but there do not appear to be any connections with GIN 1 (Fig. 4Cii, iii).
4.  The morphology (Fig. 5A, C), and response to cercal stimulation by wind (Fig. 5B) of a nongiant interneurone (cell 7) with its soma in cluster 1 of segment 8 (Fig. 5), are very similar to those of cluster 1 cells such as GIN 1 in segment 9.
5.  Of the 6 local interneurones (Figs. 6, 7) all except one (cell 9) have bilateral arborizations which may extend over several neuromeres within the ganglion (cells 10, 22). Several of the interneurones (cells 5, 9, 24) do not produce action potentials in response to cercal stimulation (Figs. 8, 10) or injection of depolarizing current (Fig. 11).
6.  Simultaneous recordings from pairs of interneurones demonstrate that giants and locals (GIN 2/cell 5; GIN 1/cell 9), as well as different local interneurones (cell 24/cell 5), receive input from the same wind-sensitive filiform afferent (Fig. 9).
7.  Local interneurones 5 and 22 are in different neuromeres of the terminal ganglion but have a similar gross morphology (Figs. 6, 7, 10). Cell 5, however, has arborizations projecting into both posterior cercal glomeruli (Fig. 7 A, inset), whereas only the ipsilateral branches of cell 22 extend posteriorly to the cercal glomerulus (Fig. 10C). Physiologically, cell 5 is depolarized by wind directed at both cerci (Fig. 10 A), cell 22 mainly by wind directed at the ipsilateral cercus (Fig. 10C). Cell 5 does not produce action potentials in response to wind whereas cell 22 does.
8.  Cell 5 occurs as a bilateral pair in the terminal ganglion (Figs. 7B, inset; 11). Simultaneous recordings of the bilateral homologues show that they share the input of at least one wind-sensitive filiform afferent (Fig. 11D), and that there are no connections between them (Fig. 11E). Simultaneous penetrations of local interneurone 5 and giant interneurones demonstrate a short-latency excitatory connection from GIN 3 to cell 5 (Fig. 12 A), and a long-latency excitatory connection from GIN 2 to cell 5.
9.  The roles of giant and non-giant interneurones in transmitting information to thoracic motor centres are discussed.
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20.
Müller  D. G.  Frenzer  K. 《Hydrobiologia》1993,(1):37-44
Culture studies with healthy and virus-infected isolates of Ectocarpus siliculosus, Feldmannia simplex and F. irregularis gave the following results:
–  Virus particles are produced in deformed reproductive organs (sporangia or gametangia) of the hosts and are released into the surrounding seawater.
–  Their infective potential is lost after several days of storage under laboratory conditions.
–  New infections occur when gametes or spores of the host get in contact with virus particles. The virus genome enters all cells of the developing new plant via mitosis.
–  Virus expression is variable, and in many cases the viability of the host is not impaired. Infected host plants may be partly fertile and pass the infection to their daughter plants.
–  Meiosis of the host can eliminate the virus genome and generate healthy progeny.
–  The genome of the Ectocarpus virus consists of dsDNA. Meiotic segregation patterns suggest an intimate association between virus genome and host chromosomes.
–  An extra-generic host range has been demonstrated for the Ectocarpus virus.
–  Field observations suggest that virus infections in ectocarpalean algae occur on all coasts of the world, and many or all Ectocarpus and Feldmannia populations are subject to contact with virus genomes.
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