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1.
1.  The uropod righting reaction of the crayfish,Procambarus clarkii, was investigated in response to stimulation of proprioceptors at the bases of the walking legs and to stimulation of the balance organs, the statocysts.
2.  Tilting a platform beneath the legs of crayfish elicited movements of the exopodites of the uropods in the horizontal plane. These were produced by activity only in the slow opener and closer muscles of the exopodites, the fast muscles not being involved in the formation of the uropod pattern. Platform tilts (±20°) with the axis of rotation parallel to the transverse axis of the body elicited a symmetrical closing of the exopodites when the anterior leg groups were depressed, and a symmetrical opening when the same leg groups were levated.
3.  Platform tilts parallel to the longitudinal axis of the body elicited asymmetrical movements of the uropods with the exopodite ipsilateral to the levated legs opening and the contralateral exopodite closing. In all experiments the responses of the uropods were only reliably elicited when accompanied by extension of the abdomen.
4.  The influence of input from various leg groups was examined by raising them from the oscillating platform in various combinations. The strongest reflex drive came from the 4th and 5th pairs of walking legs. The major source of input came from the coxo-basipodite (C-B) joint of the walking legs. Blocking other leg joints (mero-carpopodite (M-C) and carpo-propodite (C-P)) had no obvious effects on the normal response.
5.  Tilting animals in the roll plane (±20°), with no leg contact, produced an opening of the exopodite on the upward side and a closing of the exopodite on the downward side. Responses were again only reliably elicited when accompanied by abdominal extension, and were produced by activity only in the slow opener and closer muscles.
6.  Previously identified statocyst interneurones (C1 and C2) were recorded in the circumoesophageal commissures. No modulation of their spontaneous activity by leg input could be detected.
7.  Results suggest that separate pathways from the leg proprioceptors and the statocyst organs to the uropods exist and converge at a late stage in the pathway, within the terminal (6th) abdominal ganglion.
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2.
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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3.
1.  The excitatory and inhibitory influences on the gill ofAplysia Juliana, which are mediated by the branchial nerve, were studied by means of electrophysiological techniques. Excitatory and inhibitory pathways in the nerve were stimulated simultaneously or selectively.
2.  The branchial nerve was found to contain both excitatory and inhibitory pathways which did not contain synapses in the branchial ganglion. The excitatory pathways caused longitudinal shortening of the gill along the efferent branchial vessel and the inhibitory pathways were modulatory, depressing the longitudinal shortening.
3.  Branchial nerve stimulation elicited two types of excitatory junctional potential (EJP), which were not mediated by the branchial ganglion, in a muscle cell of the efferent branchial vessel. One type was attributed to the central motor neuron and the other type to a motor neuron which is probably situated in the neural plexus of the gill periphery.
4.  Four inhibitory pathways from the central nervous system to the gill were found.
5.  Inhibitory junctional potentials (IJPs) recorded from muscle cells of the efferent branchial vessel in response to branchial nerve stimulation did not have monosynaptic characteristics. It is thought that inhibitory motor neurons which were activated by the branchial nerve might exist at the neural plexus of the gill.
6.  A single EJP which has been induced by a stimulus pulse applied to the excitatory pathway of the branchial nerve may be depressed in an all-or-none manner by a stimulus pulse applied to the inhibitory pathway, if this is done within a distinct short period prior to or after the stimulus inducing the EJP. This indicates that the central motor neuron receives presynaptic inhibition at its periphery.
7.  The motor neurons of the neural plexus seem to receive inhibitory innervation. Suppression of endogenous EJPs in the efferent vessel persisted for a long period even after cessation of stimulation.
8.  A certain branchioganglionic neuron (BGN) was found to receive inhibitory postsynaptic potential (IPSP) inputs from the branchial nerve.
9.  The multimodality of both the excitatory and the inhibitory pathways in the branchial nerve may explain the compound neural modulations of gill movements.
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4.
We have identified a nerve carrying auditory afferents and characterized their physiological responses in the tiger beetle,Cicindela marutha.
1.  The tympana are located at the lateral margins of the first abdominal tergum. The nerve carrying the tympanal afferents is a branch of the dorsal root from the first abdominal ganglion.
2.  Both male and female auditory afferent responses are sharply tuned to 30 kHz with sensitivities of 50–55 dB SPL.
3.  The auditory afferents show little adaptation and accurately code the temporal characteristics of the stimulus with the limit of a resolution of 6–10 ms.
4.  The difference in threshold between contralateral and ipsilateral afferents for lateral stimuli is greatest at 30 kHz and is at least 10–15 dB.
5.  Ablation studies indicate that the floppy membrane in the anterolateral corner of the tympanum is crucial for transduction while the medial portion of the tympanum is less important.
6.  The tiger beetle and acridid (locust and grasshopper) ears have evolved independently from homologous peripheral structures. The neural precursor of the tympanal organs in both animals is likely the pleural chordotonal organ of the first abdominal segment.
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5.
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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6.
The wind-orientated walk of carrion beetles Necrophorus humator F. was analysed under closed-loop conditions with a walking compensator and under openloop conditions with a paired tread wheel (Fig. 1).
1.  On the walking compensator an animal runs stable courses with a preferred direction relative to an air current (velocity =; 100 cm/s, Fig. 2B-D). A change in the air-current direction causes a corresponding adjustment of the mean walking direction (Fig. 3). Such course adjustment works best for changes in the air-current direction by an absolute value of 90° (Table 2).
2.  Under closed-loop conditions the animal shows deviations of less than ± 45° around its preferred direction relative to the wind (Fig. 2B-D). The characteristic curve which describes the animal's angular velocity as a function of the animal's walking direction relative to the air-current stimulus is therefore revealed only in this angular range (Fig. 3, top).
3.  Under open-loop conditions, however, complete characteristic curves can be obtained because the animal's walking reaction in response to any given angle of air-current stimulus is measurable on the paired tread wheel (Fig. 4). The characteristic curves are approximately sinusoidal functions. They can either show a shift parallel to the ordinale by a superimposed direction-independent constant angular velocity alone or, at the same time, they can independently exhibit an angular shift along the abscissa (Fig. 5).
4.  The walking tracks straighten with increasing air-current velocity (Fig. 6A, insets), i.e. the animal more rapidly compensates deviations from a preferred course. This corresponds to higher amplitudes of the characterisic curve and steeper slopes at the negative zero-crossing point under open- as well as under closed-loop conditions (Fig. 6).
5.  Walking in an air-current field can be explained by a model of the course control system using a feedback loop (Fig. 7). This model operates according to a sinusoidal characteristic function on which is superimposed a Gaussian white noise process of angular velocity which is independent of walking direction. The model produces realistic walking tracks in an air-current field (Fig. 8).
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7.
1.  Physiological mapping by recording with small electrodes in the fourth root of the crayfish (Procambarus clarkii) sixth abdominal ganglion demonstrates a somatotopic segregation of afferent axons associated with mechanoreceptors on the dorsal telson surface.
2.  Degeneration of axons resulting from local lesions in the periphery yields patterns of axon distribution in the fourth root that approximately agree with the physiological results.
3.  Physiological studies of the fifth root of the sixth ganglion demonstrate a similar segregation of fibers associated with the more caudal and more medial mechanoreceptors on the dorsal telson surface.
4.  The caudal limit of the fourth root receptive field is variable; it can include receptors that normally are innervated by the most lateral fibers in the fifth root, those closest to the fourth root. Thus the fiber distributions are contiguous, and the mechanism governing their connection with appropriate interneurons is independent of the root in which they travel to reach the ganglion.
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8.
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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9.
1.  The reactions of tympanic nerve fibers ofLocusta migratoria were recorded by glass microelectrodes in the metathoracic ganglion.
2.  The units were classified by frequency-, intensity-, and directional characteristics as well as by their response pattern. The response to speciesspecific song is compared with the response to song ofEphippiger ephippiger.
3.  The physiological properties lead to a classification into three types of low-frequency neurons (characteristic frequency 3.5–4 kHz; 4kHz; 5.5–6 kHz) and one type of high-frequency neuron (12–20 kHz). This is similar to other species (Gray, 1960, Michelsen, 1971).
4.  Intensity-coding is done by sharp rising intensity characteristics and by different absolute thresholds of the units.
5.  There is a marked directional sensitivity with some differences between LF and HF units. In the low frequency range the tympanal organ seems to react as a pressure gradient receiver; for high frequencies another mechanism is discussed.
6.  No filtering of species-specific song takes place at the level of the receptor cells.
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10.
1.  Muscles of the posterior cardiac plate (pcp) and pyloric regions in the stomach of Squilla are innervated by motoneurons located in the stomatogastric ganglion (STG). The pattern of innervation of various muscles in these regions was determined using electrophysiological methods.
2.  The dilator muscles are singly or doubly innervated by the pyloric dilator neurons (PDs). The constrictor muscles are singly or doubly innervated by the pcp neuron (PCP) or the pyloric neurons (PYs). These muscles are sequentially activated by pcp-pyloric motor outputs produced by the PCP, PY, and PD. All muscles can generate an all-or-nothing spike.
3.  The constrictor muscles generate spikes followed by depolarizing afterpotentials which lead to a sustained depolarization with repetitive spikes. The PYs can entrain rhythmic spike discharges of these muscles.
4.  The spike of muscles remains unchanged by bath application of tetrodotoxin (10-7 M) to suppress neuronal impulse activities, but it is blocked by Mn2+ (10 mM).
5.  The constrictor muscle isolated from the STG displays an endogenous property of spontaneous membrane oscillation that produces a train of spikes. Brief depolarizing or hyperpolarizing stimuli can trigger or terminate an oscillatory potential, respectively, and reset the subsequent rhythm.
6.  The possible functions of myogenicity under the control of discharges of motoneurons in the pyloric constrictor neuromuscular system are discussed.
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11.
Intracellular recordings were carried out on locust flight motoneurons after hemisection of individual thoracic ganglia. With the exception of minimal surgical manipulations, the animals were intact and able to perform tethered flight. Analysis of the synaptic drive recorded in the motoneurons during flight motor activity revealed the extent to which ganglion hemisection influenced the premotor rhythm generating network.
1.  Hemisection of the mesothoracic ganglion (Fig. 2) as well as hemisection of both the mesothoracic and the prothoracic ganglia (Fig. 3) had no significant effects on the pattern of synaptic input to the flight motoneurons. Thus the rhythm generating premotor network does not depend on commissural information transfer in the mesothoracic and the prothoracic ganglia. This conclusion was supported by experiments in which more extensive surgical isolations of thoracic ganglia were carried out (Fig. 5).
2.  Removal of input from wing receptors (deafferentation) in addition to hemisection of the mesothoracic ganglion (Fig. 4) resulted in rhythmic and coordinated oscillations of the motoneuron membrane potential which were indistinguishable from those observed in deafferented animals with all ganglia intact.
3.  Hemisection of the metathoracic ganglion had more pronounced effects on the patterns of synaptic drive to the flight motoneurons and their spike discharge. Rhythmic activity which was often subthreshold could, however, still be recorded following a metathoracic split (Fig. 6).
4.  No rhythmic synaptic input was observed after hemisection of both mesothoracic and metathoracic ganglia (Fig. 7).
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12.
1.  We used laser vibrometry and free field sound stimulation to study the frequency responses of the eardrum and the lateral body wall of awake male Eleutherodactylus coqui.
2.  The eardrum snowed one of two distinct frequency responses depending on whether the glottis was open (GO response) or closed (GC response) during the measurement.
3.  The lateral body wall vibrated with a maximum amplitude close to that of the eardrum and in the same frequency range.
4.  Covering the frog's body wall with vaseline reduced the vibration amplitude of the GC response by up to 15 dB.
5.  When a closed sound delivery system was used to stimulate a local area of the body wall the eardrum also showed one of two types of responses.
6.  These results suggest that sound is transmitted via the lung cavity to the internal surface of the eardrum. This lung input has a significant influence on the vibrations of the eardrum even when the glottis is closed.
7.  The vibration amplitude of the eardrum changed with the angle of sound incidence. The directionality was most pronounced in a narrow frequency range between the two main frequencies of the conspecific advertisement call.
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13.
1.  Coordinated movements of the wings during flight in the locust result from coordinated activity of flight neurons in the thoracic ganglia. Many flight interneurons and motoneurons fire synchronous bursts of action potentials during the expression of the flight motor pattern. The mechanisms which underlie this synchronous firing were investigated in a deafferented preparation of Locusta migratoria.
2.  Simultaneous intracellular recordings were taken from flight neurons in the mesothoracic ganglion using glass microelectrodes filled with fluorescent dye.
3.  Three levels of synchronous activity between synergistic motoneurons and between the right and left partners of bilaterally symmetrical pairs of interneurons were observed: bursting which was loosely in phase but which showed little correlation between the temporal parameters of individual bursts in the two neurons; bursting which showed synchrony of the beginning and end of bursts; and bursts which showed highly synchronous spike-for-spike activity.
4.  Direct interactions between the neurons had little or no part to play in maintaining any of the levels of synchrony, even in instances of very close synchrony (spikes in different neurons occurring within 1 ms of each other). Highly synchronous firing was a consequence of common synaptic input impinging on neurons with similar morphological and physiological properties.
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14.
1.  Certain species of tiger moths emit clicks when stimulated by bat-like sounds. These clicks are generated by modified thoracic episterna (tymbals) (Fig. 1) and constitute a rhythmic behaviour activated by simple sensory input.
2.  Tymbal periods are indirectly related to stimulus intensity and periods (Fig. 3). Moths initiate sounds with the tymbal opposite to the stimulated ear and once a sequence commences it continues in an undisrupted fashion.
3.  The tymbal is innervated by a pleural branch (IIIN2a) of the metathoracic leg nerve, a similar anatomy to that in the unmodified episterna of silent moths (Fig. 5). Backfills of the IIIN2a in Cycnia tenera reveal sensory fibres and a cluster of 5–9 motor neurons with densely overlying dendritic fields (Fig. 6).
4.  Extracellular recordings of the IIIN2a reveal a large impulse preceding each tymbal sound (Fig. 7). I suggest that this impulse results from the synchronous firing of 2–3 motor neurons and is the motor output of the tymbal central pattern generator (CPG). The spikes alternate (Figs. 9, 10) and are bilaterally co-related (Fig. 11) but with an phase asymmetry of 2–3 ms (Fig. 12).
5.  Normal motor output continues in the absence of tymbal sounds (Fig. 13) and when all nerve-tymbal connections are severed (Fig. 14, Table 1) therefore this CPG operates independent of sensory feedback. A model is proposed for the tymbal circuitry based upon the present data and the auditory organization of related noctuid moths (Fig. 15). I propose that the tymbal response in modern arctiids evolved from either flight or walking CPGs and that preadaptive circuitry ancestral to tymbal movements still exists in modern silent Lepidoptera.
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15.
Thiolutin was found to inhibit the utilization of glucose and other growth substrates in Escherichia coli. The inhibition was detected by a sharp drop of the respiration rate after addition of the antibiotic. The actual function affected was allocated to the cytoplasmic membrane of the bacterial cells by the following evidence:
–  - spheroplasts were affected like intact cells,
–  - individual reactions of either the electron transport chain or the glycolytic pathway were not inhibited,
–  - glucose consumption in the culture stopped and the cells accumulated guanosine tetraphosphate as under starvation conditions,
–  - activation of the cell's apo-glucose dehydrogenase restored respiration via bypassing the glucose phosphotransferase system.
It was concluded that the transport of certain substrates across the membrane was inhibited.  相似文献   

16.
Twelve of the main European LCA software packages currently available are examined wirh the aim of establishing which are the most appropriate for LCAs on industrial processes. The packages performances are assessed in terms of
–  • Volume of Data
–  • WindowsTM environment
–  • Network Capabilities
–  • Impact Assessment
–  • Graphical representation of the inventory results
–  • Sensitivity analysis
–  • Units
–  • Cost
–  • User Support
–  • Flow Diagrams
–  • Burdens allocation
–  • Transparency of data
–  • Input & output parameters
–  • Demo version
–  • Quality of data
The review concludes with a Specification Table which summarises the facilities available on each software package. The general conclusion from this study is that for industrially based LCAs, there are four packages which may offer advantages over the rest. These are The Boustead Model, The Ecobilan Group’s TEAM™, PEMS 3.0 and SimaPro 3.1.  相似文献   

17.
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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18.
1.  The wasp Ampulex compressa hunts cockroaches as food for her offspring. Stung cockroaches show little spontaneous movement although they are able to move. Wind stimuli to the cerci, which normally produce escape responses, are no longer effective in stung cockroaches. In the present paper, we have searched for neural correlates responsible for the impairment of the escape behavior by the venom.
2.  In control cockroaches, a typical motor response in the coxal depressor muscle to wind or tactile stimuli consists of an initial burst of the fast and slow depressor motoneurons followed by rhythmic discharges. In stung cockroaches, both stimuli evoke only a burst in the slow but no discharge activity in the fast depressor neuron. Intracellular recordings from the fast depressor motoneuron in stung cockroaches demonstrate that it still receives synaptic input, though subthreshold, from thoracic interneurons associated with the wind mediated escape circuitry. Discharge activity of the slow motoneuron lacks the rhythmic bursting pattern characteristic for slow walking in control animals.
3.  Yet, the venom affects neither the response of descending mechanosensitive giant interneurons to tactile stimuli nor the response of the abdominal giant interneurons to wind stimuli, both of which are known to excite the thoracic interneurons. The venom has also no effect on neuromuscular signal transmission.
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19.
1.  Two campaniform sensilla (CS) on the proximal tibia of a hindleg monitor strains set up when a locust prepares to kick, or when a resistance is met during locomotion. The connections made by these afferents with interneurones and leg motor neurones have been investigated and correlated with their role in locomotion.
2.  When flexor and extensor tibiae muscles cocontract before a kick afferents from both campaniform sensilla spike at frequencies up to 650 Hz. They do not spike when the tibia is extended actively or passively unless it encounters a resistance. The fast extensor tibiae motor neurone (FETi) then produces a sequence of spikes in a thrusting response with feedback from the CS afferents maintaining the excitation. Destroying the two campaniform sensilla abolishes the re-excitation of FETi.
3.  Mechanical stimulation of a single sensillum excites extensor and flexor tibiae motor neurones. The single afferent from either CS evokes EPSPs in the fast extensor motor neurone and in certain fast flexor tibiae motor neurones which follow each sensory spike with a central latency of 1.6 ms that suggests direct connections. The input from one receptor is powerful enough to evoke spikes in FETi. The slow extensor motor neurone does not receive a direct input, although it is excited and slow flexor tibiae motor neurones are unaffected.
4.  Some nonspiking interneurones receive direct connections from both afferents in parallel with the motor neurones. One of these interneurones excites the slow and fast extensor tibiae motor neurones probably by disinhibition. Hyperpolarization of this interneurone abolishes the excitatory effect of the CS on the slow extensor motor neurone and reduces the excitation of the fast. The disinhibitory pathway may involve a second nonspiking interneurone with direct inhibitory connections to both extensor motor neurones. Other nonspiking interneurones distribute the effects of the CS afferents to motor neurones of other joints.
5.  The branches of the afferents from the campaniform sensilla and those of the motor neurones and interneurones in which they evoke EPSPs project to the same regions of neuropil in the metathoracic ganglion.
6.  The pathways described will ensure that more force is generated by the extensor muscle when the tibia is extended against a resistance. The excitatory feedback to the extensor and flexor motor neurones will also contribute to their co-contraction when generating the force necessary for a kick.
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20.
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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