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E E Ball

Publications and source records attributed to E E Ball.

At least 37 records · Page 2Linked to original sources
PubMed1992

Changing role of even-skipped during the evolution of insect pattern formation.

The development of Drosophila is typical of the so-called long germband mode of insect development, in which the pattern of segments is established by the end of the blastoderm stage. Short germband insects, such as the grasshopper Schistocerca americana, by contrast, generate all or most of their metameric pattern after the blastoderm stage by the sequential addition of segments during caudal elongation. This difference is discernible at the molecular level in the pattern of initiation of the segment polarity gene engrailed, and the homeotic gene abdominal-A (ref. 5). For example, in both types of insects, engrailed is expressed by the highly conserved germband stage in a pattern of regularly spaced stripes, one stripe per segment. In Drosophila, the complete pattern is visible by the end of the blastoderm stage, although engrailed appears initially in alternate segments in a pair-rule pattern that reflects its known control by pair-rule genes such as even-skipped. In contrast, in the grasshopper, the engrailed stripes appear one at a time after the blastoderm stage as the embryo elongates. To address the molecular basis for this difference, we have cloned the grasshopper homologue of the Drosophila pair-rule gene even-skipped and show that it does not serve a pair-rule function in early development, although it does have a similar function in both insects during neurogenesis later in development.

Amino Acid Sequence↗
PubMed1992

Position-specific expression of the annulin protein during grasshopper embryogenesis.

Annulin, named for its annular expression in developing limb buds, is a approximately 100 kDa membrane-associated protein that is expressed in a complex and changing pattern during grasshopper embryogenesis. Its expression is dynamic along the developing midline and in the mesoderm, transient in neuroepithelial sheath cells around mitotic neuroblasts, and position-specific in circumferential stripes in each limb bud segment. Annulin expression begins along the midline of the embryo at the onset of gastrulation. Mesoderm cells express the protein as they migrate away from the midline as do new cells that come to lie at the midline. During neurogenesis, annulin expression disappears from many midline cells until only a specific subset of midline glial cells expresses high levels of the protein. Starting at the beginning of neurogenesis, sheath cells express annulin in correlation with the mitotic activity of the neuroblasts they surround.

Animals↗
PubMed1990

Embryonic development of the innervation of the locust extensor tibiae muscle by identified neurons: formation and elimination of inappropriate axon branches.

Intracellular dye fills have been used to reveal the pattern of embryonic growth of each of the four neurons which innervate the extensor tibiae muscle (ETi) of the hind leg of the locust. The growth cone of the slow extensor tibiae motoneuron (SETi), the first of the four neurons to leave the central nervous system, pioneers nerve 3 (N3). The fast extensor motoneuron (FETi), the next neuron to grow out, follows earlier outgrowing motoneurons into the periphery in nerve 5 (N5) and then rejoins SETi in N3. As it transfers from N5 to N3, it is transiently dye-coupled to the Tr1 pioneer neuron which spans the gap between the two nerves. It then follows SETi onto the ETi muscle in the femur. The common inhibitory neuron and the dorsal unpaired median neuron (DUMETi) follow SETi and FETi in nerves 3B2 and 5B1, respectively. SETi's growth cone requires almost twice as long to reach ETi as those of the three later motoneurons, all of which follow preexisting neural pathways. At least three of the four developing motoneurons form one or more axon branches not found in the adult. These branches may occur (1) at segmental boundaries; (2) where the nerve, which the growth cone is following, itself branches or the growth cone encounters another nerve; or (3) when the axon continues to grow beyond its target muscle. These findings contrast with the apparent absence of inappropriate axon branches in another developing locust neuromuscular system and during the innervation of zebrafish myotomes, but resemble in some ways the transient production of inappropriate axonal branches reported for embryonic leech motoneurons.

Animals↗
PubMed1990

Computers in health care for the 21st century.

As the world enters the last decade of the 20th Century, there is a great deal of speculation about the effect of computers on the future delivery of health care. In this article, the authors attempt to identify some of the evolving computer technologies and anticipate what effect they will have by the year 2000. Rather than listing potential accomplishments, each of the affected areas: hardware, software, health care systems and communications, are presented in an evolutionary manner so the reader can better appreciate where we have been and where we are going.

Artificial Intelligence↗
PubMed1987

Haemocytes secrete basement membrane components in embryonic locusts.

Several monoclonal antibodies raised against a glycoprotein-enriched fraction of adult muscle membranes of Locusta migratoria selectively stain particles within haemocytes and basement membrane in developing locust embryos. Haemocytes containing immunoreactive particles are found associated with areas where basement membrane is being laid down. The underlying ectoderm does not show immunoreactivity. We conclude that haemocytes contribute to basement membrane formation in embryonic locusts.

Animals↗
PubMed1985

Muscle development in the grasshopper embryo. I. Muscles, nerves, and apodemes in the metathoracic leg.

Much is known about the development of nerve pathways in the metathoracic limb bud of the grasshopper embryo. In this series of three papers, we report on the development of muscles in the same embryonic appendage. In a fourth paper (E. E. Ball, R. K. Ho, and C. S. Goodman, 1985, J. Neurosci, in press) we examine the development of specific neuromuscular connections for one of these muscles (coxal muscle 133a). In this first paper, we present an overview of the development of muscles, nerves, and apodemes (tendons). We previously reported on a class of large mesodermal cells, called muscle pioneers (MPs), that arises early in development and appears to act as a scaffold for developing muscles and guidance cue for motoneuron growth cones (R. K. Ho, E. E. Ball, and C. S. Goodman, 1983, Nature (London) 301, 66-69). We have used the I-5 monoclonal antibody (which specifically labels the MPs as well as the nerve pathways), HRP immunocytochemistry, and Normarski optics to visualize muscle, nerve, and apodeme development in the embryonic metathoracic limb bud from 27.5% (before the appearance of the MPs) to 55% (after the muscles have attained their basic adult pattern). Cell fusions, cell migration, and cell death all appear to play important roles in the development of MPs. The patterns of muscle development vary greatly, ranging from (i) single MPs for simple muscles (which in the adult have only one bundle of muscle fibers, e.g., coxal muscle 133a), to (ii) arrays of MPs for complex muscles [which in the adult have many bundles of muscle fibers each with separate sites of insertion, e.g., the extensor tibiae (ETi) and flexor tibiae (FlTi) muscles in the femur].

Animals↗
PubMed1985

Muscle development in the grasshopper embryo. II. Syncytial origin of the extensor tibiae muscle pioneers.

The extensor tibiae muscle (ETi) in the metathoracic leg of the grasshopper, which powers the jump, is among the most studied insect muscles. In contrast to many insect muscles which are simple (consisting of only a single bundle of muscle fibers), the ETi is a complex muscle which consists of an array of bundles of muscle fibers, each with a separate site of insertion on the body wall ectoderm and on the ETi apodeme ectoderm. Here we describe the embryonic development of this complex muscle. The ETi muscle develops from a single muscle pioneer (MP) which connects the initial invagination of the ETi apodeme to the wall of the femur. This MP then dramatically expands around the developing apodeme to form a large horseshoe-shaped, multinucleate cell, called the supramuscle pioneer (supra-MP); the number of nuclei in the supra-MP increases by cell fusion rather than by nuclear division. The arms of the supra-MP grow steadily longer and their outer edges begin to appear scalloped, certain areas remaining tightly apposed to the ectoderm of the wall of the leg while adjacent areas lose their adhesion and are pulled away. By about 50% of embryonic development the ETi supra-MP consists of a periodic series of bridges (cytoplasmic extensions) connecting the leg wall ectoderm with the apodeme, and linked into a giant syncytium near their inner, apodeme surface by a thin layer of cytoplasm containing hundreds of nuclei. Each bridge is surrounded by a cluster of many smaller mesoderm cells. Next the syncytium begins to divide such that by 60% the periodic bridges of the supra-MP have lost syncytial contact with each other and now themselves form an array of smaller, individual, multinucleate MPs connecting the body wall to the apodeme, each surrounded by a mass of undifferentiated mesoderm cells. This initial cycle of fusion and division is followed by a second similar cycle in which the individual mesoderm cells surrounding each MP fuse with the MP. At the same time, the MP divides into the initial bundle of smaller muscle fibers. Coincident with this division into muscle fibers is the further development of thick and thin filaments and the T-tubule system.

Animals↗
PubMed1985

Muscle development in the grasshopper embryo. III. Sequential origin of the flexor tibiae muscle pioneers.

The flexor (FlTi) and extensor (ETi) tibiae are antagonist muscles located in the femur of the metathoracic leg of the grasshopper. Both are complex, consisting of an array of bundles of muscle fibers connecting the ectoderm of the wall of the femur with their respective apodemes. In the previous paper (E. E. Ball and C. S. Goodman, 1985, Dev. Biol. 111, 399-416) we described the embryonic development of the ETi muscle, focusing in particular on its syncytial origin from a giant supramuscle pioneer which later divides into an array of individual muscle pioneers. Here we describe the embryonic development of the FlTi muscle. In contrast to the development of the ETi muscle, the array of individual muscle pioneers for the FlTi does not have a syncytial origin but rather arises by sequential recruitment from the mass of smaller, undifferentiated mesoderm cells. The FlTi MPs first appear as two cells symmetrically placed on the corners of the FlTi apodeme at around 37%. A third MP is then added between these two; this third MP later dies. Subsequent growth occurs by symmetrical addition of MPs distally along the sides of the developing apodeme and by enlargement of the individual MPs. Initially each MP contains only a single nucleus; by about 50% there are at least two to three nuclei per MP and each is surrounded by a cluster of smaller, undifferentiated mesoderm cells. Each MP develops into a bundle of muscle fibers by a cycle of fusion and division. The individual mesoderm cells surrounding each MP fuse with it starting at about 60%. At the same time, the large MP begins to divide into smaller muscle fibers.

Animals↗
PubMed1985

Development of neuromuscular specificity in the grasshopper embryo: guidance of motoneuron growth cones by muscle pioneers.

In the grasshopper embryo, neuromuscular specificity develops between individual identified motoneurons whose cell bodies are located in the central nervous system, and specific skeletal muscles in the periphery. We previously reported on a class of large mesodermal cells, called muscle pioneers (MPs), that arise early in development (Ho, R. K., E. E. Ball, and C. S. Goodman (1983) Nature 301: 66-69). We suggested that the MPs might be involved in orchestrating the coordinated development of nerve and muscle. In this paper, we describe the development of the MP for coxal muscle 133a in the metathoracic limb bud, and its innervation by two excitatory motoneurons (fast, Df, and slow, Ds). Although many motoneuron growth cones extend out of nerve 5 and quite likely come in contact with the 133a MP between 35% and 45% of development, only Df and Ds display a high affinity for its surface; the other motoneurons innervate more distal leg muscles. When the 133a MP is ablated before arrival of motoneurons in the limb bud, the Df growth cone extends past the location where it normally gets off nerve 5 and continues to extend distally along the same pathway taken by its sibling motoneuron. Although there is a mass of small mesodermal cells in the area where the differentiated coxal muscle 133a normally forms, evidently it does not provide the necessary guidance cue for the Df growth cone. These results indicate the important role played by MPs in the specific guidance of motoneuron growth cones in the grasshopper embryo.

Grasshoppers↗
PubMed1983

Muscle pioneers: large mesodermal cells that erect a scaffold for developing muscles and motoneurones in grasshopper embryos.

During embryonic development, muscles differentiate in the appropriate places and motoneurone growth cones find the appropriate muscles; both events occur concurrently and with remarkable specificity. What are the cellular interactions that orchestrate this coordinated development of nerve and muscle? In the development of vertebrate skeletal muscles, motoneurone growth cones arrive in the periphery along stereotyped routes and enter the appropriately located masses of mesodermal cells usually before differentiated muscle fibres appear and before the masses cleave into separate muscles. We find that a similar sequence of events occurs in the grasshopper embryo. We are interested in how mesodermal cells become organized into the appropriate muscles and what guides motoneurone growth cones to their appropriate targets. Fortunately, in the grasshopper embryo the mesodermal cells in the periphery and motoneurones in the central nervous system (CNS) are large, accessible and in many cases individually identifiable from early in their development. We report here the discovery of a class of large mesodermal cells, which we call muscle pioneers, that arise early in development when the embryonic environment is relatively simple and distances short. By their growth and association with particular sites along the ectoderm, the muscle pioneers appear to erect a scaffold for later developing muscles and motoneurone growth cones.

Animals↗
PubMed1982

The cercal receptor system of the praying mantid, Archimantis brunneriana Sauss. I. Cercal morphology and receptor types.

The cerci of the praying mantid, Archimantis brunneriana Sauss., are paired segmented sensory organs located at the tip of the abdomen. Basally the cercal segments are slightly flattened dorso-ventrally and are fused to such a degree that it is difficult to distinguish them. Distally the segments become progressively more flattened laterally and their boundaries become more obvious. Two types of sensilla are present on the cerci, trichoid sensilla and filiform sensilla. Trichoid hairs are longest on the medial side of the cerci and toward the middle of each segment while they are more uniformly distributed on the distal segments. Filiform sensilla are found at the distal end of each segment except the last and are highly variable in appearance from short and stout to long and thin. They arise from a raised base, have a fluted shaft, and some have a pore at the tip. They are innervated by from one to five dendrites, one of which is always considerably larger than the others. Some of the dendrites continue out into the shaft of the hair. Filiform hairs have fluted shafts and are mounted in a flexible membrane within a cuticular ring in a depression. They are innervated by a single large sensory neuron, the dendrite of which passes across a flattened area on the inner wall of the lumen of the hair. The dendritic sheath forms the lining of the ecdysial canal and is therefore firmly attached to the hair. The dendrite is attached to the sheath by desmosomes distally and is penetrated by projections of the sheath more proximally. A fibrous cap surrounds the dendrite and may hold it in place relative to the hair. The cercal receptor system of Archimantis is compared to those of cockroaches and crickets.

Animals↗
PubMed1982

The cercal receptor system of the praying mantid, Archimantis brunneriana Sauss. II. Cercal nerve structure and projection and electrophysiological responses of the individual receptors.

The bilaterally paired cercal nerves of Archimantis brunneriana Sauss. leave the terminal ganglion posteriorly and then turn dorsally through muscles at the rear of the abdomen to enter the cerci, where each splits into two branches; successive branchings occur further distally in each cercus. In the distal nerve branches large axons tend to be grouped together. The cercal nerves are heavily wrapped in glial sheaths. Cobalt backfills of the cercal nerve reveal a projection which enters the ganglion at approximately 30 degrees to the midline and then turns parallel to it. Most of the projection remains ipsilateral but bundles of axons approach or cross the midline in 6-8 places. At the anterior end of the ganglion there are strong projections both laterally and medially. In the posterior half of the ganglion fibers run ventrally to surround two glomeruli and there is a dorsal projection in the anterior half of the ganglion. There is a strong projection anteriorly into the ventral nerve cord. The electrophysiological responses of single cercal receptors to pulses of wind were recorded in the cercal nerve or terminal ganglion. These receptors, presumed to innervate filiform hairs, were then filled with Lucifer Yellow. All had ipsilateral projections. Most receptors showed little adaptation to stimuli as long as 5 seconds.

Animals↗
PubMed1981

Structure of the auditory system of the weta Hemideina crassidens (blanchard, 1851) (Orthoptera, Ensifera, Gryllacridoidea, Stenopelmatidae). 1. Morphology and histology.

The morphology and histology of the tibial auditory system of the New Zealand weta, Hemideina crassidens, are described. The groups of acoustic sensilla conform closely to the subgenual organ, intermediate organ and crista acoustica of the Tettigoniidae. Each prothoracic tibia bears two thick (40-100 micrometers) tympana of approximately equal size divided into two distinct zones. The tracheae of the prothoracic legs are connected across the midline by a transverse commissure and by a chiasma between the ventral longitudinal trunks. No expanded vesicle ("vesicula acoustica") is associated with the spiracle. The anterior and posterior tracheae are divided into three distinct regions within the tibia: (1) a bulbous proximal posterior inflated chamber, (2) the tympanal vesicles to which the tympana attach, and (3) an elongate distal posterior inflated chamber. The pattern of innervation in the tympanal region is similar to that of gryllids as is the central projection of the tympanal nerve. The subgenual organ, which contains ca. 50 sensilla, forms an acute angle with the wall of the leg. The intermediate organ contains ca. 19 sensilla forming an arc against the anterior wall of the leg. The crista acoustica contains ca. 50 sensilla aligned in a gelatinous matrix along the dorsal surface of the anterior tympanal vesicle. Each dendrite projects distally, then is reflected proximally and dorsally to end in a scolopale embedded in an attachment cell. The attachment cells are stellate in the proximal portion of the crista, but distally they occur as parallel lamellae. The weta ear is compared with those of other Orthoptera.

Animals↗
PubMed1981

Structure of the auditory system of the weta Hemideina crassidens (Blanchard, 1851). (Orthoptera, Ensifera, Gryllacridoidea, Stenopelmatidae). 2. Ultrastructure of the auditory sensilla.

This study of the ultrastructure of the auditory sensilla of the New Zealand weta, Hemideina crassidens, is the first such study on a member of the orthopteran Superfamily Gryllacridoidea. Ultrastructure of the auditory sensilla is similar in all of the tibial mechanosensory organs, here called subgenual organ, intermediate organ and crista acoustica by analogy with comparable structures in Tettigoniidae. Distal to each sensory soma is a dendrite containing multiple ciliary rootlets that fuse into a single ciliary root. This splits into nine root processes that pass around the outside of the proximal basal body and then rejoin at the level of the distal basal body, distal to which the dendrite has a modified ciliary structure with a circlet of nine peripheral paired tubes and rods as it passes through the proximal extracellular space. It is then enclosed by a zone of scolopale cell cytoplasm before expanding into a dilatation within the distal extracellular space. In some sensilla this space is partially occluded by electron dense material which is part of the scolopale cell. Distal to the dilatation the cilium shrinks and ends surrounded by the scolopale cap. Accessory cells consist of glia enwrapping the sensory neuron in the region of its soma, the scolopale cell surrouinding the ciliary portion of the dendrite, and the attachment cell surrounding the scolopale cell and scolopale cap and connected to them by desmosomes. The attachment cells are filled with microtubules in differing densities and orientations. Lamellae are present in the acellular matrix surrounding the attachment cells. Banded fibres, presumably of collagen, are also present in the matrix.

Animals↗
PubMed1978

Ultrastructural study of the development of the auditory tympana in the cricket Teleogryllus commodus (Walker).

The cuticle in the tympanal area of immature crickets, Teleogryllus commodus (Walker), is ultrastructurally indistinguishable from that elsewhere on the prothoracic leg. It is only in the pharate adult that changes associated with development of the tympana first appear. In pharate adults and adults the external layer of the tympana consists of a layer of electron-dense material overlying a layer where the electron-dense material is interspersed with cuticle in which the bundles of microfibrils are coarser and more loosely arranged than elsewhere in the leg. The innermost portion of the tympana consists of this same type of cuticle without the electron-dense material. Associated with the appearance of the electron-dense material in the tympana of the pharate adult is a change in the toluidine blue staining properties from blue to deep purple. The reaction of the tympana in acid and base is consistent with their being composed of chitin. There are no major deposits of resilin in the tympana. In the first few days following the imaginal ecdysis the posterior tympanum and underlying trachea come into tight apposition due to the withdrawal of the epidermal cells. The epidermal cells do not withdraw from beneath the anterior tympanum. The surrounding non-tympanal cuticle continues to thicken for several weeks with the result that in the mature adult the posterior tympanum serves as an acoustic window in the thick cuticle of the leg. The functional significance of the anterior tympanum has not been established.

Animals↗