The gene tinman is required for specification of the heart and visceral muscles in Drosophila

Development ◽  
1993 ◽  
Vol 118 (3) ◽  
pp. 719-729 ◽  
Author(s):  
R. Bodmer
Keyword(s):  
Heart Development ◽  
Body Wall ◽  
Heart Cells ◽  
Visceral Muscle ◽  
Visceral Mesoderm ◽  
Body Wall Muscles ◽  
Visceral Muscles

The homeobox-containing gene tinman (msh-2, Bodmer et al., 1990 Development 110, 661–669) is expressed in the mesoderm primordium, and this expression requires the function of the mesoderm determinant twist. Later in development, as the first mesodermal subdivisions are occurring, expression becomes limited to the visceral mesoderm and the heart. Here, I show that the function of tinman is required for visceral muscle and heart development. Embryos that are mutant for the tinman gene lack the appearance of visceral mesoderm and of heart primordia, and the fusion of the anterior and posterior endoderm is impaired. Even though tinman mutant embryos do not have a heart or visceral muscles, many of the somatic body wall muscles appear to develop although abnormally. When the tinman cDNA is ubiquitously expressed in tinman mutant embryos, via a heatshock promoter, formation of heart cells and visceral mesoderm is partially restored, tinman seems to be one of the earliest genes required for heart development and the first gene reported for which a crucial function in the early mesodermal subdivisions has been implicated.

The Ligamentary System and the Segmental Musculature of Nephtys

1960 ◽  
Vol s3-101 (54) ◽  
pp. 149-176
Author(s):  
R. B. CLARK ◽  
M. E. CLARK
Keyword(s):  
Body Wall ◽  
The Body ◽  
Power Stroke ◽  
Coelomic Fluid ◽  
Unusual Structure ◽  
Shock Absorbers ◽  
Proximal Half ◽  
Unique System ◽  
Body Wall Muscles ◽  
The Impact

Nephtys lacks circular body-wall muscles. The chief antagonists of the longitudinal muscles are the dorso-ventral muscles of the intersegmental body-wall. The worm is restrained from widening when either set of muscles contracts by the combined influence of the ligaments, some of the extrinsic parapodial muscles, and possibly, to a limited extent, by the septal muscles. Although the septa are incomplete, they can and do form a barrier to the transmission of coelomic fluid from one segment to the next under certain conditions, particularly during eversion of the proboscis. Swimming is by undulatory movements of the body but the distal part of the parapodia execute a power-stroke produced chiefly by the contraction of the acicular muscles. It is suspected that the extrinsic parapodial muscles, all of which are inserted in the proximal half of the parapodium, serve to anchor the parapodial wall at the insertion of the acicular muscles and help to provide a rigid point of insertion for them. Burrowing is a cyclical process involving the violent eversion of the proboscis which makes a cavity in the sand. The worm is prevented from slipping backwards by the grip the widest segments have on the sides of the burrow. The proboscis is retracted and the worm crawls forward into the cavity it has made. The cycle is then repeated. Nephtys possesses a unique system of elastic ligaments of unusual structure. The anatomy of the system is described. The function of the ligaments appears to be to restrain the body-wall and parapodia from unnecessary and disadvantageous dilatations during changes of body-shape, and to serve as shock-absorbers against the high, transient, fluid pressures in the coelom, which are thought to accompany the impact of the proboscis against the sand when the worm is burrowing. From what is known of its habits, Nephtys is likely to undertake more burrowing than most other polychaetes.

scholarly journals Segmental differences in firing properties and potassium currents in Drosophila larval motoneurons

2012 ◽  
Vol 107 (5) ◽  
pp. 1356-1365 ◽  
Author(s):  
Subhashini Srinivasan ◽  
Kimberley Lance ◽  
Richard B. Levine
Keyword(s):  
Patch Clamp ◽  
Abdominal Segment ◽  
Body Wall ◽  
Potassium Currents ◽  
Whole Cell Patch Clamp ◽  
Voltage Dependent ◽  
Body Wall Muscles ◽  
Motoneuron Activity ◽  
Firing Properties ◽  
Thoracic And Abdominal

Potassium currents play key roles in regulating motoneuron activity, including functional specializations that are important for locomotion. The thoracic and abdominal segments in the Drosophila larval ganglion have repeated arrays of motoneurons that innervate body-wall muscles used for peristaltic movements during crawling. Although abdominal motoneurons and their muscle targets have been studied in detail, owing, in part, to their involvement in locomotion, little is known about the cellular properties of motoneurons in thoracic segments. The goal of this study was to compare firing properties among thoracic motoneurons and the potassium currents that influence them. Whole-cell, patch-clamp recordings performed from motoneurons in two thoracic and one abdominal segment revealed both transient and sustained voltage-activated K+ currents, each with Ca++-sensitive and Ca++-insensitive [A-type, voltage-dependent transient K+ current (IAv)] components. Segmental differences in the expression of voltage-activated K+ currents were observed. In addition, we demonstrate that Shal contributes to IAv currents in the motoneurons of the first thoracic segment.

Electrophysiology of Acanthocephalan Body Wall Muscles

1979 ◽  
Vol 82 (1) ◽  
pp. 273-280
Author(s):  
B. S. WONG ◽  
DONALD M. MILLER ◽  
T. T. DUNAGAN
Keyword(s):  
Light Microscopy ◽  
Intracellular Recording ◽  
Body Wall ◽  
Membrane Potentials ◽  
The Body ◽  
Spontaneous Potential ◽  
Body Wall Muscles ◽  
Macracanthorhynchus Hirudinaceus ◽  
Anterior Posterior

Body wall muscles of an acanthocephalan Macracanthorhynchus hirudinaceus were studied by means of scanning and light microscopy and intracellular recording of potentials. Three types of spontaneous potential changes were found: larger (L) potentials which usually exhibited overshoot and were as large as 65 mV; smaller symmetric (A) potentials approximately 15 mV in amplitude; and even smaller asymmetric (S) potentials which sometimes reached 10 mV. The potentials recorded depended upon the position of the electrode in the anterior-posterior, as well as the medialateral, axis. Tetrodotoxin eliminated L but not S potentials. Ouabain lengthened the time for depolarization of L potentials and depolarized the membrane potentials. It is suggested that the rete system activates the body wall muscles in Acanthocephala.

Positioning and maintenance of embryonic body wall muscle attachments in C. elegans requires the mup-1 gene

Development ◽  
1991 ◽  
Vol 111 (3) ◽  
pp. 667-681 ◽  
Author(s):  
P.Y. Goh ◽  
T. Bogaert
Keyword(s):  
Extracellular Matrix ◽  
Body Wall ◽  
Early Stage ◽  
Muscle Growth ◽  
The Body ◽  
Body Wall Muscle ◽  
C Elegans ◽  
Extracellular Matrix Molecule ◽  
Extracellular Matrix Components ◽  
Body Wall Muscles

As part of a general study of genes specifying a pattern of muscle attachments, we identified and genetically characterised mutants in the mup-1 gene. The body wall muscles of early stage mup-1 embryos have a wild-type myofilament pattern but may extend ectopic processes. Later in embryogenesis, some body wall muscles detach from the hypodermis. Genetic analysis suggests that mup-1 has both a maternal and a zygotic component and is not required for postembryonic muscle growth and attachment. mup-1 mutants are suppressed by mutations in several genes that encode extracellular matrix components. We propose that mup-1 may encode a cell surface/extracellular matrix molecule required both for the positioning of body wall muscle attachments in early embryogenesis and the subsequent maintenance of these attachments to the hypodermis until after cuticle synthesis.

Coordination of locomotor and cardiorespiratory networks of Lymnaea stagnalis by a pair of identified interneurones

1991 ◽  
Vol 158 (1) ◽  
pp. 37-62 ◽  
Author(s):  
N. I. Syed ◽  
W. Winlow
Keyword(s):  
Body Wall ◽  
Lymnaea Stagnalis ◽  
The Body ◽  
Whole Body ◽  
Pond Snail ◽  
Selective Ablation ◽  
The Central Nervous System ◽  
Body Wall Muscles ◽  
Bilateral Pair ◽  
Left And Right

1. The morphology and electrophysiology of a newly identified bilateral pair of interneurones in the central nervous system of the pulmonate pond snail Lymnaea stagnalis is described. 2. These interneurones, identified as left and right pedal dorsal 11 (L/RPeD11), are electrically coupled to each other as well as to a large number of foot and body wall motoneurones, forming a fast-acting neural network which coordinates the activities of foot and body wall muscles. 3. The left and right sides of the body wall of Lymnaea are innervated by left and right cerebral A cluster neurones. Although these motoneurones have only ipsilateral projections, they are indirectly electrically coupled to their contralateral homologues via their connections with L/RPeD11. Similarly, the activities of left and right pedal G cluster neurones, which are known to be involved in locomotion, are also coordinated by L/RPeD11. 4. Selective ablation of both neurones PeD11 results in the loss of coordination between the bilateral cerebral A clusters. 5. Interneurones L/RPeD11 are multifunctional. In addition to coordinating motoneuronal activity, they make chemical excitatory connections with heart motoneurones. They also synapse upon respiratory motoneurones, hyperpolarizing those involved in pneumostome opening (expiration) and depolarizing those involved in pneumostome closure (inspiration). 6. An identified respiratory interneurone involved in pneumostome closure (visceral dorsal 4) inhibits L/RPeD11 together with all their electrically coupled follower cells. 7. Both L/RPeD11 have strong excitatory effects on another pair of electrically coupled neurones, visceral dorsal 1 and right parietal dorsal 2, which have previously been shown to be sensitive to changes in the partial pressure of environmental oxygen (PO2). 8. Although L/RPeD11 participate in whole-body withdrawal responses, electrical stimulation applied directly to these neurones was not sufficient to induce this behaviour.

Characterization of a novel subset of cardiac cells and their progenitors in the Drosophila embryo

Development ◽  
2000 ◽  
Vol 127 (22) ◽  
pp. 4959-4969 ◽  
Author(s):  
E.J. Ward ◽  
J.B. Skeath
Keyword(s):  
Heart Development ◽  
Cell Types ◽  
Cardiac Cells ◽  
Lineage Tracing ◽  
Drosophila Embryo ◽  
Heart Cells ◽  
Pericardial Cells ◽  
Asymmetric Divisions ◽  
Genetic Mechanisms

The Drosophila heart is a simple organ composed of two major cell types: cardioblasts, which form the simple contractile tube of the heart, and pericardial cells, which flank the cardioblasts. A complete understanding of Drosophila heart development requires the identification of all cell types that comprise the heart and the elucidation of the cellular and genetic mechanisms that regulate the development of these cells. Here, we report the identification of a new population of heart cells: the Odd skipped-positive pericardial cells (Odd-pericardial cells). We have used descriptive, lineage tracing and genetic assays to clarify the cellular and genetic mechanisms that control the development of Odd-pericardial cells. Odd skipped marks a population of four pericardial cells per hemisegment that are distinct from previously identified heart cells. We demonstrate that within a hemisegment, Odd-pericardial cells develop from three heart progenitors and that these heart progenitors arise in multiple anteroposterior locations within the dorsal mesoderm. Two of these progenitors divide asymmetrically such that each produces a two-cell mixed-lineage clone of one Odd-pericardial cell and one cardioblast. The third progenitor divides symmetrically to produce two Odd-pericardial cells. All remaining cardioblasts in a hemisegment arise from two cardioblast progenitors each of which produces two cardioblasts. Furthermore, we demonstrate that numb and sanpodo mediate the asymmetric divisions of the two mixed-lineage heart progenitors noted above.

scholarly journals Dstac Regulates Excitation-Contraction Coupling in Drosophila Body Wall Muscles

2020 ◽  
Vol 11 ◽  
Author(s):  
I-Uen Hsu ◽  
Jeremy W. Linsley ◽  
Lilly E. Reid ◽  
Richard I. Hume ◽  
Ari Leflein ◽  
...  
Keyword(s):  
Body Wall ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Body Wall Muscles
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