Activation of Embryonic Red and White Muscle Fibers During Fictive Swimming in the Developing Zebrafish

2002 ◽  
Vol 87 (3) ◽  
pp. 1244-1251 ◽  
Author(s):  
Robert R. Buss ◽  
Pierre Drapeau

Sub-threshold, motoneuron-evoked synaptic activity was observed in zebrafish embryonic red (ER) and white (EW) muscle fibers paralyzed with a dose of d-tubocurarine insufficient to abolish synaptic activity to determine whether muscle activation was coordinated to produce the undulating body movements required for locomotion. Paired whole-cell recordings revealed a synaptic drive that alternated between ipsilateral and contralateral myotomes and exhibited a rostral-caudal delay in timing appropriate for swimming. Both ER and EW muscle were activated during fictive swimming. However, at the fastest fictive swimming rates, ER fibers were de-recruited, whereas they could be active in isolation of EW fibers at the slowest fictive swimming rates. Prior to hatching, fictive swimming was preceded by a lower frequency, more robust and rhythmic synaptic drive resembling the “coiling” behavior of fish embryos. The motor activity observed in paralyzed zebrafish closely resembled the swimming and coiling behaviors observed in these developing fishes. At the early developmental stages examined in this study, myotomal muscle recruitment and coordination were similar to that observed in adult fishes during swimming. Our results indicate that the patterned activation of myotomal muscle is set from the onset of development.

2000 ◽  
Vol 84 (3) ◽  
pp. 1545-1557 ◽  
Author(s):  
Robert R. Buss ◽  
Pierre Drapeau

The zebrafish is a model organism for studies of vertebrate muscle differentiation and development. However, an understanding of fish muscle physiology during this period is limited. We examined the membrane, contractile, electrical coupling, and synaptic properties of embryonic red (ER) and white (EW) muscle fibers in developing zebrafish from 1 to 5 days postfertilization. Resting membrane potentials were −73 mV in 1 day ER and −78 mV in 1 day EW muscle and depolarized 17 and 7 mV, respectively, by 5 days. Neither fiber type exhibited action potentials. Current-voltage relationships were linear in EW fibers and day 1 ER fibers but were outwardly rectifying in some ER fibers at 3 to 5 days. Both ER and EW fibers were contractile at all ages examined (1 to 5 days) and could follow trains of electrical stimulation of up to 30 Hz without fatiguing for up to 5 min. Synaptic activity consisting of miniature endplate potentials (mEPPs) was observed at the earliest ages examined (1.2–1.4 days) in both ER and EW fibers. Synaptic activity increased in frequency, and mEPP amplitudes were larger by 5 days. Miniature EPP rise times and half-widths decreased in ER fibers by 5 days, while EW fiber mEPPs showed fast kinetics as early as 1.2–1.4 days. ER and EW muscle fibers showed extensive dye coupling but not heterologous (red-white) coupling. Dye coupling decreased by 3 days yet remained at 5 days. Somites were electrically coupling, and this allowed filtered synaptic potentials to spread from myotome to myotome. It is concluded that at early developmental stages the physiological properties of ER and EW muscle are similar but not identical and are optimized to the patterns of swimming observed at these stages.


Author(s):  
J. P. Revel

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.


2017 ◽  
Vol 186 (1) ◽  
pp. 103-112
Author(s):  
Lukáš Laibl ◽  
Oldřich Fatka

This contribution briefly summarizes the history of research, modes of preservation and stratigraphic distribution of 51 trilobite and five agnostid taxa from the Barrandian area, for which the early developmental stages have been described.


2021 ◽  
Vol 22 (3) ◽  
pp. 1210
Author(s):  
Krzysztof Formicki ◽  
Agata Korzelecka-Orkisz ◽  
Adam Tański

The number of sources of anthropogenic magnetic and electromagnetic fields generated by various underwater facilities, industrial equipment, and transferring devices in aquatic environment is increasing. These have an effect on an array of fish life processes, but especially the early developmental stages. The magnitude of these effects depends on field strength and time of exposure and is species-specific. We review studies on the effect of magnetic fields on the course of embryogenesis, with special reference to survival, the size of the embryos, embryonic motor function, changes in pigment cells, respiration hatching, and directional reactions. We also describe the effect of magnetic fields on sperm motility and egg activation. Magnetic fields can exert positive effects, as in the case of the considerable extension of sperm capability of activation, or have a negative influence in the form of a disturbance in heart rate or developmental instability in inner ear organs.


2021 ◽  
Vol 22 (4) ◽  
pp. 1854
Author(s):  
Tabinda Sidrat ◽  
Zia-Ur Rehman ◽  
Myeong-Don Joo ◽  
Kyeong-Lim Lee ◽  
Il-Keun Kong

The Wnt/β-catenin signaling pathway plays a crucial role in early embryonic development. Wnt/β-catenin signaling is a major regulator of cell proliferation and keeps embryonic stem cells (ESCs) in the pluripotent state. Dysregulation of Wnt signaling in the early developmental stages causes several hereditary diseases that lead to embryonic abnormalities. Several other signaling molecules are directly or indirectly activated in response to Wnt/β-catenin stimulation. The crosstalk of these signaling factors either synergizes or opposes the transcriptional activation of β-catenin/Tcf4-mediated target gene expression. Recently, the crosstalk between the peroxisome proliferator-activated receptor delta (PPARδ), which belongs to the steroid superfamily, and Wnt/β-catenin signaling has been reported to take place during several aspects of embryonic development. However, numerous questions need to be answered regarding the function and regulation of PPARδ in coordination with the Wnt/β-catenin pathway. Here, we have summarized the functional activation of the PPARδ in co-ordination with the Wnt/β-catenin pathway during the regulation of several aspects of embryonic development, stem cell regulation and maintenance, as well as during the progression of several metabolic disorders.


Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 638
Author(s):  
Monika Mazur ◽  
Daria Wojciechowska ◽  
Ewa Sitkiewicz ◽  
Agata Malinowska ◽  
Bianka Świderska ◽  
...  

The slime mold Dictyostelium discoideum’s life cycle includes different unicellular and multicellular stages that provide a convenient model for research concerning intracellular and intercellular mechanisms influencing mitochondria’s structure and function. We aim to determine the differences between the mitochondria isolated from the slime mold regarding its early developmental stages induced by starvation, namely the unicellular (U), aggregation (A) and streams (S) stages, at the bioenergetic and proteome levels. We measured the oxygen consumption of intact cells using the Clarke electrode and observed a distinct decrease in mitochondrial coupling capacity for stage S cells and a decrease in mitochondrial coupling efficiency for stage A and S cells. We also found changes in spare respiratory capacity. We performed a wide comparative proteomic study. During the transition from the unicellular stage to the multicellular stage, important proteomic differences occurred in stages A and S relating to the proteins of the main mitochondrial functional groups, showing characteristic tendencies that could be associated with their ongoing adaptation to starvation following cell reprogramming during the switch to gluconeogenesis. We suggest that the main mitochondrial processes are downregulated during the early developmental stages, although this needs to be verified by extending analogous studies to the next slime mold life cycle stages.


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