Zebrafish Danio rerio trunk muscle structure and growth from a spatial transcriptomics perspective

Compared to mammals, some fish exhibit indeterminate growth characteristics, meaning they can continue growing throughout their lives. Zebrafish trunk skeletal muscle can in general be classified into slow, intermediate, and fast based on morphological and physiological characteristics. After hatching, hyperplasia can be observed in the muscles of juvenile zebrafish, and with growth, hyperplasia in the fast muscles gradually decreases until it stagnates, after which fast muscle development relies on hypertrophy. In slow muscle, hyperplasia continues throughout life. Teleost muscle structure and growth has been described mainly by morphological and physiological features based on the expression of a limited number of proteins, transcripts, and metabolites. The details of mechanism remain unclear. Visium Spatial Gene Expression solution was used in this study. On the adult slide, 10 clusters were obtained based on whole gene expression similarities. The spatial expression of myosin heave chains, myosin light chains and myosin-binding proteins was investigated. GO enrichment analysis was also performed on different muscle regions of aged zebrafish. Dorsal and ventral slow muscles share the same processes such as myofibril assembly and muscle tissue development. On the larvae slide, 3 clusters were obtained, GO enrichment analysis suggest active muscle formation in zebrafish larvae.

The Developmental Phases of Zebrafish Myogenesis

The development and growth of vertebrate axial muscle have been studied for decades at both the descriptive and molecular level. The zebrafish has provided an attractive model system for investigating both muscle patterning and growth due to its simple axial musculature with spatially separated fibre types, which contrasts to complex muscle groups often deployed in amniotes. In recent years, new findings have reshaped previous concepts that define how final teleost muscle form is established and maintained. Here, we summarise recent findings in zebrafish embryonic myogenesis with a focus on fibre type specification, followed by an examination of the molecular mechanisms that control muscle growth with emphasis on the role of the dermomyotome-like external cell layer. We also consider these data sets in a comparative context to gain insight into the evolution of axial myogenic patterning systems within the vertebrate lineage.

Heavy Metal Concentrations in the Muscle Tissue of 12 Species of Teleost from Cockburn Sound, Western Australia

The wet and dry weight concentrations of Cd, Zn, Cu, Pb, Fe, Mn, Ni, Cr and Co have been measured in muscle tissue taken from 12 species of teleost caught in Cockburn Sound. The maximum concentration of each of the metals found in the fish was well below the values given in the National Health and Medical Research Council Standards and the Western Australian Food and Drug Regulations. Considering the rate at which metals are known to be discharged into the Sound the low concentrations found in fish flesh contrast with the appreciable rate at which metals are discharged and accumulate in certain regions of the Sound. Furthermore, the metal concentrations in fish flesh are many times lower than in invertebrates such as the mussel, Mytilus edulis. It is suggested that the low levels in fish flesh reflect both the relatively low rate at which heavy metals are accumulated by teleost muscle and also the movement pattern of fish within the polluted and relatively unpolluted regions of the Sound, and between the Sound and the Indian Ocean.

The Changes in Blood Glucose in Pleuronectes Platessa Following Capture From The Wild: A Stress Reaction

Changes in blood glucose levels in teleosts have been reviewed by a number of workers. Epple (1969) considered the regulation of glucose by the insulin of the fish pancreatic islet tissue, Nakano & Tomlinson (1967) examined the regulation of glucose by the catecholamines, Black, Robertson & Parker (1961) considered glucose in carbohydrate metabolism of teleost muscle, while knowledge of regulation of blood glucose in Chondrichthyans has recently been extended and reviewed by Patent (1968, 1970). The investigation of blood glucose levels and their control mechanisms dealt with in this paper forms part of a broader study of the changes that occur when fish are caught from the wild and placed in aquaria (Wardle, 1968, 1971, and unpublished). In this study, capture is considered as a stimulus imposed on the wild fish, which initiates a series of physiological changes that can be measured as the fish adapts to the aquarium.