Editorial            259      Fish myology
                                    E Carpené, and G Isani     [Full text pdf 7.59Kb]
 

Articles            261      Axial muscle development in fish
                                   G te Kronnie     [Full text pdf 94.5Kb]

                       269      Expression of myofibrillar proteins and parvalbumin isoforms in white muscle of the
                                   developing turbot Scophthalmus maximus (Pisces, Pleuronectiformes)
                                   B Focant, S Collin, P Vandewalle, and F Huriaux    [Full text pdf 197Kb]

                       279      Post-hatching development of motor innervation of lateral muscle in the seabream
                                   Sparus aurata
                                   P Berardinelli, G Radaelli, A Rowlerson, PA Scapolo, F Mascarello, and A Veggetti     [Full text pdf 161Kb]

                       285      Biochemical changes in gilthead sea-bream white muscle during post-larval growth
                                   G Isani, G Andreani, M Monari, L Dalla Libera, and E Carpenè   [Full text pdf 387Kb]

                       291      Family and population differences in muscle fibre recruitment in farmed Atlantic salmon
                                   (Salmo salar)
                                   IA Johnston, S Manthri, B Robertson, P Campbell, D Mitchell, and R Alderson   [Full text pdf 120Kb]
 

                       297      Endurance exercise training affects fast white axial muscle in the Cyprinid species
                                   Chalcalburnus chalcoides mento (Agassiz, 1832), Cyprinidae, teleostei
                                   AM Sänger, and U Pötscher     [Full text pdf 551Kb]
 
 

Fish Myology

There is an ample literature dealing with function and structure of fish muscle. A wide range of approaches are used by different scientists to improve knowledge in this important biological field for pure and applied science. In the present hot Basic and Applied Myology issue on Fish Myology, only a small part of this wide subject has been covered. In particular some topics have been included e.g.: myosin structure, expression of myofibrillar proteins and parvalbumin, effect of endurance exercise on fast muscle, motor innervation of lateral muscle, relationship between muscle growth and flesh quality.

Preparing this issue, we should not forget to mention some pioneers of fish myosin biochemistry: J.J. Connell (Aberdeen), G. Hamoir (Liege) who we met during international meetings or research exchanges. In particular we would like to mention Alba Veggetti, our professor of histochemistry and anatomy, who organized the Italian Group on fish muscle. We also have to thank the CNR Unit for Muscle Biology and Physiopathology in Padova, especially Luciano Dalla Libera who is an invaluable source of help and support, even at short notice. One of the Guest Editors was used to live close to a wonderful river (the Sile) containing many kinds of fish from grayling at its source to grey mullet at the estuary. Hours and days were spent with parental encouragement observing these aquatic vertebrates in their natural environment, and occasionally taking some to make a good inexpensive meal. This formative experience was probably what convinced the editors that behind the macroscopic diversity of the different fish there was something much more fascinating: small and big proteins, red and white fibres, special vessels and nerves. Whereas we now know a lot about the anatomy and behaviour of these fish, the richness of the molecular world, no doubt, still contains many surprises for the future.

Last but not least, we would like to thank all the authors who have contributed to this volume, and hope that readers will be encouraged to contribute to this field in the future.

Emilio Carpené, Gloria Isani, Guest Editors

Department of Biochemistry

Veterinary Section

University of Bologna

Italy

Axial Muscle Development in Fish

Geertruy te Kronnié

In the axial musculature of adult fish two major populations of muscle fibres lay anatomically separated: 1) a triangular red zone at the level of the horizontal septum composed of red fibres and 2) the largest part of the myotome that is filled with the white muscle bulk.
The first locomotion of newly hatched fish larvae is probably powered by the red fibres and results in continuous stationary activity. Stimulation of the larvae results in burst-swimming which is probably powered by the mass of white fibres. During embryogenesis the two muscle compartments arise from muscle precursors in the segmental plate. Medial cells also known as adaxial cells will migrate radially away from the notochord and become the superficial layer of red cells. The population of lateral presomitic cells in the segmental plate remains deep in the myotome and differentiate into white muscle fibres.
By large scale genetic screens 43 genes that are required for the differentiation and maintenance of the axial musculature are being identified in Danio rerio. Here we discuss the phenotype of mutant fish that are involved in muscle development at the level of myotome differentiation, paraxial mesoderm segmentation and somite patterning. Signaling events leading to myogenic precursor cell specification and formation of muscle fibres are being unraveled and the first results begin to generate an insight in the molecular pathways involved in muscle development of fish. Moreover epigenetic factors that determine the final shape of the axial musculature are discussed.

Key words: development, fibre types, fish, musculature, somites.
Basic Appl Myol 10 (6): 261-267, 2000

Expression of Myofibrillar Proteins and Parvalbumin Isoforms in White Muscle of the Developing Turbot Scophthalmus Maximus (Pisces, Pleuronectiformes)

Bruno Focant, S. Collin, P. Vandewalle⁽¹⁾, and F. Huriaux

Expression of polymorphic myofibrillar and sarcoplasmic proteins was investigated in the fish Scophthalmus maximus (L.) undergoing metamorphosis. A range of electrophoretic techniques was used to monitor sequential synthesis of isoforms from hatching to the adult stage. Two isoforms (larval and adult) of myosin light chain LC2 and troponin-I were successively detected during turbot growth, in addition to variations in the peptide composition of myosin heavy chains. Two isoforms of troponin-T also appeared sequentially, but the first to make its appearance was not detected until the juvenile stage. The composition of alkali light chains, actin, tropomyosin, and troponin-C did not seem to change as the fish progressed through the different stages. Parvalbumin isoforms were isolated and their physico-chemical parameters defined. As in the other fish examined so far, there appeared a succession of larval (PA IIa and PA IIb) and adult (PA V) parvalbumin isoforms through the life of the fish. All these biochemical changes occurred gradually in the course of turbot development, and did not appear particularly related to metamorphosis but rather to physiological needs of the different growth stages.

Key words: development, metamorphosis, myofibrillar proteins, parvalbumin isoforms, Scophthalmus maximus, turbot.
Basic Appl Myol 10 (6): 269-278, 2000

Post-Hatching Development of Motor Innervation of Lateral Muscle in the Seabream Sparus aurata

Paolo Berardinelli, Giuseppe Radaelli⁽¹⁾, Anthea Rowlerson⁽²⁾, Pier Augusto Scapolo, Francesco Mascarello⁽¹⁾, and Alba Veggetti⁽³⁾

In many fish, both production of new muscle fibres and neurogenesis continue into juvenile life. To test the hypothesis that new motoneurons are produced to supply the expanding muscle target we used the seabream (Sparus aurata), which shows a many-fold increase in the number of fibres in lateral muscle during posthatching juvenile development. A motor nerve branch innervating a segment of epaxial lateral white muscle was identified, and the type and number of its axons were measured in fish of several larval and post-larval ages.
Contrary to expectation, total axon number was greatest in the larval fish (114.3±22.6); unmyelinated axons were found only in the larval nerves, and the number of myelinated axons increased only modestly over the ages examined, from 58.5±12.4 in larval fish to 77.5±7.3 in post-larval juveniles. We conclude that in seabream the larval nerve still includes axons of motoneurons destined to die during the normal developmental phase of target-dependence in addition to those axons which will survive into juvenile life, and that the definitive number of motoneurons is already present in the larval fish before the main increase in muscle fibre number occurs.

Key words: axon, larval, motoneuron, neurogenesis, post-larval.
Basic Appl Myol 10 (6): 279-284, 2000

Biochemical Changes in Gilthead Sea-Bream White Muscle During Post-Larval Growth

Gloria Isani, Giulia Andreani, Marta Monari, Luciano Dalla Libera⁽¹⁾, and Emilio Carpenè

In the present paper we present results of an investigation of the myofibrillar composition and pyruvate kinase (PK) activity in the white portion of lateral muscle of gilthead sea bream fed a commercial diet for five months during juvenile growth. The zinc and copper content of muscle and liver were also measured. Myofibrillar proteins extracted from the white muscle were mostly constituted by myosin as well as tropomyosin and actin, minor bands could be related to troponins. As reported for other fish, an apparent molecular weight of myosin LC3f higher than LC2f was found. Only minor changes in LC3f amounts were observed during the experimental period. A great variability in PK maximal activity was found, with values ranging from 175 to 453 U/g wet weight. The enzyme showed always hyperbolic saturation curves with the substrate phosphoenolpyruvate and was characterised by low Km. At the end of the experiment, when body mass of fish increased approximately three times, a significant increase of PK activity was measured. Zn concentrations were about ten time higher than Cu in both liver and muscle; on the other hand, the metal concentrations in the liver were about ten time higher than that of the muscle. In the latter no significant variations in metal concentrations were found.

Key words: gilthead sea-bream, metals, muscle, myofibrillar proteins, pyruvate kinase.
Basic Appl Myol 10 (6): 285-290, 2000

Family and Population Differences in Muscle Fibre Recruitment in Farmed Atlantic Salmon (Salmo salar)

Ian A Johnston, Sujatha Manthri⁽¹⁾, Billy Robertson⁽²⁾, Patrick Campbell⁽³⁾, David Mitchell⁽²⁾, and Richard Alderson⁽³⁾

The number of muscle fibres recruited to reach a given body weight in Atlantic salmon (Salmo salar L.) showed significant variation between two strains with different growth rates and life history characteristics. Patterns of fibre recruitment also varied between two-year classes of the same strain grown under different production conditions. The maximum diameter of fast muscle fibres was around 240 mm in all cases. The density of muscle fibres decreased with increasing body weight, although average values were relatively constant for fish of 3.5 to 6.5 kg. The variation in muscle fibre density within a family, often 65 to 140 fibres mm^-2 muscle, was significantly greater than that between families and/or strains. The significance of this variation in fibre recruitment for the textural and processing characteristics of the flesh is discussed.

Key words: Atlantic salmon, fibre recruitment, gaping, muscle growth, Salmo salar, texture.
Basic Appl Myol 10 (6): 291-296, 2000

Endurance Exercise Training Affects Fast White Axial Muscle in the Cyprinid Species Chalcalburnus Chalcoides Mento (Agassiz, 1832), Cyprinidae, Teleostei

Alexandra M. Sänger, and Ulrike Pötscher

This study undertakes an investigation on the effects of an endurance exercise training programme on axial muscle in the cyprinid species Chalcalburnus chalcoides mento (Agassiz, 1832), the Danube bleak. Previous studies on this species revealed biochemical evidence that it is white axial muscle which responds to an endurance training. To determine whether this could be verified also on a structural basis, red, intermediate and white axial muscle were investigated by means of histochemistry, electronmicroscopy and morphometry. Compared to other cyprinid species, the Danube bleak responds to an endurance exercise training regime with adaptive changes of fast white muscle rather than slow red muscle. Qualitative and quantitative analyses revealed that training induced significant increases in fibre diameters of intermediate and white muscle fibres and capillary supply in red and white muscle as well as volume density of myofibrils in red muscle fibres. Volume densities of mitochondria and lipid, and mATPase- and SDH-activity were unaffected. It is concluded that this adaptive strategy enables this fish with its typical burst-like mode of swimming (which was maintained for the whole period of the training) to meet the specific demands of an endurance exercise training.

Key words: endurance exercise training, muscle fibre types, electronmicroscopy, morphometry, capillarization.
Basic Appl Myol 10 (6): 297-300, 2000

Address correspondence to:

Dr. G. te Kronnié, Dept. Anatomy and Physiology, University of Padova, via Marzolo 3, 35131 Padova, Email truus@unipv.it.

Address correspondence to:

Dr. Bruno Focant, Université de Liège, Biologie cellulaire et tissulaire, Bât. Anatomie L3, 20, rue de Pitteurs, B-4020 Liège, Belgique.

Address correspondence to:

Prof. P.A. Scapolo, Dipartimento di Strutture, Funzioni e Patologie Animali e Biotecnologie, Università degli Studi di Teramo, 64020 Piano D’Accio (TE), Italy, tel. 00390861266850, fax 00390861266860, Email scapolo@ianve.vet.unite.it.

Address correspondence to:

Emilio Carpenè, Department of Biochemistry (Veterinary Section), University of Bologna, via Tolara 50, 40064 Ozzano Emilia (Bo), Italy.

Address correspondence to:

Ian A Johnston, Fish Muscle Research Group, Gatty Marine Laboratory, School of Biology, University of St Andrews, St Andrews, Fife, KY16 8LB, Scotland, UK.

Address correspondence to:

Dr. Alexandra M. Sänger, Institute of Zoology, Department of Vascular and Performance Biology, University of Salzburg, Hellbrunnerstraße 34, A-5020 Salzburg, Austria, tel. +43 662 8044-5611, fax +43 662 8044 5698, Email Alexandra.Saenger@sbg.ac.at.