Thermal acclimation and muscle contractile properties in cyprinid fish

After several weeks of cold acclimation, the swimming performance of some fish is increased at low temperatures and decreased at high temperatures. The temperature compensation of locomotory activity involves changes in central patterns of muscle fiber recruitment and in the properties of the peripheral nervous system and muscle tissues. In some freshwater fish belonging to the family Cyprinidae, including the goldfish (Carassius auratus), the common carp (Cyprinus carpio), and the roach (Rutilus rutilus), the intrinsic contractile properties of muscles are modified by thermal acclimation. Parameters that can be altered by temperature acclimation in both fast and slow muscle fibers include isometric twitch contraction time, maximum force production, and unloaded shortening speed. The molecular mechanisms responsible for these changes in contractility are discussed.

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Isolation and characterisation of mRNA encoding the salmon- and chicken-II type gonadotrophin-releasing hormones in the teleost fish Rutilus rutilus (Cyprinidae)

Journal of Molecular Endocrinology ◽

10.1677/jme.0.0190337 ◽

1997 ◽

Vol 19 (3) ◽

pp. 337-346 ◽

Cited By ~ 21

Author(s):

MC Penlington ◽

MA Williams ◽

JP Sumpter ◽

M Rand-Weaver ◽

D Hoole ◽

...

Keyword(s):

Cladistic Analysis ◽

Rutilus Rutilus ◽

Fish Host ◽

Open Reading Frames ◽

Roach Rutilus Rutilus ◽

Significant Similarity ◽

Coding Regions ◽

Goldfish Carassius Auratus ◽

Gonadotrophin Releasing Hormone ◽

Rapid Amplification

The complementary DNAs (cDNA) encoding the [Trp7,Leu8]-gonadotrophin-releasing hormone (salmon-type GnRH; sGnRH:GeneBank accession no. u60667) and the [His5,Trp7,Tyr8]-GnRH (chicken-II-type GnRH; cGnRH-II: GeneBank accession no. u60668) precursor in the roach (Rutilus rutilus) were isolated and sequenced following reverse transcription and rapid amplification of cDNA ends (RACE). The sGnRH and cGnRH-II precursor cDNAs consisted of 439 and 628 bp, and included open reading frames of 282 and 255 bp respectively. The structures of the encoded peptides were the same as GnRHs previously identified in other vertebrates. The sGnRH and cGnRH-II precursor cDNAs, including the non-coding regions, had 88.6 and 79.9% identity respectively, to those identified in goldfish (Carassius auratus). However, significant similarity was not observed between the non-coding regions of the GnRH cDNAs of Cyprinidae and other fish. The presumed third exon, encoding partial sGnRH associated peptide (GAP) of roach, demonstrated significant nucleotide and amino acid similarity with the appropriate regions in the goldfish, but not with other species, and this may indicate functional differences of GAP between different families of fish. cGnRH-II precursor cDNAs from roach had relatively high nucleotide similarity across this GnRH variant. Cladistic analysis classified the sGnRH and cGnRH-II precursor cDNAs into three and two groups respectively. However, the divergence between nucleotide sequences within the sGnRH variant was greater than those encoding the cGnRH-II precursors. Consistent with the consensus developed from previous studies, Northern blot analysis demonstrated that expression of sGnRH and cGnRH-II was restricted to the olfactory bulbs and midbrain of roach respectively. This work forms the basis for further study on the mechanisms by which the tapeworm, Ligula intestinalis, interacts with the pituitary-gonadal axis of its fish host.

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