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C L Gallien

Publications and source records attributed to C L Gallien.

At least 37 records · Page 2Linked to original sources
PubMed1990

Myosin structure and thyroidian control of myosin synthesis in urodelan amphibian skeletal muscle.

Electrophoretic analysis in non-dissociating conditions reveals three types of myosin in adult urodelan amphibian skeletal muscles: 3 isoforms of fast myosin (FM), one isoform of intermediate myosin (IM) and one or two isoforms of slow myosin (SM). Each type is characterized by a specific heavy chain HCf (FM), HCi (IM) and HCs (SM), respectively. In all urodelan species, as in mammals, fast isomyosins associate HCf and the three fast light chains LC1f, LC2f, and LC3f. In most urodelan species the intermediate myosin contains LC1f and LC2f and can be considered as an homodimer of the alkali LC1f. However, in Euproctus asper, IM is characterized by the association of both slow and fast LC with HCi. Slow myosin is a hybrid molecule associating HCs with slow and fast LC. During metamorphosis, a myosin isoenzymic transition occurs consisting in the replacement of three larval myosins (LM) characterized by a specific heavy chain (HCI), by the adult isomyosins with lower electrophoretic mobilities. At the same time there is a change in the ATPase myofibrillar pattern, with the larval fiber types being replaced by adult fibers of types I, IIA and IIB. In the neotenic and perennibranchiate species, which do not undergo spontaneous metamorphosis, sexually mature larval animals present a change in the myosin isoenzymic profile, but no complete transition. The coexistence of larval and adult isomyosins and the persistence of transitional fibers of type IIC in the skeletal muscle are demonstrated. Experimental hypo- and hyperthyroidism indicate that thyroid hormone stimulates the regression of the larval isomyosins, possibly through indirect pathways. In contrast, the appearance and the persistence of the adult isomyosins seem to be independent of thyroid hormone. Thus, the control of the isoenzymic transition in the skeletal muscle of urodelan amphibians appears to imply indirect mechanisms, operating differently on each of the two phases of the complete transition.

Aging↗
PubMed1989

Myosin isoenzymes and their subunits in urodelan amphibian fast skeletal muscle. Coexistence of larval and adult heavy chains in neotenic individuals.

The distributions of native myosin isoforms were examined by electrophoresis under non-dissociating conditions, in the fast twitch dorsal skeletal muscle of young larvae, neotenic adults and metamorphosed adults of urodelan amphibians. Both heavy and light chains of myosin isoenzymes were analysed. In pyrophosphate acrylamide gel electrophoresis three isoenzymes were demonstrated in larval myosin; other isoforms of lower electrophoretic mobility were observed in metamorphosed adults myosin. Larval and adult isoenzymes were shown to coexist in myosin from neotenic adults. Analysis of heavy chains in denaturing conditions and proteolytic digestion revealed the sequential occurrence during development of two types of heavy chains, one larval and one adult, that coexist in the myosin of neotenic adults only. Analysis of light chain patterns under denaturing conditions revealed the existence of three fast light chains which displayed no modification during the course of development. The neotenic urodelan amphibian species model represents actually the only model in which the coexistence of larval (or neonatal) and adult heavy chains is maintained throughout life in adults.

Aging↗
PubMed1989

Thyroidal status and myosin isoenzymic pattern in the skeletal dorsal muscle of urodelan amphibians--the perennibranchiate Proteus anguinus.

In the perennibranchiate Proteus anguinus, larval myosin isoforms were shown to coexist for life with the adult isomyosins that appeared at the end of the larval stage. Analysis of the myofibrillar ATPase profile also revealed that a high percentage of immature fibers persisted in adults. A long-term treatment with large amounts of T3 had no effect on juvenile individuals. Applied to subadult animals it promoted a regression of larval myosin isoforms and a reduction in the percentage of immature fiber types. The regulative effect of T3 in the myosin isoenzymic transition may be delayed and depends on metabolic conditions, which suggests it is indirect.

Animals↗
PubMed1988

[Hormonal determination of the differentiation of striated skeletal muscle in urodele amphibians].

In the urodelan amphibian Pleurodeles waltlii, spontaneous external metamorphosis was correlated with an increase in the serum level of thyroxine (T4). Within the same period, a change occurred in the myofibrillar ATPase profile of the dorsal skeletal muscle; fibres of larval type were gradually replaced by transitional fibres (type IIC), then by adult fibres of the types I, IIA, and IIB. Likewise, a myosin isoenzymic transition was observed. In larval animals, myosin electrophoresis revealed 3 bands corresponding with isoforms having identical heavy chains (MHC), but different light chains (MLC). In the course of metamorphosis, the 3 larval isomyosins were replaced by 3 isoforms having the adult type MHC and different motility. In a related neotenic species, Ambystoma mexicanum, no spontaneous anatomic metamorphosis occurred; at the time it should theoretically take place, the serum T4 level remained low. The ATPase profile was modified, but transitional fibres that replaced the initial larval types appeared to be persistent, and adult fiber types appeared only in a small amount. Myosin isoenzymic transition was also incomplete, larval isoforms were still distinguished in the neotenic adults. Similar persistence of larval characters was observed in adult Proteus anguinus, a perennibranch that never undergoes anatomical metamorphosis. Experimental hypothyroidian Pleurodeles waltlii displayed no external metamorphosis, only the larval fibre types and isomyosins were detected in those animals. External metamorphosis was induced in Ambystoma mexicanum by a triiodothyronine treatment. A complete myosin isoenzymic transition was observed in metamorphosed animals. These results tend to indicate that a moderate increase in the level of thyroid hormones is sufficient to determine the production of the adult type MHC molecules and the differentiation of the corresponding myofibrillar types in the skeletal dorsal muscle of amphibians, while a marked increase would be necessary for repressing the initial larval feature.

Ambystoma↗
PubMed1987

Regulation by thyroid hormones of terminal differentiation in the skeletal dorsal muscle. I. Neonate mouse.

Changes both in the ATPase myofibrillar profile and in the electrophoretic pattern of myosin isoforms were examined in the mouse dorsal skeletal muscle (longissimus) during postnatal development. In the newborn, only type II C and a few type I fibers were present; differentiation into type II A and II B fibers took place during the 3 weeks following birth. During the same period, a transition from three neonatal isomyosins to four adult isoforms was observed. The two phenomena were related to a marked increase in the serum thyroid hormones levels. Hypothyroidism and hyperthyroidism experiments were performed. Hypothyroidism produced by propylthiouracil treatment of pregnant females and thiourea injections of the litters was shown to induce a complete inhibition of postnatal muscular differentiation. Hyperthyroidism produced by triiodothyronine treatment of the neonate mice significantly accelerated the myosin transition and the switch in the myofibrillar pattern. Our results suggest a primordial role for thyroid hormones in directly regulating the appearance of myosin and fiber adult types and in modulating directly or indirectly the disappearance of the neonatal types.

Adenosine Triphosphatases↗
PubMed1987

Regulation by thyroid hormones of terminal differentiation in the skeletal dorsal muscle. II. Urodelan amphibians.

In the urodelan amphibian Pleurodeles waltlii, spontaneous anatomical metamorphosis was correlated with an increase in the serum level of thyroxine (T4). It was also accompanied by a change in the myofibrillar ATPase profile of the dorsal skeletal muscle; fibers of larval type were gradually replaced by the adult fiber types I, II A, and II B. Likewise, a myosin isoenzymic transition was observed in dorsal muscle, larval isomyosins were replaced by adult isoforms. In a related species, Ambystoma mexicanum, in which no spontaneous external metamorphosis occurs under standard conditions, the serum T4 level was shown to remain low. During further development, the myofibrillar ATPase profile acquired the adult fiber types, but a high percentage of immature fibers of type II C persisted. Myosin isoenzymic transition was also incomplete; larval isoforms were still distinguished in the neotenic adults. In experimental hypothyroidian P. waltlii, no external metamorphosis occurred; the myofibrillar ATPase profile was of the immature type, and the larval isomyosins persisted. Triiodothyronine induced experimental anatomical metamorphosis in A. mexicanum; only limited changes in the myofibrillar ATPase profile resulted from the treatment, but a complete myosin isoenzymic transition was observed. These results tend to indicate that a moderate increase in the level of thyroid hormone is sufficient to induce the differentiation of adult fiber types, together with the production of adult myosin isoforms in the skeletal dorsal muscle of amphibians, while a pronounced increase would be necessary for repressing the initial larval features.

Adenosine Triphosphatases↗
PubMed1986

Partial purification of the maturation-promoting factor MPF from unfertilized eggs of Xenopus laevis.

A 200-fold purification of the maturation-promoting factor or MPF from unfertilized eggs of Xenopus laevis is reported for the first time. Purification was achieved by three successive column chromatographies on hydroxyapatite, trisacryl blue and L-arginine-agarose. The presence of MPF was assessed by the usual maturation criteria after injections of test material into immature stage VI unstimulated X. laevis oocytes: the precocious appearance of the maturation spot (within 45-120 min), the germinal vesicle breakdown, the presence of the first polar body and the second metaphase spindle. Purification was monitored by the decrease of the minimal amount of protein injected in a constant volume (50 nl) required to induce 50% frequency of germinal vesicle breakdown. This amount decreased from 500 ng in the crude extract to 2.5 ng in the 200-fold purified material. Analysis by SDS-PAGE of the crude extract showed about 40 Coomassie-blue-stained polypeptides with molecular masses ranging from 300 kDa to 20 kDa, whereas in the 200-fold purified MPF only 5 stained polypeptides were revealed, with molecular masses of 62, 53, 49, 39 and 37 kDa. In vitro phosphorylations for the detection of kinase activities for endogenous and exogenous substrates were monitored by analysis of autoradiograms of SDS-PAGE, after treatment of fractions with [gamma-32P]ATP. Only inactive fractions eluted from columns ahead of MPF, and fractions containing MPF activity were tested. Phosphorylation of numerous stained polypeptides was demonstrated in the crude MPF extract and exogenous substrates such as phosvitin, casein and histone type II-AS were also strongly phosphorylated. In the MPF fraction, purified on hydroxyapatite, a polypeptide of 53 kDa was more highly and specifically phosphorylated and the presence of kinase activities was observed for the above three exogenous substrates. In the 100-fold and 200-fold purified MPF, phosphorylation of endogenous substrates could not be shown and kinase activities for the above three substrates were drastically decreased as compared with the crude and purified MPF obtained after hydroxyapatite column chromatography. However, neither endogenous phosphorylations nor kinase activities with the above exogenous substrates could be shown in inactive fractions eluted ahead of MPF at the different purification steps. Some characteristics of the purified material are also described in this paper.

Animals↗
PubMed1984

Calmodulin during development and metamorphosis in urodelan amphibians.

Calmodulin isolated and purified to homogeneity from young larvae is very similar to that obtained from adult Pleurodeles waltlii and these proteins are almost identical to previously described vertebrate calmodulins. During P. waltlii development, an increase in total individual calmodulin content is observed after the heart beating stage. In dorsal axial muscle, calmodulin level which is very high at the beginning of larval life (premetamorphosis) decreases strikingly in the first part of prometamorphosis. Such an evolution is observed in Ambystoma mexicanum too. Then, a significant increase occurs during metamorphosis. In contrast, calmodulin level in P. waltlii cardiac ventricular muscle increases continuously from hatching to the end of metamorphic climax. Thyroxine treatment which promotes precocious metamorphosis in P. waltlii and experimental metamorphosis in neotenic A. mexicanum, induces a rapid and significant increase in muscle calmodulin concentration.

Ambystoma↗
PubMed1984

Changes in calmodulin level after fertilization and during first cleavage in the egg of the urodelan amphibian Pleurodeles waltlii.

We report three significant calmodulin rises related to Pleurodeles waltlii egg fertilization and following developmental events. These elevations are correlated to the major obvious Ca2+-dependent events: Na+-H+ exchange, activation of NAD kinase, triggering of cortical reaction, resumption of meiotic division II, initiation of DNA synthesis and regulation of cell division. Therefore, it is suggested that alterations in calmodulin level in fertilized egg may be part of the Ca2+-dependent regulatory mechanisms which turn on metabolisms, initiate development and govern cell cleavages.

Animals↗
PubMed1984

[Expression of hepatitis B virus (HBV) genome in the oocytes of two species of amphibians].

Xenopus laevis and Pleurodeles waltlii oocyte nuclei are injected with a recombinant plasmid pCP 10, carrying two hepatitis B virus (HBV) genomes in a tandem arrangement. Transcription occurs in oocytes of both species and production of viral RNAs is demonstrated; better quantitative results are obtained with P. waltlii oocytes. Two viral proteins are detected: Hepatitis B surface antigen (Ag HBs) and Hepatitis B core antigen (Ag HBc). These proteins can be shown only in oocyte homogenates, and not in the incubation media. Another viral marker (Ag HBe) was not detected.

Animals↗
PubMed1983

[Quantitative and qualitative analysis of the effects of various doses of beta-irradiation (50-5000 rads) on epidermal cells of embryos and larvae of Pleurodeles waltlii Mich. (Amphibia, Urodela)].

Embryos of Pleurodeles waltlii at the hatching stage were irradiated with doses of 50 to 5 000 rad. From 70 to 500 rad chromosomal aberrations appear; they are studied respectively 24,48 hours and 3 weeks after the treatment. Breakages are observed, that may be followed by rearrangements, i.e. acentric, telocentric and dicentric fragments, chromatid translocations and chromosome translocations. With time, the cells showing the most severe abnormalities are eliminated by the developing larvae. From 1 000 rad cytoplasmic structures (membrane systems and mitochondria) are alterated .

Animals↗
PubMed1975

[Transplantation into the blastocoel of Pleurodeles waltlii Michah., of blastomers isolated from blocked blastulae obtained from interspecific nuclear transplants between Ambystoma mexicanum Shaw. and Ambystoma dumerilii Dugès (urodele amphibians)].

Ectodermic blastomeres from arrested nucleocytoplasmic blastulae obtained by nuclear graft between Ambystoma mexicanum (A. m.) and Ambystoma dumerilii (A. d.), are transplanted in the blastocoele of recipient Pleurodeles waltlii blastulae. Histo-autoradiographic analysis shows that hybrid cells have cellular affinities and multiplication capacities very different from normal Ambystoma mexicanum blastulae isolated cells. The possibility that a revitalisation of lethal blastomeres can occur should not be retained.

Ambystoma↗