Biomedical subjects

H Alami-Durante

Publications and source records attributed to H Alami-Durante.

4 recordsLinked to original sources

PubMed2001

Temperature and myogenic factor transcript levels during early development determines muscle growth potential in rainbow trout (Oncorhynchus mykiss) and sea bass (Dicentrarchus labrax).

The influence of changes in environmental temperature on the mRNA levels of myogenic regulatory factors (MRFs), i.e. MyoD and myogenin, as well as myosin heavy chain (MyHC) were studied during early larval development in rainbow trout and sea bass. Phosphoimager analysis of northern blots indicated that there is an optimum temperature for the RNA transcript levels of MRF and MyHC RNA in trout and in sea bass larvae. In the trout strain studied, the highest concentration for MRF and MyHC transcripts was found at 8 degrees C rather than 4 degrees C or 20 degrees C. In European sea bass, the highest concentrations of MRF and MyHC mRNA were observed at 15-20 degrees C rather than 13 degrees C. Raising sea bass larvae at 15 degrees C was associated with higher MyHC gene expression as well as a trend towards an increase in total muscle fibre number and higher growth rates after transfer at ambient temperature. Results suggest that mRNA levels of MRF and MyHC can be used to optimise early development. An experiment in which the temperature was changed illustrates the consequence of precise temporal expression of MRF genes in specifying muscle fibre number at critical stages during early development.

Animals↗

PubMed2000

Effects of environmental temperature on the development of the myotomal white muscle in larval carp (Cyprinus carpio L.).

A study was conducted on common carp (Cyprinus carpio L.) to determine the effects of environmental temperature experienced by embryos and larvae on the development of myotomal white muscle. Eggs from one female were divided into two groups following fertilisation and incubated at constant pre-hatch temperatures of 18 or 28 degrees C. At hatching, larvae from the 18 degrees C-incubated eggs were divided into two groups and either reared at the same temperature of 18 degrees C ('cold' group) or transferred over a period of 5 days (at 2 degrees C per day) to 28 degrees C ('transferred' group). Larvae hatched from eggs incubated at 28 degrees C were reared at the same temperature of 28 degrees C ('warm' group). Larvae were sampled at two developmental stages (stage 1, inflation of the back chamber of the swimbladder; stage 2, inflation of the front chamber of the swimbladder) and at 26 days post-hatching. The maturation of myotome shape during larval life was studied in parallel with the changes occurring in the organisation of white fibres. At stage 1, the epaxial part of the myotomes surrounding the vent had the shape of lamellae inclined backwards, and only one central layer of white fibres was present. At stage 2, the epaxial part of the myotomes began to acquire a V-shape, which was well developed at 26 days post-hatch. At stage 2 and at 26 days post-hatch, two layers of white fibres were identified: the initial central layer and a second apical layer. These differ in their orientation, the initial central layer being orientated backwards and the apical layer forwards, and in the mean fibre diameter, which is greater in the initial central layer. Studies on the effects of temperature (constant 18 degrees C, constant 28 degrees C, transfer from 18 to 28 degrees C at hatching) were carried out according to both the developmental stage and the length of the larvae. At stage 1, no significant differences were found between the three groups for larval standard length and muscle variables. The number of fibres in one quadrant of epaxial white muscle sectioned at the level of the vent was 100-111. At stage 2, there were significant differences between groups. Larval standard length and mass were higher in the cold group than in the warm group. The transferred larvae were of intermediate standard length but had a significantly higher cross-sectional area of white muscle than either of the other two groups. This increase in surface area was related to a 50 % greater fibre number (233) in the transferred larvae compared with the cold (165) or the warm (152) larvae. The increase in fibre number was more marked for large-diameter ( >20 microm) white fibres located in the initial central fibre layer (+58-72 % in transferred larvae) than in small-diameter ((less than equal to) 10 microm) white fibres mainly located in the apical layer (+18-35 %). In 26 days post-hatch samples, transferred larvae still showed a higher total number of white fibres than warm larvae, but the difference was no longer significant when the total number of white fibres was regressed against larval standard length, suggesting that this stimulation may be temporary.

Animals↗

PubMed1999

Identification and expression analysis of two developmentally regulated myosin heavy chain gene transcripts in carp (Cyprinus carpio).

Whilst developmentally regulated genes for the myosin heavy chain (MyoHC) have been characterised in mammalian, avian and amphibian species, no developmental MyoHC gene has previously been characterised in a species of fish. In this study, we identify two developmentally regulated MyoHC gene transcripts (named Eggs22 and Eggs24) in carp (Cyprinus carpio) and characterise their expression patterns during embryonic and larval development. The transcripts showed an identical temporal pattern of expression commencing 22 h post-fertilisation (18 degrees C incubation temperature), coincident with the switch from exclusive expression of genes for beta-actin to expression of genes for both beta- and alpha-actin, and continuing for 2 weeks post-hatching. No expression of these myosin transcripts was detected in juvenile or adult carp. Wholemount in situ hybridisation showed that both transcripts are expressed initially in the rostral region of the developing trunk and progress caudally. Both are expressed in the developing pectoral fin and protractor hyoideus muscles. However, the muscles of the lower jaw express only the Eggs22 transcript. No expression of either transcript was detected in cardiac or smooth muscle. A distinct chevron pattern of expression was observed in the myotomal muscle. This was shown to be caused by localisation of the mRNAs to the myoseptal regions of the fibres, the sites of new sarcomere addition during muscle growth, suggesting transport of MyoHC mRNA transcripts. The 3' untranslated region of the Eggs24 transcript contains a 10 base pair motif (AAAATGTGAA) which is shown to be also present in the 3' untranslated regions of MyoHC genes from a wide range of species. Possible reasons for the need for developmental isoforms of myosin heavy chain isoforms are discussed.

Amino Acid Sequence↗

PubMed1990

Growth of organs and tissues in carp (Cyprinus carpio L.) larvae.

Growth of some internal organs and tissues was studied in carp (Cyprinus carpio L.) in order to provide baseline information on the growth process during the first posthatching stages of fish, and to compare the trend observed in fish to that known in other animals. Growth of organs and tissues (liver, pancreas, trunk muscles, digestive tract, eyes, nervous system) was studied in rapidly growing carp (Cyprinus carpio L.) larvae by means of a quantitative histological method. Mean body weight of carp larvae rose from 1.8 mg at 2 days to 50.4 mg at 18 days. Between 4 and 18 days after hatching (yolk exhausted; exogenous food only), the average specific growth rates of organs were around 31% per day for the liver and pancreas, 28% per day for the trunk muscles, 26% per day for the digestive tract (without lumen) and 19% per day for the eyes and nervous system. Compared to the total volume of tissues, liver (k = 1.19), pancreas (k = 1.19), and trunk muscles (k = 1.09) showed positive allometry, digestive tract showed isometry (k = 1.00), and eyes (k = 0.76) and the nervous system (k = 0.73) showed negative allometry. This study demonstrated that the growth process of some organs (i.e. liver, pancreas and digestive tract) is different between larval and older stages of carp, and that the development of carp larvae exhibit the same order of allometry coefficients as do certain mammals (e.g. rabbit and lamb) in their early postnatal stages: nervous tissue, digestive tract, muscular tissue, liver.

Aging↗