In
Rana esculenta in an in vitro system, hepatic vitellogenin synthesis can be induced by growth hormone in both sexes. In this study: (1) the ability of this hormone to induce transcription of the ...VTG gene was determined, and (2) this ability was compared with that of estradiol-17β. The results indicate that growth hormone stimulates VTG mRNA transcription both in vivo and in vitro, in both sexes. The levels of mRNA are related to protein levels in the medium. In addition, seasonal variation occurs in the VTG gene transcription under growth hormone and estradiol-17β; indeed the more active inducer was growth hormone during the reproductive period and estradiol-17β during the prereproductive phase.
Objetivou-se com este trabalho avaliar o efeito da incorporação ao solo de cama-de-frango e de fósforo sobre o crescimento e a produção da fáfia. Os tratamentos foram cinco doses de cama-de-frango ...semidecomposta (0, 5, 10, 15 e 20 t ha-1), com e sem o uso de fósforo (200 kg ha-1 de P2O5, na forma de superfosfato triplo), arranjados em esquema fatorial 5 x 2, no delineamento experimental blocos casualizados, com quatro repetições. As alturas das plantas variaram em função das doses da cama-de-frango, sendo maiores (138,50 cm) sob 20 t ha-1. As produções de massas frescas e secas de folhas, caules e raízes foram influenciadas significativamente pela interação cama-de-frango e fósforo. As maiores produções de massa fresca e seca de folhas (597 kg ha-1 e 100 kg ha-1, respectivamente) foram obtidas com a dose de 20 t ha-1 de cama-de-frango, sem o uso de fósforo. Para caules, as maiores produções de massa fresca e seca (7.757 kg ha-1 e 2.633 kg ha-1, respectivamente) foram obtidas com a dose de 20 t ha-1 de cama-de-frango, com o uso de fósforo. As maiores produções de massa fresca e seca de raízes (9.065 kg ha-1 e 377 kg ha-1, respectivamente) foram obtidas com a dose de 20 t ha-1 de cama-de-frango, sem o uso de fósforo. Os teores médios de N, P e K das folhas foram de 8,60; 0,88 e 4,46 g kg-1, respectivamente. Os teores de Ca e Mg foram máximos (7,56 e 5,12 g kg-1, respectivamente) com o uso de 20 t ha-1 de cama-de-frango, independente do uso de P. Nas raízes os teores médios de N, P e Mg foram de 2,74; 0,27 e 0,96 g kg-1, respectivamente. O teor de K reduziu linearmente com as doses de cama-de-frango e o de Ca foi máximo com o uso de 20 t ha-1. Para se obter maiores produções de massas frescas e secas de folhas e raízes, as plantas de fáfia devem ser cultivadas com cama-de-frango (20 t ha-1) incorporada ao solo, sem necessidade de adição de fósforo.
The present study explored alternative strategies to improve the health status and growth metabolism in cultured juvenile fish. In this context the effects of alginic acid administration on the ...welfare of rainbow trout juveniles were investigated. Both the hepatic gene expression of heat shock protein 70 and the cortisol plasma levels were evaluated in order to estimate the possible beneficial role of alginic acid in improving animal well-being. At the same time the body weight was measured and was correlated with the hepatic expression of insulin-like growth factor I, myostatin, and two isoforms of the thyroid receptor. Finally, improvement of the immune system was investigated by monitoring the expression of innate immune-related genes, such as interleukin1β, interleukin8 and toll-like receptor3, in the spleen. The data obtained demonstrated an improvement in the welfare of rainbow trout juveniles, revealed by growth and innate immune response enhancement by alginic acid administration. These results may be of great importance for the further development of more sustainable aquaculture practices, and can be considered as a biotechnological application to produce a safer product for human health.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This study investigated enzymatic activity of cathepsins and the membrane integrity of zebrafish (
Danio rerio) oocytes after freezing to −196
°C using controlled slow cooling. Stage III oocytes ...(>0.5
mm), obtained through dissection of anaesthetised female fish and desegregation of ovarian cumulus, were exposed to 2M methanol or 2
M DMSO (both prepared in Hank’s medium) for 30
min at 22
°C before being loaded into 0.5
ml plastic straws and placed into a programmable cooler. After controlled slow freezing, samples were plunged into liquid nitrogen (LN) and held for at least 10
min, and thawed by immersing straws into a 27
°C water bath for 10
s. Thawed oocytes were washed twice in Hank’s medium. Cathepsin activity and membrane integrity of oocytes were assessed both after cryoprotectant treatment at 22
°C and after freezing in LN. Cathepsin B and L colorimetric analyses were performed using substrates Z-Arg-ArgNNap and Z-Phe-Arg-4
MβNA-HCl, respectively, and 2-naphthylamine and 4-methoxy-2-naphthylamine were used as standards. Cathepsin D activity was performed by analysing the level of hydrolytic action on haemoglobin. Oocytes membrane integrity was assessed using 0.2% Trypan blue staining for 5
min. Analysis of cathepsin activities showed that whilst the activity of cathepsin B and D was not affected by 2
M DMSO treatment, their activity was lowered when treated with 2M methanol. Following freezing to −196
°C, the activity of all cathepsins (B, D and L) was significantly decreased in both 2
M DMSO and 2
M methanol. Trypan blue staining showed that 63.0
±
11.3% and 72.7
±
5.2% oocytes membrane stayed intact after DMSO and methanol treatment for 30
min at 22
°C, respectively, whilst 14.9
±
2.6% and 1.4
±
0.8% stayed intact after freezing in DMSO and methanol to −196
°C. The results indicate that cryoprotectant treatment and freezing modified the activities of lysosomal enzymes involved in oocyte maturation and yolk mobilisation.
In the frog Rana esculenta, previous works have clearly demonstrated the relationship between growth hormone (GH) and hepatic synthesis of vitellogenin throughout both in vivo and in vitro ...experiments. Vitellogenin is a large precursor molecule of yolk protein lipovitellin and phosvitin, synthesized by the liver under multihormonal control. The present study evaluates the effects of GH and insulin-like growth factor-I (IGF-I) in cultured frog hepatocytes by measuring the amount of vitellogenin in the culture medium, using ELISA.
Plasma growth hormone (GH), prolactin (PRL), and vitellogenin (VTG) concentrations were determined during the annual reproductive cycle of the frog Rana esculenta. Plasma GH and PRL were measured ...using a RIA that employed purified bullfrog (Rana catesbeiana) GH and PRL as standards and radioligand, and their respective antibodies. Using ELISA, plasma VTG titers were related to ovarian weight. GH, PRL, and VTG displayed different trends related to season and sex. In male frogs the GH and PRL trends have been found parallel, showing the highest concentrations (35 and 85 ng/ml, respectively) during the winter months. In the female frogs, the GH trend behaved differently from that in males; in fact, plasma GH changed during the annual reproductive cycle, showing two main peaks occurring during the reproductive period and the autumn ovarian recrudescence that are well correlated with the vitellogenesis as well as with the main changes in ovarian weight.
The sea bass
Dicentrarchus labrax is a pelagic egg spawner; sinking eggs are unable to develop into embryos, and this is a limitation in the controlled reproduction of this species. The eggs were ...divided into good and poor quality, by virtue of their ability to float or sink in seawater. High levels of cathepsins B, D, and L were detected in the eggs, whereas no cathepsin A, C, and E activity was detected. Cathepsin D was found at significantly higher levels in sinking eggs, whereas cathepsin L was more abundant in floating eggs. Since degradation of yolk proteins is essential for the early development of the embryo, the levels of cathepsins A, B, C, D, E, and L were tested in different stages of embryo development. Cathepsin A activity was detectable from the morula stage at which time cathepsin B activity reached its maximal level. Cathepsins A and L reached maximal activity during segmentation, and this corresponded with major changes in the electrophoretic pattern of yolk proteins during embryogenesis suggesting their involvement in yolk protein mobilization at this time. Cathepsin D reached its maximal activity during hatching.
In mammals, proopiomelanocortin (POMC)-related peptides are involved in reproductive processes at both the hypothalamopituitary
and ovarian levels. Through immunocytochemical and physiological in ...vitro studies, evidence for a diffuse POMC-related opioid
system in the lizard Podarcis s. sicula is provided. In the lizard ovary, beta-endorphin (beta-EP)-like immunoreactive cells
were observed within the granulosa layer; the immunoresponse showed seasonal variation, being most pronounced in the winter
ovary. HPLC followed by immunoassay showed that acetyl beta-EP is the main form of POMC-related peptide in both pituitary
and ovary. In vitro studies showed that picomolar amounts of beta-EP stimulate follicular estrogen production during both
the reproductive and winter phases; induction was found to be higher in the reproductive phase. The data reported here provide
evidence for the physiological role played by beta-EP in the reproductive function of Podarcis s. sicula via induction of
ovarian production of estradiol-17 beta, which is the main factor responsible for the vitellogenic process.
Plasma vitellogenin and 17 beta-estradiol concentration were determined during the annual reproductive cycle of the female lizard Podarcis s. sicula Raf. living around Naples. Plasma vitellogenin was ...purified from estrogenized males for characterization and to raise specific immune serum. Using ELISA, plasma vitellogenin titers were determined in relation to ovary weight; plasma 17 beta-estradiol was measured by RIA method. Native vitellogenin was present as two polypeptide bands: alpha and beta. The electrophoretic patterns, studied in normal male and estrogenized male and female, showed vitellogenin to be a protein present in female and in estrogenized male plasma but not in normal males. Lizard monomeric VTG, determined by SDS-PAGE, was about 200 kDa. Correlations between seasonal ovarian weight variations and plasma vitellogenin and 17 beta-estradiol suggest that ovarian development in Podarcis depends on plasma vitellogenin synthesis, which in turn relies on plasma estradiol levels. The two ovulatory waves observed in this study coincided with the two peak values of plasma vitellogenin and 17 beta-estradiol.
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