جستجوی مقالات مرتبط با کلیدواژه « Persian sturgeon » در نشریات گروه « زیست شناسی »

This study aims to analyze the fishing trend and predict the future catch of Persian sturgeon (Acipenser persicus) stocks by DB-SRA and dynamic models in the southern shores of the Caspian Sea. The results showed that, according to the size of the initial population in 2018, equal to 153 spicemens(mean weigth 30kg); assuming a constant rate of catch from the population equivalentto 0.2 per year (half of the current catch); until the next 30 years (2050), the amount of catching of Persian sturgeon will increase until the stocks of this species have the ability to fully restore themselves. While assuming the current catch rate, there has been a sharp decrease in the catch of fish in the southern shores of the Caspian Sea; it is estimated that the stocks of this type of sturgeon fish will be extinct by 2050

Considering the importance of Caspian Sea sturgeon conservation according to CITES rules, finding effective and efficient methods for tracing and identifying sturgeon species are necessary. Residual DNA detection in fish ponds can be used as a model for tracing fish environmental DNA (eDNA) in rivers and seas. This method of DNA detection is non-invasive and advantageous for the conservation of critically endangered sturgeons. Sampling was done from the water of the Persian sturgeon fish pond and fixed with precipitation premix solution (ethanol and acetate sodium). DNA was extracted from fixed water, and fine tissue of two sturgeon species in the Caspian Sea, Sterlet, and Siberian sturgeon. The positive specificity of primers was checked by conventional PCR for sturgeons with fine tissue DNA samples. The linear relationship between the threshold cycle (ct) value and the Persian Sturgeon DNA concentration was measured by the Mini-Barcoding quantitative real-time PCR. DNA samples of fish ponds generated a curve that could not be produced in negative control and irrelevant (non-sturgeon) genomic DNA.  Although residual DNA of Persian sturgeons was detected in fish pond water at picogram level through the quantitative method, molecular diagnosis with this method can confirm only the existence of sturgeon species (in general) in fish ponds. In identifying residual DNA in the picogram level of the Persian sturgeon fish pond, SYBER Green real-time PCR method can be an acceptable method for barcoding with high efficiency compared to other methods such as conventional PCR method and non-invasive which is advantageous for the conservation of critically endangered sturgeons.

In the present study, different stages of the ontogeny of the liver and pancreas in the Acipenser persicus were illustrated from hatching until 36 days post hatching (dph) by histological techniques. The histological sections (sagittal plane) were made by a microtome at a thickness of 5 µm and stained with Hematoxylin and Eosin, Periodic Acid-Schiff and Masson's trichrome. Based on the results, in 2 dph, liver stroma was formed and stellate hepatocytes included numerous vacuoles with nuclei situated parametrically. On 10 dph, the pancreas was observed between the liver and anterior part of the intestine for the first time. Exocrine pancreatic cells were organized in acini. At 18 dph, the central veins and hepatic sinusoids were remarkably apparent in the middle of the liver parenchyma. The pancreas grew as a basophilic organ and it was situated in the posterior intestine on the 22-dph, bile duct, portal vein and hepatic artery was acquiring their structure in connective tissue. On day 36, the liver was characterized by an enlarged and organized form. Formation of the hepatopancreatic tissue is completed within 16 to 36 days after hatching.

The biological activity of Persian sturgeon (PS) enfolded crude recombinant growth hormone (rGH) recovered from inclusion bodies (IB) estimated by administrating to fish fingerlings. The psrGH IBs expressed in E. coli were dissolved in cold guanidine HCl solution, immediately diluted ~1000 fold in cold sodium chloride 0.9% solution do not allow the rGH folding and administrated to fishes. It was revealed that intramuscularly injections of rGH at dosage of 0.5 μg/ g once a week for 8 weeks significantly accelerate the growth of fishes. Comparison of the mean growth rate and daily weight and length gain dates of Persian sturgeon fingerlings administrated by pure and crude grade rGH revealed the existence at list 2-5% potentially biologically active psrGH molecules in IBs. This fact enables to avoid the time and cost consuming processes of refolding and purification of rGHs.

Administering growth hormone increases growth rate of cultured fish. The aim of this study was isolation and synthesize of Persian sturgeon GH cDNA. The total RNA was extracted from pituitary gland of Persian sturgeon and cDNA was synthesized. The full-length cDNA sequence of Persian sturgeon contains a 645 nucleotide open reading frame, which encoding a 214 amino acid residues. The position of the signal peptide cleavage site was predicted to be at position 72. After cleaving of a signal peptide of 24 amino acid resi dues, a mature peptide of 190 aa formed. The blast observed that the PS pre GH have highest nucleotide sequence similarity with Acipenseridae family and mammals GH. Secondary structure and tertiary structure of Persian sturgeon growth hormone gene were prediction by online software. The secondary structure of the GH was revealed the predomination of a- helix (> 55%), the domains of high conservation across the vertebrate GH protein. The predicted 3D structure of Persian sturgeon growth hormone attribute to the typical 4-a-helix bundle protein conformation, the characteristic 3-D confirmation of growth hormones.

Egg envelope or otherwise called zona radiata (ZR) is an acellular area that originates next to oolemma externally. It grows and thickens gradually from oolemma and follicular epithelium both. Microscopic studies on the tissue sections hava shown that during developmental stages of oocytes, ZR could not be observed at stage I (Primary growth stage) in Acipenser persicus. It appeared in stage II (Cortical alveolar stage) and during stage III (vitellogenesis), ZR thickness was greatest and had highest complexity. The striated appearance of ZR at this stage, were identified to be pore-canals involved in yolk material transportation. In stage IV (Maturation stage), a decline was observed in ZR thickness and complexity, a process which continued after fertilization. In mature egg, an uneven layer of chorion over ZRe (ZR, external) and a jelatinous coat extrachorion were developed. Immediately after fertilization, ZRi (ZR, internal) turned to a homogenous layer (fertilization envelope), probably because of cortical reaction. 30 minutes after fertilization, two layers recognized in ZRi and chorion and extrachorion were disappeared.