Regulatory Effect of Magnesium Ions on Interaction of Prolactin and Somatotropin with Receptors on Granulosum Cells of the Cow Bos taurus

A comparative study of effects of Mg²⁺ ions on specific and competitive binding of the bovine somatotropic hormone (STH) and bovine prolactin (PL) with cells of cow granulosum is carried out. It is found that Mg²⁺ increases the level of specific binding of ¹²⁵I-PL with the cells at concentrations from 1 to 70 mM and decreases the level of specific binding of ¹²⁵I-STH at a concentration of 70 mM. Analysis of the data by Scatchard's method has shown that the decrease of the level of specific binding of ¹²⁵I-PL in the absence of MgCl₂ and ¹²⁵I-STH at a MgCl₂ concentration of 70 mM is caused mainly by a decrease of the number of active binding sites on the cells. Oppositely directed effects of the studied divalent cations on the capability of unlabelled STH (25 µg/ml) and PL (25 µg/ml) for cross-suppression of specific binding of ¹²⁵I-PL and ¹²⁵I-STH, respectively, with the granulosum cells have been revealed. At the same time, with increase of Mg²⁺ ion concentration, the degree of replacement of ¹²⁵I-STH and ¹²⁵I-PL with unlabelled STH and PL, respectively, did not change. The obtained results are considered in connection with electrostatic model of participation of the divalent cations in interaction of PL and STH with receptors on cells.     

Sulforaphane Suppresses Hepatitis C Virus Replication by Up-Regulating Heme Oxygenase-1 Expression through PI3K/Nrf2 Pathway

Hepatitis C virus (HCV) infection-induced oxidative stress is a major risk factor for the development of HCV-associated liver disease. Sulforaphane (SFN) is an antioxidant phytocompound that acts against cellular oxidative stress and tumorigenesis. However, there is little known about its anti-viral activity. In this study, we demonstrated that SFN significantly suppressed HCV protein and RNA levels in HCV replicon cells and infectious system, with an IC₅₀ value of 5.7 ± 0.2 μM. Moreover, combination of SFN with anti-viral drugs displayed synergistic effects in the suppression of HCV replication. In addition, we found nuclear factor erythroid 2-related factor 2 (Nrf2)/HO-1 induction in response to SFN and determined the signaling pathways involved in this process, including inhibition of NS3 protease activity and induction of IFN response. In contrast, the anti-viral activities were attenuated by knockdown of HO-1 with specific inhibitor (SnPP) and shRNA, suggesting that anti-HCV activity of SFN is dependent on HO-1 expression. Otherwise, SFN stimulated the phosphorylation of phosphoinositide 3-kinase (PI3K) leading Nrf2-mediated HO-1 expression against HCV replication. Overall, our results indicated that HO-1 is essential in SFN-mediated anti-HCV activity and provide new insights in the molecular mechanism of SFN in HCV replication.     

Production of cloned bovine embryos by somatic cell transfer into enucleated zona-free oocytes

Cloned bovine embryos were produced at the blastocyst stage. Prior to enucleation, oocytes were freed from the zona pellucida. Fibroblasts isolated from the bovine fetus were used as nuclear donors. Pairs of fetal fibroblasts and enucleated oocytes (cytoplasts) were glued in phytohemagglutinin solution under a binocular microscope. The subsequent electrofusion of 39 fetal fibroblast-cytoplast pairs yielded 36 reconstructed one-cell embryos (92.3%). After culturing in synthetic oviduct fluid for 7.5 days, seven cloned embryos developed to the blastocyst stage (19.4%) and six blastocysts were considered fit for transplantation. The applied technique of bovine embryo growth allowed 31.1% zona-free oocytes parthenogenetically activated by to reach the blastocyst stage.     

cDNA sequence and predicted primary structure of the gamma subunit from the ATP synthase from Chlamydomonas reinhardtii

The 1701-base nucleotide sequence (not including the poly(A) tail) of a cDNA for the gamma subunit of the ATP synthase from Chlamydomonas reinhardtii was determined. A start translation sequence, 23 bases in from the 5' end, initiates an 1074-base-long open reading frame. The sequence of the first 21 amino acids at the amino-terminal end of the mature gamma subunit from C. reinhardtii was determined and compared to the deduced amino acid sequence of the open reading frame. From this it was determined that the mature protein contains 323 amino acids, with the first 35 amino acids probably being part of the transit peptide. The length of the mature protein is the same as that for the mature gamma subunit from spinach, for which only a few of the amino acids of the transit peptide are known. The similarity of the two mature proteins at the nucleotide level is 56% while at the amino acid level it is 77%. In addition, the 3 cysteines, which in spinach are involved in the energy-linked catalytic functions of the ATP synthase, are conserved in the predicted amino acid sequence for the gamma subunit from C. reinhardtii. In contrast, the mature C. reinhardtii gamma subunit contains 3 additional cysteine residues not found in the spinach gamma subunit.