Molecular characterization and expression analysis of the ß-actin gene from the ridgetail white prawn Exopalaemon carinicauda.

Actin is a highly conserved protein that is found in all eukaryotic cells, and has been widely used as an internal control gene in gene expression studies. In this study, we cloned an actin gene (named Ecß-actin) from Exopalaemon carinicauda and determined its expression levels. The full-length cDNA of Ecß-actin was 1335 bp long, comprising a 1131-bp ORF encoding 376 amino acids, a 65-bp 5'-UTR, and a 139-bp 3'-UTR with a poly(A) tail. The A + T content was approximately 79% in the 3'-UTR of the Ecß-actin mRNA. The 3'-UTR contained two repeats of the AUUUA motif. The putative protein Ecß-actin showed high identity (97-99%) with other actins from various species. Phylogenetic analysis revealed that Ecß-actin belongs to Crustacea, although it formed a singleton sub-branch that was located a short distance from crabs and other shrimp species. Ecß- actin expression was detected in the hepatopancreas, ovary, muscle, gill, stomach, and hemocytes, and was strongly expressed in the hemocytes and ovary of E. carinicauda. Ecß-actin mRNA expression varied during ovarian development, with high levels observed at stages I and V. Therefore, caution should be taken when using the Ecß-actin gene as an endogenous control gene.

Inhibitory effects of spironolactone on myocardial fibrosis in spontaneously hypertensive rats.

This study evaluated the inhibitory effects of spironolac-tone, a non-selective aldosterone receptor antagonist, on hypertension-induced myocardial fibrosis. Collagen I and III contents was detected in the myocardial tissue of spontaneously hypertensive rats (SHRs) after spironolactone administration. Twenty male SHRs were assigned to the spironolactone group or control group (N = 10 each); 7 Wistar-Kyoto rats (WKY) were also used. Spironolactone dissolved in ddH2O was administered via gavage at a dosage of 20 mg·kg(-1)·day(-1). Meanwhile, the control and WKY groups were administered equivalent volumes of ddH2O for 16 weeks. Western blotting was used to detect the contents of collagen I in myocardial tissue; observations were performed using polarizing microscopy, and the area integration and ratio of collagen I/III were subsequently calculated. Compared to the WKY group, col-lagen I synthesis was significantly higher in the control group (1.87 ± 0.2 vs 1.21 ± 0.7, P < 0.05). After 16 weeks of treatment, collagen I contents were significantly lower in the spironolactone group than in the control group (1.42 ± 0.05 vs 1.87 ± 0.2, P < 0.05). The ar-eas of collagen I and collagen I/III ratio were significantly smaller in the spironolactone group than in the control group (6400 ± 259 vs 12,019 ± 734 pixels, 15.64 ± 1.34 vs 20.8 ± 3.04 pixels, respec-tively; P < 0.05). However, there were no significant differences in the area of collagen III among the three groups. In conclusion, spi-ronolactone improves myocardial collagen deposition, preventing myocardial fibrosis in SHRs.