Effects of human immunodeficiency virus type 1 nef and tat genes on rat PC12 pheochromocytoma cells

The regulatory genes nef and tat of the human immunodeficiency virus type 1 (HIV-1) were transferred into the rat pheochromocytoma cells (line PC12) under the control of the eukaryotic promoters. Proliferative activity of the PC12 cells transfected with the tat HIV-1 gene was substantially increased as compared to the control. Conversely, the nef gene introduced into the cultivated PC12 cell caused inhibition of their proliferative activity and formation of cell agglomerates resembling in morphology the multinuclear syncytial cells. Thus, our results suggest that the tat gene activates proliferation of the cultivated PC12 cells, whereas the nef gene inhibits proliferation of the same cells. We have obtained for the first time a direct indication for the possible role of the nef gene in formation of multinuclear T-lymphocyte and macrophage syncytium in HIV-1-infected patients. The HIV-1 nef and tat genes had no significant effect on the neuronal differentiation of the PC12 cells induced by the nerve growth factor (NGF).     

Long non‐coding RNAs in melanoma

Melanoma is the most lethal cutaneous cancer with a highly aggressive and metastatic phenotype. While recent genetic and epigenetic studies have shed new insights into the mechanism of melanoma development, the involvement of regulatory non‐coding RNAs remain unclear. Long non‐coding RNAs (lncRNAs) are a group of endogenous non‐protein‐coding RNAs with the capacity to regulate gene expression at multiple levels. Recent evidences have shown that lncRNAs can regulate many cellular processes, such as cell proliferation, differentiation, migration and invasion. In the melanoma, deregulation of a number of lncRNAs, such as HOTAIR, MALAT1, BANCR, ANRIL, SPRY‐IT1 and SAMMSON, have been reported. Our review summarizes the functional role of lncRNAs in melanoma and their potential clinical application for diagnosis, prognostication and treatment.     

Protective effect of bixin on carbon tetrachloride-induced hepatotoxicity in rats

Background

The liver is an important organ for its ability to transform xenobiotics, making the liver tissue a prime target for toxic substances. The carotenoid bixin present in annatto is an antioxidant that can protect cells and tissues against the deleterious effects of free radicals. In this study, we evaluated the protective effect of bixin on liver damage induced by carbon tetrachloride (CCl₄) in rats.

Results

The animals were divided into four groups with six rats in each group. CCl₄ (0.125 mL kg^-1 body wt.) was injected intraperitoneally, and bixin (5.0 mg kg^-1 body wt.) was given by gavage 7 days before the CCl₄ injection. Bixin prevented the liver damage caused by CCl₄, as noted by the significant decrease in serum aminotransferases release. Bixin protected the liver against the oxidizing effects of CCl₄ by preventing a decrease in glutathione reductase activity and the levels of reduced glutathione and NADPH. The peroxidation of membrane lipids and histopathological damage of the liver was significantly prevented by bixin treatment.

Conclusion

Therefore, we can conclude that the protective effect of bixin against hepatotoxicity induced by CCl₄ is related to the antioxidant activity of the compound.     

3-Aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione for circumvention of anticancer drug resistance

A series of 3-aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione was synthesized by Mannich reaction or by the transamination of 3-dimethylaminomethyl 4,11-dihydroxy- or 4,11-dimethoxynaphtho[2,3-f]indole-5,10-dione. The potency of novel derivatives was tested on a National Cancer Institute panel of 60 human tumor cell lines as well as in cells with genetically defined determinants of cytotoxic drug resistance, P-glycoprotein (Pgp) expression, and p53 inactivation. Mannich derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione with an additional amino function in their side chain, demonstrated equal cytotoxicity against the parental K562 leukemia cells and their Pgp-positive subline, whereas the latter showed approximately 7-fold resistance to adriamycin, a Pgp transported drug. 3-(1-Piperazinyl)methyl and 3-(quinuclidin-3-yl)aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione killed HCT116 colon carcinoma cells (carrying wild type p53) and their p53-null variant within the similar range of concentrations. We conclude that Mannich modification of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione, especially when cyclic diamine (e.g., piperazine, quinuclidine) is used, confers an important feature to the resulting compounds, namely, the potency for tumor cells otherwise resistant to a variety of anticancer drugs.     

Effects of human presenilin 1 isoforms on proliferation and survival of rat pheochromocytoma cell line PC12

Missense mutations in human presenilin 1 gene (hPS1) cause an autosomal dominant, early onset form of Alzheimer's disease (AD). To study effects of mutant presenilin on processes of cell growth, differentiation, and susceptibility to apoptotic signals, we produced a series of rat pheochromocytoma PC12 poly- and monoclonal cell lines stably expressing wild type hPS1 and hPS1 with mutations in amino (N-) and carboxyl (C-) terminal regions of the PS1 protein. Employing a heterologous rat PC12 cell system, we demonstrated that: 1) AD mutations inhibit, in part, processing of hPS1 holoprotein; 2) negative selection against highly expressed hPS1 may occur in polyclonal cell cultures; 3) expression of N-terminus mutant (M146V) hPS1 increases susceptibility to apoptosis in differentiated neuronal PC12 cells under deprivation conditions; 4) monoclones with hPS1 C-terminal AD mutation (C410Y) have lower proliferation rates than monoclones expressing wild type hPS1 under deprivation conditions and during NGF-induced neuronal differentiation. The data demonstrate deleterious effect of PS1 AD mutations. The effect depends on the level of expression of the hPS1 isoforms, the number of passages, and trophic and differentiation conditions used for growing PC12 cells.     

A new species of Mesocoelium (Digenea: Mesocoeliidae) found in Rhinella marina (Amphibia: Bufonidae) from Brazilian Amazonia

Mesocoelium lanfrediaesp. nov. (Digenea: Mesocoeliidae) inhabits the small intestine of Rhinella marina (Amphibia: Bufonidae) and is described here, with illustrations provided by light, scanning electron microscopy and molecular approachs. M. lanfrediae sp. nov. presents the typical characteristics of the genus, but is morphometrically and morphologically different from the species described previously. The main diagnostic characteristics of M. lanfrediae sp. nov. are (i) seven pairs of regularly-distributed spherical papillae on the oral sucker, (ii) ventral sucker outlined by four pairs of papillae distributed in a uniform pattern and interspersed with numerous spines, which are larger at the posterior margin and (iii) small, rounded tegumentary papillae around the opening of the oral sucker, which are morphologically different from those of the oral sucker itself, some of which are randomly disposed in the ventrolateral tegumentary region of the anterior third of the body. Addionally, based on SSU rDNA, a phylogenetic analysis including Brachycoeliidae and Mesocoeliidae taxa available on GenBank established the close relationship between M. lanfrediae sp. nov. and Mesocoelium sp.     

Phosphorylation and biosynthesis of high molecular weight proteins of tumor nuclear matrix

INTRODUCTIONAsearlyasin1948wehavefr8CtionatedisolatednucleifromnormalandtumorcellsbyextractionwithiMNaCIanddilutealkali[1].Thenuclearresiduewasthenstudiedmorethoroughly[2,3].Lateron,sillillarproteinousnuclearresidueswereisolatedbyotherworkers[46]andasstud…     

Algorithms and software for support of gene identification experiments

MOTIVATION: Gene annotation is the final goal of gene prediction algorithms. However, these algorithms frequently make mistakes and therefore the use of gene predictions for sequence annotation is hardly possible. As a result, biologists are forced to conduct time-consuming gene identification experiments by designing appropriate PCR primers to test cDNA libraries or applying RT-PCR, exon trapping/amplification, or other techniques. This process frequently amounts to 'guessing' PCR primers on top of unreliable gene predictions and frequently leads to wasting of experimental efforts. RESULTS: The present paper proposes a simple and reliable algorithm for experimental gene identification which bypasses the unreliable gene prediction step. Studies of the performance of the algorithm on a sample of human genes indicate that an experimental protocol based on the algorithm's predictions achieves an accurate gene identification with relatively few PCR primers. Predictions of PCR primers may be used for exon amplification in preliminary mutation analysis during an attempt to identify a gene responsible for a disease. We propose a simple approach to find a short region from a genomic sequence that with high probability overlaps with some exon of the gene. The algorithm is enhanced to find one or more segments that are probably contained in the translated region of the gene and can be used as PCR primers to select appropriate clones in cDNA libraries by selective amplification. The algorithm is further extended to locate a set of PCR primers that uniformly cover all translated regions and can be used for RT-PCR and further sequencing of (unknown) mRNA.      

Role of activated cellular c-Ha-ras-1 oncogene in the mutagenic effect of the plasmid pEJ6.6]

The role of the activated oncogene c-Ha-ras-1 from human bladder carcinoma integrated into the pEJ6.6 plasmid in the mutagenic effect of the plasmid was studied in Chinese hamster cells. The frequency of hypoxanthine-phosphoribosyltransferase defective (HPRT-) mutants after treatment with pEJ6.6 containing an active c-Ha-ras-1 exceeded that in control dishes treated with a derivative of pEJ6.6 plasmid with an inactivated oncogene. The inactivation was achieved by introducing a deletion into the coding region of the oncogene. The mutagenic effect was rather weak but statistically significant. Thus, the data obtained show that the mutagenic activity of pEJ6.6 plasmid is determined by its oncogene. The role of mutagenic effects of activated cellular oncogenes in malignant transformation is discussed.