Overexpression of high molecular weight FGF-2 forms inhibits glioma growth by acting on cell-cycle progression and protein translation

In order to clarify the role of HMW FGF-2 in glioma development and angiogenesis, we over-expressed different human FGF-2 isoforms in C6 rat glioma cell line using a tetracycline-regulated expression system. Phenotypic modifications were analyzed in vitro and compared to untransfected cells or to cells over-expressing 18 kDa FGF-2 or all FGF-2 isoforms. In particular, we demonstrate that HMW FGF-2 has unique features in inhibiting glioma cell proliferation. HMW FGF-2 expressing cells showed a cell-cycle arrest at the G2M, demonstrating a role of HMW FGF-2 in controlling the entry in mitosis. Moreover, hydroxyurea was ineffective in blocking cells at the G1S boundary when HMW FGF-2 was expressed. We also show that the HMW FGF-2 isoforms inhibit 4E-BP1 phosphorylation at critical sites restoring the translation inhibitory activity of 4E-BP1. In vivo, inhibition of tumor growth was observed when cells expressed HMW FGF-2. This indicates that HMW FGF-2 inhibits tumor growth in glioma cells by acting on cell-cycle progression and protein translation.     

Myo2p, a class V myosin in budding yeast, associates with a large ribonucleic acid-protein complex that contains mRNAs and subunits of the RNA-processing body

Myo2p is an essential class V myosin in budding yeast with several identified functions in organelle trafficking and spindle orientation. The present study demonstrates that Myo2p is a component of a large RNA-containing complex (Myo2p-RNP) that is distinct from polysomes based on sedimentation analysis and lack of ribosomal subunits in the Myo2p-RNP. Microarray analysis of RNAs that coimmunoprecipitate with Myo2p revealed the presence of a large number of mRNAs in this complex. The Myo2p-RNA complex is in part composed of the RNA processing body (P-body) based on coprecipitation with P-body protein subunits and partial colocalization of Myo2p with P-bodies. P-body disassembly is delayed in the motor mutant, myo2-66, indicating that Myo2p may facilitate the release of mRNAs from the P-body.     

Targeting of β-Arrestin2 to the Centrosome and Primary Cilium: Role in Cell Proliferation Control

Background

The primary cilium is a sensory organelle generated from the centrosome in quiescent cells and found at the surface of most cell types, from where it controls important physiological processes. Specific sets of membrane proteins involved in sensing the extracellular milieu are concentrated within cilia, including G protein coupled receptors (GPCRs). Most GPCRs are regulated by β-arrestins, βarr1 and βarr2, which control both their signalling and endocytosis, suggesting that βarrs may also function at primary cilium.

Methodology/Principal Findings

In cycling cells, βarr2 was observed at the centrosome, at the proximal region of the centrioles, in a microtubule independent manner. However, βarr2 did not appear to be involved in classical centrosome-associated functions. In quiescent cells, both in vitro and in vivo, βarr2 was found at the basal body and axoneme of primary cilia. Interestingly, βarr2 was found to interact and colocalize with 14-3-3 proteins and Kif3A, two proteins known to be involved in ciliogenesis and intraciliary transport. In addition, as suggested for other centrosome or cilia-associated proteins, βarrs appear to control cell cycle progression. Indeed, cells lacking βarr2 were unable to properly respond to serum starvation and formed less primary cilia in these conditions.

Conclusions/Significance

Our results show that βarr2 is localized to the centrosome in cycling cells and to the primary cilium in quiescent cells, a feature shared with other proteins known to be involved in ciliogenesis or primary cilium function. Within cilia, βarr2 may participate in the signaling of cilia-associated GPCRs and, therefore, in the sensory functions of this cell “antenna”.     

Insertion sequences enrichment in extreme Red sea brine pool vent

Mobile genetic elements are major agents of genome diversification and evolution. Limited studies addressed their characteristics, including abundance, and role in extreme habitats. One of the rare natural habitats exposed to multiple-extreme conditions, including high temperature, salinity and concentration of heavy metals, are the Red Sea brine pools. We assessed the abundance and distribution of different mobile genetic elements in four Red Sea brine pools including the world’s largest known multiple-extreme deep-sea environment, the Red Sea Atlantis II Deep. We report a gradient in the abundance of mobile genetic elements, dramatically increasing in the harshest environment of the pool. Additionally, we identified a strong association between the abundance of insertion sequences and extreme conditions, being highest in the harshest and deepest layer of the Red Sea Atlantis II Deep. Our comparative analyses of mobile genetic elements in secluded, extreme and relatively non-extreme environments, suggest that insertion sequences predominantly contribute to polyextremophiles genome plasticity.

     

Naringenin alleviate reproductive toxicity evoked by lead acetate via attenuation of sperm profile and biochemical alterations in male Wistar rat: Involvement of TGFβ/AKT/mTOR pathway

Exposure to Lead -causes testicular dysfunction through oxidative stress, inflammation, and apoptosis; however, naringenin (NGN) therapeutic impact against lead-evoked testicular dysfunction remains elusive. Herein, the point of the study was to examine the defensive impact of NGN on testicular dysfunction initiated by lead. Seventy-Two male Wistar rats were allotted into nine groups; control group, drug control groups, lead acetate group, as well as NGN treated groups (10, 25, and 50 mg/kg) respectively, given 5 days before lead acetate treatment. The result showed clearly the impact of lead on reduced sperm count, sperm motility as well as serum testosterone and LH levels. Additionally, it caused a significant rise in testicular inflammatory markers TNF-α, IL-1β, and TGFβ, effects that were accompanied by a reduction of AKT and mTOR levels. Lead acetate also caused degenerative changes in the testis, atrophy, and loss of spermatogenic series. Our findings revealed that NGN in a dose-dependent manner improved spermiotoxicity induced by lead acetate via restoration of the testicular function, preservation of spermatogenesis, halting inflammatory cytokines along with the enhancement of germ cell survival using upregulation of AKT/mTOR expressions. The present study discloses that NGN suppresses lead acetate toxicity that is involved in the antioxidant effect in a dose-dependent manner, besides its anti-inflammatory property.     

Gene expression profiling identifies retinoids as potent inducers of macrophage lipid efflux

Vitamin A and its naturally occurring derivatives 9-cis retinoic acid (9-cis RA) and all-trans retinoic acid (ATRA) exert a variety of biological effects including immunomodulation, growth, differentiation, and apoptosis of normal and neoblastic cells. In order to directly study the effects of these retinoids on macrophage gene expression and lipid metabolism, primary human monocytes and in vitro differentiated macrophages were stimulated with beta-carotene, 9-cis RA, and ATRA and global gene expression profiles were analyzed by Affymetrix DNA-microarrays and differentially regulated genes were verified by quantitative TaqMan RT-PCR. Among others, we have identified a strong up-regulation of a cluster of genes involved in cholesterol metabolism including apolipoproteins (apoC-I, apoC-II, apoC-IV, apoE), the scavenger receptor CD36, steroid-27-hydroxylase (CYP27A1), liver X receptor alpha (LXRalpha), and ATP-binding cassette transporters A1 (ABCA1) and G1 (ABCG1). Since the CYP27A1 gene displayed the strongest up-regulation on the mRNA level, we cloned various deletion constructs of the promoter region and analyzed the response to retinoids in macrophages. Thereby, a novel retinoic acid-responsive element could be located within 191 bp of the proximal CYP27A1 promoter. To further assess the functional consequences of retinoid receptor action, we carried out phospholipid and cholesterol efflux assays. We observed a strong induction of apoA-I-dependent lipid efflux in stimulated macrophages, implicating an important role for retinoids in cellular functions of macrophages.     

Somatic Hybrids Between Potato and S. berthaultii Show Partial Resistance to Soil‐Borne Fungi and Potato Virus Y

Three tetraploid somatic hybrid lines produced by protoplast fusion between a dihaploid potato, Solanum tuberosum, cultivar BF15 and the wild potato species Solanum berthaultii were evaluated here for their response to different soil‐borne pathogens, that is Fusarium solani, Pythium aphanidermatum and Rhizoctonia solani as well as to infection by potato virus Y (PVY). Both hybrid and BF15 plants grown in vitro were inoculated with the tested pathogen strains, that is R. solani, P. aphanidermatum, or F. solani. The growth level and disease severity index of these plants were compared to the susceptible commercial cultivar Spunta. A better growth of inoculated hybrid plants and restricted disease symptoms were observed in comparison with the commercial plants. Under glasshouse conditions and after inoculation with R. solani and P. aphanidermatum, improved resistance of the hybrid plants to these pathogens was confirmed. Indeed, these plants showed no significant damage following inoculation and a better development in R. solani‐infected plants. The susceptibility of the hybrid tubers to R. solani, P. aphanidermatum, and to F. solani infection was also determined. A significant reduction of tissue colonisation was observed in all the hybrid lines compared to the cultivated cultivars. The STBc and STBd hybrids also showed improved resistance to the PVY ordinary strain (PVY^o) under glasshouse conditions.     

Endophytic bacteria from Datura metel for plant growth promotion and bioprotection against Fusarium wilt in tomato

Nine non-pathogenic bacterial isolates, recovered from Datura metel organs and able to colonise the internal stem tissues of tomato cultivar Rio Grande, were screened for their ability to suppress tomato Fusarium wilt disease caused by Fusarium oxysporum f. sp. lycopersici (FOL), and to enhance plant growth. S33 and S85 isolates tested were found to be the most effective in decreasing Fusarium wilt severity by 94–95% compared to FOL-inoculated and untreated control. A significant enhancement of growth parameters was recorded on tomato plants inoculated or not with FOL. Both isolates were characterised and identified using 16S rDNA sequencing genes as Stenotrophomonas sp. str. S33 (KR818084) and Pseudomonas sp. str. S85 (KR818087). Screened in vitro for their antifungal activity towards FOL, these isolates led to 38.7% and 22.5% decrease in pathogen radial growth and to the formation of an inhibition zone of 12.75 and 8.37?mm respectively. Stenotrophomonas sp. str. S33 and Pseudomonas sp. str. S85 were found to be chitinase-, protease- and pectinase-producing strains but unable to produce hydrogen cyanide. Production of indole-3-acetic acid-like compounds, phosphate solubilising ability and pectinase activity were investigated for elucidating their plant growth-promoting traits and their endophytic colonisation ability.     

pH-Dependent Solubility and Dissolution Behavior of Carvedilol—Case Example of a Weakly Basic BCS Class II Drug

The objective of this study was to investigate the pH-dependent solubility and dissolution of weakly basic Biopharmaceutical Classification Systems (BCS) class II drugs, characterized by low solubility and high permeability, using carvedilol, a weak base with a pK _a value of 7.8, as a model drug. A series of solubility and in vitro dissolution studies was carried out using media that simulate the gastric and intestinal fluids and cover the physiological pH range of the GI from 1.2 to 7.8. The effect of ionic strength, buffer capacity, and buffer species of the dissolution media on the solubility and dissolution behavior of carvedilol was also investigated. The study revealed that carvedilol exhibited a typical weak base pH-dependent solubility profile with a high solubility at low pH (545.1–2591.4 μg/mL within the pH range 1.2–5.0) and low solubility at high pH (5.8–51.9 μg/mL within the pH range 6.5–7.8). The dissolution behavior of carvedilol was consistent with the solubility results, where carvedilol release was complete (95.8–98.2% released within 60 min) in media simulating the gastric fluid (pH 1.2–5.0) and relatively low (15.9–86.2% released within 240 min) in media simulating the intestinal fluid (pH 6.5–7.8). It was found that the buffer species of the dissolution media may influence the solubility and consequently the percentage of carvedilol released by forming carvedilol salts of varying solubilities. Carvedilol solubility and dissolution decreased with increasing ionic strength, while lowering the buffer capacity resulted in a decrease in carvedilol solubility and dissolution rate.