Insights into the structural stability of nuclear matrix ribonucleoprotein,LMG160: thermodynamic and spectroscopic analysis

Low-mobility group nonhistone chromatin protein, LMG_160, is a nuclear matrix ribonucleoprotein particle (RNP) which has a RNA molecule with approximately 300 bases. In this study, structural stability of the intact LMG₁₆₀ (I-LMG₁₆₀) was investigated at different ionic strength and in the absence of its RNA moiety (T-LMG₁₆₀) employing spectroscopic and thermodynamic techniques. The UV absorption spectra showed hypochromicity and red shift under increasing ionic strength for both forms of LMG₁₆₀ but in different extents. The fluorescence emission intensity was decreased as ionic strength was increased and the Stern–Volmer quenching constant (K_sv) for T-LMG₁₆₀ was 3.7 times less than for I-LMG₁₆₀. In the absence of sodium chloride, I-LMG₁₆₀ exhibited a very stable structure against the temperature change compared to T-LMG₁₆₀. The thermodynamic parameters showed that the positive values of ΔH_m and ΔS_m increased by increasing ionic strength in both forms of LMG₁₆₀. Removal of the RNA moiety altered secondary structure: as T-LMG₁₆₀ showed more helical content than I-LMG₁₆₀. From the results, it is concluded that I-LMG₁₆₀ is more sensitive to alteration of environment and the RNA has an important role in this RNP conformation. Also, interaction of both I- and T-LMG₁₆₀ with sodium chloride is entropy driven and is usually accompanied by surface hydrophobicity.     

A comparison study of the interaction between β-lactoglobulin and retinol at two different conditions: spectroscopic and molecular modeling approaches

The interaction between bovin β-Lactoglobulin (β-LG) and retinol at two different pH values was investigated by multispectroscopic, zeta potential, molecular modeling, and conductometry measurements. The steady state and polarization fluorescence spectroscopy revealed that complex formation at two different pH values could occur through a remarkable static quenching. According to fluorescence quenching, one set of binding site at pH 2 and two sets of binding sites at pH 7 were introduced for binding of retinol to β-LG that show the enhancement of saturation score of β-LG to retinol in dimmer condition. The polarization fluorescence analysis represented that there is more affinity between β-LG and retinol at pH 7 rather than at pH 2. The effect of retinol on β-LG was studied by UV-visible, circular dichroism (CD), and synchronous fluorescence, which indicated that retinol induced more structural changes on β-LG at pH 7. β-LG–retinol complex formation at two different pH values was recorded via applying resonance light scattering (RLS) and zeta potential. Conductometry and RLS showed two different behaviors of interaction between β-LG and retinol at two different pH values; therefore, dimmer formation played important roles in different behaviors of interaction between β-LG and retinol. The zeta potential was the implied combination of electrostatic and hydrophobic forces which are involved in β-LG–retinol complex at two different pH values, and the hydrophobic interactions play a dominant role in complex formation. Molecular modeling was approved by all experimental results. The acquired results suggested that monomer and dimmer states of β-LG can be induced by retinol with different behaviors.     

Effects of Zinc Supplement on Plasma Homocysteine Level in End-Stage Renal Disease Patients: a Double-Blind Randomized Clinical Trial

Increased homocysteine (hCys) level is an independent risk factor for cardiovascular complications in end-stage renal disease (ESRD) patients. The aim of this study was to evaluate effect of zinc (Zn) supplement on serum hCys level in ESRD patients. One hundred ESRD patients with Zn deficiency were enrolled in this double-blind randomized clinical trial. They were randomly subdivided into two groups and supplemented with Zn (Zn group) or placebo (control group) for 6 weeks. Fasting plasma hCys and Zn levels were measured before and at 43rd days after the start of the study. Serum Zn levels increased significantly (p?<?0.0001), in Zn-treated group in comparison to placebo-treated group. In the Zn-treated group, serum hCys levels reduced significantly (p?<?0.0001), compared to placebo group (p?>?0.05). There was a significant (p?<?0.0001) reduction of mean percentage of hCys in Zn-treated group compared to the placebo group. Our study showed that Zn supplementation decreases serum hCys levels in ESRD patients with Zn deficiency.     

Carbon Nanotube-Encapsulated Drug Penetration Through the Cell Membrane: An Investigation Based on Steered Molecular Dynamics Simulation

Understanding the penetration mechanisms of carbon nanotube (CNTs)-encapsulated drugs through the phospholipid bilayer cell membrane is an important issue for the development of intracellular drug delivery systems. In the present work, steered molecular dynamics (SMD) simulation was used to explore the possibility of penetration of a polar drug, paclitaxel (PTX), encapsulated inside the CNT, through a dipalmitoylphosphatidylcholine bilayer membrane. The interactions between PTX and CNT and between PTX and the confined water molecules inside the CNT had a significant effect on the penetration process of PTX. The results reveal that the presence of a PTX molecule increases the magnitude of the pulling force. The effect of pulling velocity on the penetration mechanism was also investigated by a series of SMD simulations, and it is shown that the pulling velocity had a significant effect on pulling force and the interaction between lipid bilayer and drug molecule.     

Efficiency of direct and indirect shoot organogenesis in different genotypes of Rosa hybrida

To optimize indirect regeneration (IR) and direct regeneration (DR) in Rosa hybrida cv. Apollo different explant types and different concentrations of plant growth regulators were investigated. Among the different auxins studied and over all explant types, 10???M 2,4-dichlorophenoxyacetic acid (2,4-D) promoted the highest frequency of callus production for IR. The highest frequency of regeneration (60.8?%) was obtained when calli were transferred to Murashige and Skoog medium supplemented with 2.5???M thidiazuron (TDZ) and 2???M gibberellic acid. The highest frequency of regeneration (80.2?%) for DR was obtained from leaves cultured on the medium containing 10???M TDZ. The efficiency of IR and DR were compared in four different rose cultivars including ??Apollo??, ??Black Baccara??, ??Maroussia?? and ??Amanda??. The frequency of regeneration in all four cultivars was significantly higher in DR compared to IR. Also shoots regenerated by DR appeared earlier than the shoots regenerated by IR. The results of flow cytometry showed that the shoots derived from IR to DR were tetraploid like the original cultivars.     

Two philometrids (Nematoda: Philometridae) infecting the tigertooth croaker Otolithes ruber (Bloch & Schneider) (Teleostei: Sciaenidae) off Iran, including erection of a new genus

Two philometrid nematodes (Philometridae) are described from the marine perciform fish (tigertooth croaker) Otolithes ruber (Bloch & Schneider) (Sciaenidae) from off Iran: Clavinemoides annulatus n. g., n. sp. based on female specimens from the caudal fin of fish from the Persian Gulf and Philometra otolithi Moravec & Manoharan, 2013 from subgravid and nongravid females collected from the ovary of fishes in the Sea of Oman and the Persian Gulf. The monotypic genus Clavinemoides n. g. is mainly characterised by a triangular oral aperture, a markedly large anterior oesophageal bulb, a distinctly annulated body and numerous fine elevated transverse cuticular bands. The finding of P. otolithi in Iranian waters represents a new geographical record of this parasite species. An updated key to the genera of the Philometrinae Baylis & Daubney, 1926 is provided.     

Evaluation of the effects of weak and moderate static magnetic fields on the characteristics of human low density lipoprotein in vitro

It has been suggested that exposure to electromagnetic fields may be a risk factor for cardiovascular disease in humans. Low density lipoprotein (LDL) modifications such as peroxidation and aggregation have been implicated in the pathogenesis of atherosclerosis. The present study investigated the effects of weak (0.125–0.5 mT) and moderate (1–4 mT) static magnetic fields (SMFs) on LDL oxidation, aggregation and zeta potential in vitro. Our results demonstrated that magnetic flux densities of 0.25 and 0.5 mT decreased, and magnetic flux densities of 3 and 4 mT increased the zeta potential and LDL oxidation in comparison with the control samples. All doses of SMFs increased the LDL aggregation in a time‐ and dose‐dependent manner. It is concluded that SMFs can alter the susceptibility of LDL to oxidation and this alteration is dependent on the applied magnetic flux density. The SMF, in addition to its role in the production and stabilization of free radicals and promotion of lipid peroxidation, may influence the metabolism of lipoproteins and their interaction with other molecules such as apolipoproteins, enzymes and receptors through the alteration of the LDL zeta potential and its particles tendency to aggregation. Bioelectromagnetics 34:397–404, 2013. © 2012 Wiley Periodicals, Inc.     

The removal of ρ-chlorophenol in aqueous cultures with free and alginate-immobilized cells of the microalga Tetraselmis suecica

The present study aimed at evaluating the ability of some isolated cyanobacterial and microalgal strains for the removal of ρ-chlorophenol (ρ-CP), an environmentally harmful contaminant. To identify the most efficient species, a screening program was carried out using 15 microalgal and cyanobacterial strains. Among them, Tetraselmis suecica was able to remove 67 % of the ρ-chlorophenol at an initial concentration of 20 mg L^?1 from the medium within a 10-day period. The efficacy of the process was dependent on the ρ-chlorophenol concentration. At concentrations above 60 mg L^?1 of the pollutant, no removal was observed due to the inhibitory effect of ρ-chlorophenol on the T. suecica cells. The effect of cell immobilization in alginate beads on T. suecica removal capacity was also examined. Using this technique, the removal efficacy for the initial ρ-CP concentration of 20 mg L^?1 increased up to 94 %.     

Alteration in genes expression patterns during in vitro differentiation of mouse spermatogonial cells into neuroepithelial-like cells

Pluripotent stem cells derived from testis is a new, natural, and unlimited source for cell therapy in regenerative medicine and represent a possible alternative to replacing of all cells in the body. Here, we designed a simple co-culture system of spermatogonia cells with Sertoli cells for the generation of embryonic stem-like cells from mouse testis. The importance of our simple method will be clear when we compared it with other complex and time-consuming methods. Embryonic stem-like colonies with sharp border confirmed by real-time PCR, immunocytochemistry and flow cytometry assessments. Embryonic stem-like colonies were immunopositive for pluripotency markers. Transition of spermatogonia cells to embryonic stem-like cells was accompanied by extensive changes in gene expression. These changes included significant increase in pluripotency genes expression and significant decrease in germ cell-specific genes expression. Also, we proved the differentiation capacity of embryonic stem-like cells to neuroepithelial-like cells which were immunoreactive to Nestin and Neurofilament 68. Evaluation of genes expression during in vitro differentiation into neuroepithelial-like cells showed high-level expression of Nestin whether this gene approximately has no expression in undifferentiated embryonic stem-like cells. Also, expression of pluripotency genes has significantly decreased in neuroepithelial-like cells compared with embryonic stem-like cells. This study shows that embryonic stem-like cells derived from testis are capable to differentiate into neuroepithelial-like cells that may provide a cellular reservoir usable for neurodegenerative disorders.