Transfection efficiency and cytotoxicity of polyethyleneimine-coated magnetic iron oxide nanoparticles in rooster sperm cells

Since the morphology of the rooster spermatozoa is different to other animal spermatozoa, the aim of the current study was to investigate the transfection efficiency and cytotoxicity of polyethyleneimine (PEI) coated magnetic iron oxide nanoparticles (MION) on these cells. Liposome/nucleic acid (NA) complexes and PEI-coated MION linked to the labeled oligonucleotides were used. Viability and percentage of exogenous nucleic acid uptake of spermatozoa were measured by flow cytometry analyses. The results showed a significant increase in exogenous nucleic acid uptake by rooster spermatozoa (P < 0.001) when treated with MION-NA complexes in comparison to liposome/NA. There were no significant differences between efficiency of lipid-based transfection agent and MION (P > 0.05) during short incubation period. MION with or without magnetic field, did not show significant cytotoxicity while the lipid-based transfection agent significantly decreased (P < 0.05) the viability of rooster spermatozoa. Results of this study showed that magnetofection and lipofection were both effective methods which increased exogenous nucleic acid uptake by rooster spermatozoa. However, the magnetofection method was more successful in maintaining the cell's survival than lipofection method.     

Exploring the interactions of a Tb(III)–quercetin complex with serum albumins (HSA and BSA): spectroscopic and molecular docking studies

Serum albumins (human serum albumin (HSA) and bovine serum albumin (BSA), two main circulatory proteins), are globular and monomeric macromolecules in plasma that transport many drugs and compounds. In the present study, we investigated the interactions of the Tb(III)–quercetin (Tb–QUE) complex with HSA and BSA using common spectroscopic techniques and a molecular docking study. Fluorescence data revealed that the inherent fluorescence emission of HSA and BSA was markedly quenched by the Tb–QUE complex through a static quenching mechanism, confirming stable complex formation (a ground‐state association) between albumins and Tb–QUE. Binding and thermodynamic parameters were obtained from the fluorescence spectra and the related equations at different temperatures under biological conditions. The binding constants (K_b) were calculated to be 0.8547 × 10³ M^?1 for HSA and 0.1363 × 10³ M^?1 for BSA at 298 K. Also, the number of binding sites (n) of the HSA/BSA–Tb–QUE systems was obtained to be approximately 1. Thermodynamic data calculations along with molecular docking results indicated that electrostatic interactions have a main role in the binding process of the Tb–QUE complex with HSA/BSA. Furthermore, molecular docking outputs revealed that the Tb–QUE complex has high affinity to bind to subdomain IIA of HSA and BSA. Binding distances (r) between HSA–Tb–QUE and BSA–Tb–QUE systems were also calculated using the Forster (fluorescence resonance energy transfer) method. It is expected that this study will provide a pathway for designing new compounds with multiple beneficial effects on human health from the phenolic compounds family such as the Tb–QUE complex.     

Terbium‐sensitized fluorescence method for the determination of deferasirox in biological fluids and tablet formulation

A novel, rapid and sensitive spectroflurimetric method was developed and validated for the determination of deferasirox in urine, serum and tablet samples based on sensitization of terbium fluorescence. The excitation and emission wavelengths were 328 and 545 nm, respectively. The optimum conditions for the determination of deferasirox were investigated considering the effects of various parameters. The method was quantitatively evaluated in terms of linearity, recovery, reproducibility and limit of detection. Under the optimal conditions, the fluorescence intensities were linear with the concentration of deferasirox in the range of 5 × 10^?9 to 5×10^?6 mol L^?1, with a detection limit of 1.5 × 10^?9 mol L^?1 and a relative standard deviation of 1.1–2.3%. Linearity, reproducibility, recovery and limit of detection made the method suitable for determination of deferasirox in urine, serum and tablets samples. Copyright © 2010 John Wiley & Sons, Ltd.     

Spectroscopic studies on the interaction of quercetin-terbium(III) complex with calf thymus DNA

The interaction of native calf thymus DNA (CT-DNA) with quercetin-terbium(III) [Q-Tb(III)] complex at physiological pH was monitored by UV absorption spectrophotometry, circular dichroism, fluorescence spectroscopy, and viscosimetric techniques. The complex displays binding properties to the CT-DNA and was found to interact with CT-DNA through outside binding, demonstrated by a hypochromic effect of Q-Tb(III) on the UV spectra of CT-DNA and the calculated association constants (K). Also, decrease in the specific viscosity of CT-DNA, decrease in the fluorescence intensity of Q-Tb(III) solutions in the presence of increasing amounts of CT-DNA, and detectable changes in the circular dichroism spectrum of CT-DNA are other evidences to indicate that Q-Tb(III) complex interact with CT-DNA through outside binding.     

Introducing Bacillus licheniformis as the causal agent of pistachio dieback in Iran

During 2004 and 2006 growing seasons some pistachio trees in Kerman province of Iran showed dieback symptoms. Initial symptoms were observed at the beginning of the growing season and they developed during two weeks after green tip stage, as shoot tips turned black and dieback occurred. During the growing season, the symptoms developed and vessel destruction was observed. If these stems were not pruned during winter, dieback developed in the spring. During the growing season affected pistachio samples were collected and surface disinfected with 0.01% mercury chloride. Pieces of affected vessels were grown on nutrient agar (NA) and incubated at 25°C for three-to-four days. Bacterial colonies with Bacillus characteristics were isolated and 15 representative strains were selected for further characterisation. The pathogenicity of selected strains was verified on 2–3 year-old pistachio seedlings using injection of bacterial suspension (10⁷ cfu p/ml) and control plants inoculated with distilled water; vessel destruction developed after 20 days, and bacterial causal agent was isolated from seedlings. No symptoms were observed in control plants. The strains were Gram positive, motile, with central spores and caused a hypersensitivity reaction (HR) on tobacco and geranium; they were positive for anaerobic growth, nitrate reduction, utilisation of citrate, VP test, urease, catalase, growth at pH 5.7, 7% NaCl and 45°C, acid production from arabinose, xylose, glucose and mannitol, and anaerobic fermentation of glucose. They could hydrolyze starch, aesculin, Tween 80 and gelatin but indole production was negative. Based on the characteristics of the isolated strains, they were identified as Bacillus licheniformis. This is the first report of Bacillus licheniformis as a causal agent of pistachio dieback.     

Relationship between γ‐interferon gene polymorphisms and susceptibility to brucellosis infection

Interferon‐gamma (IFN‐γ) is a pro‐inflammatory cytokine that plays a pivotal role in the defense mechanism against Brucella infection. It was hypothesized that the IFN‐γ in (+874 A/T in intron 1) TT and +5644 T/A, TT genotypes, which are reportedly associated with high IFN production, are associated with susceptibility to brucellosis in Iranian subjects. Genotyping of these IFN‐γ variants by an allele‐specific polymerase chain reaction method was performed in 281 subjects, comprising 153 patients with active brucellosis and 128 healthy controls. It was found that the +874 minor allele (A) and homozygote genotype (AA) were significantly more frequently present in brucellosis patients than in controls (OR = 2.588; 95% CI, 1.313–5.104; P = 0.006 for the AA genotype; OR = 1.575; 95% CI, 1.124–2.216; P = 0.010 for the A allele). However, the allelic and genotypic distribution of the IFN‐γ polymorphism at position UTR5644 A>T did not differ significantly between patients and controls (P > 0.05). The distribution of haplotypes in this study suggests that the T/A haplotype (+874/UTR5644), which was present more frequently in controls than in patients, may protect subjects against Brucella infection. It is suggested that IFN‐γ +874 AA genotype and A allele are risk factors for developing brucellosis infection in Iranian subjects.     

The antimicrobial potential of a new derivative of cathelicidin from <Emphasis Type="Italic">Bungarus fasciatus</Emphasis> against methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

Cathelicidins are a family of antimicrobial peptides which exhibit broad antimicrobial activities against antibiotic-resistant bacteria. Considering the progressive antibiotic resistance, cathelicidin is a candidate for use as an alternative approach to treat and overcome the challenge of antimicrobial resistance. Cathelicidin-BF (Cath-BF) is a short antimicrobial peptide, which was originally extracted from the venom of Bungarus fasciatus. Recent studies have reported that Cath-BF and some related derivatives exert strong antimicrobial and weak hemolytic properties. This study investigates the bactericidal and cytotoxic effects of Cath-BF and its analogs (Cath-A and Cath-B). Cath-A and Cath-B were designed to increase their net positive charge, to have more activity against methicillin resistant S. aureus (MRSA). The results of this study show that Cath-A, with a +17-net charge, has the most noteworthy antimicrobial activity against MRSA strains, with minimum inhibitory concentration (MIC) ranging between 32–128 μg/ml. The bacterial kinetic analysis by 1 × MIC concentration of each peptide shows that Cath-A neutralizes the clinical MRSA isolate for 60 min. The present data support the notion that increasing the positive net charge of antimicrobial peptides can increase their potential antimicrobial activity. Cath-A also displayed the weakest cytotoxicity effect against human umbilical vein endothelial and H9c2 rat cardiomyoblast cell lines. Analysis of the hemolytic activity reveals that all three peptides exhibit minor hemolytic activity against human erythrocytes at concentrations up to 250 μg/ml. Altogether, these results suggest that Cath-A and Cath-B are competent candidates as novel antimicrobial compounds against MRSA and possibly other multidrug resistant bacteria.     

Variations de la composition azotee de Pinus canariensis au cours de la germination

The study of the different nitrogen fractions of Pinus canariensis during seed germination and seedling development indicates a progressive hydrolysis of the insoluble fraction. Arginine is quantitatively one of the most important amino acids in seed proteins.