Characterization of Zwitterionic Phosphatidylcholine-Based Bilayer Vesicles as Efficient Self-Assembled Virus-Like Gene Carriers

Entrapment of plasmid DNA (pDNA) in an aqueous compartment separated from the bulk external aqueous medium by a phospholipid bilayer resembles a structure similar to a primitive living cell, and interestingly, this phenomenon occurs completely self-assembled. Being inspired by such a structure as well as using the dehydration–rehydration technique, we were able to encapsulate pDNA without using multivalent cations and with high efficiency (98 %) into noncationic lipid bilayer vesicles. These liposomes which were composed of dimyristoyl-sn-glycero-3-phosphocholine unlike cationic liposomes, were nontoxic. The obtained liposome structure was able protect DNA against nuclease and was completely stable, in a way that even after 6 months, it still kept the pDNA in its structure, and there was a small change in its size (100–150 nm) determined by dynamic light scattering. The purpose of this research is to polarize the researchers’ interest toward utilization of neutral liposomes originating from the cell membrane as the most efficient carrier for gene delivery. We indicated that in using such carriers, which are the most similar synthetic structures to viruses, their inability in electrostatic interaction with DNA would not be an obstacle for entrapping nucleic acids.     

Transformation and evaluation of different transgenic lines for Glyphosate tolerance and cane borer resistance genes in sugarcane (<Emphasis Type="Italic">Saccharum officinarum</Emphasis> L.)

The aim of this study was to ensure the systematic protein expression of two genes (GTG and Cry1Ac) under the influence of two different constitutive promoters i.e. Ubiquitin-1 and CaMV 35S promoters in different sugarcane lines. PCR amplification of GTG and Cry1Ac was achieved from putative transgenic plants through gene specific primers. Qualitative comparisons of GTG and Cry1Ac genes expression under two different promoters were obtained through protein dot blot and dipstick assay. The appearance of comparatively dark color dots in dot blot and dark color bands on dipstick with Ubiquitin as compared to light color bands with CaMV35S promoter, qualitatively confirmed high protein expression of two genes under Ubiquitin promoter. In quantitative gene expression comparisons maximum optical density (OD) at 450 nm of UV-light was obtained for GTG (3.7 OD) and Cry1Ac (3 OD) under Ubiquitin promoter, while for GTG (1.6 OD) and Cry1Ac (2.5 OD) with CaMV 35S promoter. The results indicated higher expression of two genes under Ubiquitin-1 promoter in sugarcane was found as compared to CaMV 35S promoter. This study provides a guide for stable and high expression of transgenes with reference to Ubiquitin-1 promoter which can be utilize in sugarcane as well as in other monocots.     

Elevated atmospheric [CO2] stimulates sugar accumulation and cellulose degradation rates of rice straw

Rice straw can serve as potential material for bioenergy production. However, the quantitative effects of increasing atmospheric carbon dioxide concentration [CO₂] on rice straw quality and the resulting consequences for bioenergy utilization are largely unknown. In this study, two rice varieties, WYJ and LY, that have been shown previously to have a weak and strong stimulatory response to rising [CO₂], respectively, were grown with and without additional CO₂ at China free‐air carbon dioxide enrichment (FACE) platform. Qualitative and quantitative measurements in response to [CO₂] included straw biomass (including leaf, sheath, and stem), the concentration of nonstructural and structural carbohydrates, the syringyl‐to‐guaiacyl (S/G) ratio of lignin, glucose and xylose release from structural carbohydrate, total sugar release by enzymatic saccharification, and sugar yield and the ratio of cellulose and hemicellulose degradation. Elevated [CO₂] significantly increased straw biomass and nonstructural carbohydrate contents while enhancing the degraded ratio of structural carbohydrates as indicated by the decreased lignin content and increased S/G ratio. Overall, total sugar yield (g m^?2) in rice straw significantly increased by 27.1 and 57% for WYJ and LY at elevated [CO₂], respectively. These findings, while preliminary, suggest that rice straw quality and potential biofuel utilization may improve as a function of rising [CO₂].     

Randomized Prospective Comparison of Two Protocols for Head-up Tilt Testing in Patients with Normal Heart and Recurrent Unexplained Syncope

BackgroundThis randomized study was aimed to compare the diagnostic value of two head-up tilt testing protocols using sublingual nitroglycerin for provocation in patients with recurrent unexplained syncope and normal heart.MethodsThe patients with normal findings in physical examination, electrocardiography and echocardiography were randomly submitted to one of upright tilt test protocols. The only difference between two protocols was that nitroglycerin was administered after a five minute resting phase in supine position during protocol B. We also considered eighty normal persons as the control group.ResultsOut of 290 patients that underwent tilt testing, 132 patients were in group A versus 158 patients in group B. Both groups had an identical distribution of clinical characteristics. Tilt test was positive in 79 patients in group A (25 in passive phase, 54 in active phase) versus 96 patients in group B (43 in passive phase, 53 in active phase). There was no significant difference between results in two groups (P value = 0.127). Forty cases were tested with protocol A and forty underwent tilt testing with protocol B. Tilt test was positive in 4 cases with protocol A versus 3 cases in protocol B. The positive rates of tilt testing with protocol A was 60% while it was 61% in protocol B. The specificity of testing with protocol A was 90% and it was 92.5% in protocol B.ConclusionsAccording to our data, adding a period of rest and returning to supine position before nitroglycerin administration had no additional diagnostic yield.     

Impact of microencapsulated peptidase (Aspergillus oryzae) on cheddar cheese proteolysis and its biologically active peptide profile

We investigated the delivery of calcium-alginate encapsulated peptidase (Flavourzyme(?), Aspergillus oryzae) on proteolysis of Cheddar cheese. Physical and chemical characteristics such as moisture, pH and fat content were measured, and no differences were found between control and experimental cheese at day 0. SDS-PAGE analysis clearly showed that proteolysis of α and k casein was significantly accelerated after three months of maturity in the experimental cheese. A large number of low molecular weight peptides were found in the water soluble fraction of the experimental cheeses and some of these peptides were new. N-terminal amino acid sequence analysis identified these as P(1), Leu-Thu-Glu; P(3), Asp-Val-Pro-Ser-Glu) and relatively abundant stable peptides P(2), P(4), Arg-Pro-Lys-His-Pro-Ile; P(5), Arg-Pro-Lys-His-Pro-Ile-Lys and P(6). These peptides were mainly originated from αs1-CN and β-CN. Three of the identified peptides (P(1), P(2), P(3) and P(4)) are known to biologically active and P(1) and P(3) were only present in experimental cheese suggesting that experimental cheese has improved health benefits.     

Simultaneous Treatment of Dioxins and Heavy Metals in Tagonoura Harbor Sediment by Two-Step Pyrolysis

This paper describes the simultaneous treatment of PCDD/PCDF and toxic heavy metals contaminated sediment by pyrolysis with emphasis on complete removal and destruction of PCDD/PCDF in Tagonoura harbor sediment during a two-step pyrolysis process. Pyrolysis was conducted at different temperatures and N ₂ gas flow rates. Results showed that almost all PCDD/PCDF (99.998%) can be removed from the sediment by treatment at 800°C for 30 minutes in single-step pyrolysis; however, PCDD/PCDF remained in the gas phase without destruction. Analysis also revealed that some PCDD/PCDF formation occurred during the single-step pyrolysis. However, by the use of two-step pyrolysis, where off-gases from the first furnace are heated at 1000°C, PCDD/PCDF in the final gas effluent was dramatically reduced by a thermal degradation mechanism. Stabilization of toxic heavy metals was also observed. Specifically, their leaching activity drastically decreased with increasing pyrolysis temperature. Significant metal volatilization did not occur. Though the low temperature pyrolysis was effective in removing PCDD/PCDF, the leachability of toxic heavy metals such as Cr and Ni was higher that of 800°C; however, lower than untreated. Two-step pyrolysis at 800°C for 30 minutes in the single-step and 1000°C in the two-step pyrolyzer would be effective for the treatment of sediments contaminated with PCDD/PCDF, toxic heavy metals and organic matters simultaneously.     

Cloning,Sequencing, Expression and Structural Investigation of Mnemiopsin from <Emphasis Type="Italic">Mnemiopsis leidyi</Emphasis>: An Attempt Toward Understanding Ca<Superscript>2+</Superscript>-Regulated Photoproteins

A comparison of the two most famous groups of calcium-regulated photoproteins, cnidarians and ctenophores, showed unexpectedly high degree of structural similarity regardless of their low sequence identity. It was suggested these photoproteins can play an important role in understanding the structural basis of bioluminescence activity. Based on this postulate, in this study the cDNA of mnemiopsin from luminous ctenophore Mnemiopsis leidyi was cloned, expressed, purified and sequenced. The purified cDNA, with 621 base pairs, coded a 206 residues protein. Sequence of mnemiopsin showed 93.5 and 51% similarity to other ctenophore proteins and cnidarians, respectively. The cDNA encoding apo-mnemiopsin of M. leidyi was expressed in Escherichia coli. The purified apo-protein showed a single band on SDS-PAGE (molecular weight ~27 kDa). A semi-synthetic mnemiopsin was prepared using coelenterazine and EDTA and its luminescence activity was measured in the presence of CaCl₂. The results showed an optimum pH of 9.0 and lower calcium sensitivity compared to aequorin. Comparison of amino acid residues in substrate binding site indicated that binding pocket of ctenophores contains less aromatic residues than cnidarians. This can lead to a decline in the number of stacking interactions between substrate and protein which can affect the stability of coelenterazine in binding cavity. Structural comparison of photoproteins with low sequence identity and high 3D structural similarity, can present a new insight into the mechanism of light emission in photoproteins.     

Morphometric study and sexual dimorphism analyses in an Iranian population of Scorpio maurus (Arachnida: Scorpionidae)

Natural selection and sexual selection are cardinal factors in shaping the body of animals such as scorpions. Scorpio maurus (Scorpiones: Scorpionidae) has a worldwide distribution. Sexual dimorphism has been reported from this species in a study in Egypt. Morphometry is used to determine the sexual dimorphism between the two sexes. In the current study, scorpions were collected from six locations of the southern and northern provinces of Fars, Iran. In this study, 53 morphological characters of 15 specimens of each sex of Scorpio maurus were studied based on statistical analyses; however, dimorphism was only observed in 21 morphological characters, including chelicerae and carapace length, pedipalp characters, width of the second segment of metasoma, telson and pectin length, number of left pectin teeth, and some of the leg''s segments. It means that these characters are in the control of sexual and natural selection. This study was performed for the first time on Scorpio maurus species in Iran.     

Recycling factors for ribosome disassembly in the apicoplast and mitochondrion of Plasmodium falciparum

The reduced genomes of the apicoplast and mitochondrion of the malaria parasite Plasmodium falciparum are actively translated and antibiotic‐mediated translation inhibition is detrimental to parasite survival. In order to understand recycling of organellar ribosomes, a critical step in protein translation, we identified ribosome recycling factors (RRF) encoded by the parasite nuclear genome. Targeting of PfRRF1 and PfRRF2 to the apicoplast and mitochondrion respectively was established by localization of leader sequence–GFP fusions. Unlike any RRF characterized thus far, PfRRF2 formed dimers with disulphide interaction(s) and additionally localized in the cytoplasm, thus suggesting adjunct functions for the factor. PfRRF1 carries a large 108‐amino‐acid insertion in the functionally critical hinge region between the head and tail domains of the protein, yet complemented Escherichia coli RRF in the LJ14frr^ts mutant and disassembled surrogate E. coli 70S ribosomes in the presence of apicoplast‐targeted EF‐G. Recombinant PfRRF2 bound E. coli ribosomes and could split monosomes in the presence of the relevant mitochondrial EF‐G but failed to complement the LJ14frr^ts mutant. Although proteins comprising subunits of P. falciparum organellar ribosomes are predicted to differ from bacterial and mitoribosomal counterparts, our results indicate that the essential interactions required for recycling are conserved in parasite organelles.