Extraction & Spectrophotometric Determination of Rhenium with Thiocyanate & Hydroxamic Acids

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Interbody Fusion in Low Grade Lumbar Spondylolsithesis: Clinical Outcome Does Not Correalte with Slip Reduction and Neural Foraminal Dimension

Study DesignProspective nonrandomized study.PurposeTo find a possible correlation between clinical outcome and extent of lumbar spondylolisthesis reduction.Overview of LiteratureThere is no consensus in the literature concerning whether a beneficial effect of reduction on outcome can be expected following reduction and surgical fusion for low grade lumbar spondylolisthesis.MethodsForty six patients with a mean age of 37.5 years (age, 17–48 years) with isthmic spondylolisthesis underwent interbody fusion with cages with posterior instrumentation (TLIF). Clinical outcome was measured using visual analogue score (VAS) and Oswestry disability index (ODI). Foraminal dimensions and disc heights were measured in standard digital radiographs. These were analyzed at baseline and 1 year after surgery and changes were compared. Radiographic fusion was judged with computed tomography scans at 1 year.ResultsNinety percent of the patients had good or very good clinical results with fusion and instrumentation. Baseline and one-year postoperative mean VAS score was 6.33 (range, 5–8) and 0.76 (range, 0–3), respectively (p=0.004). Baseline and one-year postoperative, mean ODI score was 48 (range, 32–62) and 10 (range, 6–16), respectively (p<0.001). A mean spondylolisthesis slip of 32.1% was reduced to 6.7% at 1 year. Average anterior disc height, posterior disc height, vertical foraminal dimension), and foraminal) diameter improved from 9.8 to 11.7 mm (p=0.005), 4.5 to 5.8 mm (p=0.004), 11.3 to 12.6 mm (p=0.002), and 18.6 to 20.0 mm (p<0.001), respectively. The fusion rate was 75% with TLIF. There is no significant correlation between the improvements of ODI scores and the extent of slip reduction.ConclusionsNeural decompression and interbody fusion can significantly improve pain and disability but the clinical outcome does not correlate with radiological improvement in the neural foraminal dimension

Features of 80S mammalian ribosome and its subunits

It is generally believed that basic features of ribosomal functions are universally valid, but a systematic test still stands out for higher eukaryotic 80S ribosomes. Here we report: (i) differences in tRNA and mRNA binding capabilities of eukaryotic and bacterial ribosomes and their subunits. Eukaryotic 40S subunits bind mRNA exclusively in the presence of cognate tRNA, whereas bacterial 30S do bind mRNA already in the absence of tRNA. 80S ribosomes bind mRNA efficiently in the absence of tRNA. In contrast, bacterial 70S interact with mRNA more productively in the presence rather than in the absence of tRNA. (ii) States of initiation (Pi), pre-translocation (PRE) and post-translocation (POST) of the ribosome were checked and no significant functional differences to the prokaryotic counterpart were observed including the reciprocal linkage between A and E sites. (iii) Eukaryotic ribosomes bind tetracycline with an affinity 15 times lower than that of bacterial ribosomes (Kd 30 μM and 1–2 μM, respectively). The drug does not effect enzymatic A-site occupation of 80S ribosomes in contrast to non-enzymatic tRNA binding to the A-site. Both observations explain the relative resistance of eukaryotic ribosomes to this antibiotic

Characterization of Yeast Extracellular Vesicles: Evidence for the Participation of Different Pathways of Cellular Traffic in Vesicle Biogenesis

Background: Extracellular vesicles in yeast cells are involved in the molecular traffic across the cell wall. In yeast pathogens, these vesicles have been implicated in the transport of proteins, lipids, polysaccharide and pigments to the extracellular space. Cellular pathways required for the biogenesis of yeast extracellular vesicles are largely unknown. Methodology/Principal Findings: We characterized extracellular vesicle production in wild type (WT) and mutant strains of the model yeast Saccharomyces cerevisiae using transmission electron microscopy in combination with light scattering analysis, lipid extraction and proteomics. WT cells and mutants with defective expression of Sec4p, a secretory vesicleassociated Rab GTPase essential for Golgi-derived exocytosis, or Snf7p, which is involved in multivesicular body (MVB) formation, were analyzed in parallel. Bilayered vesicles with diameters at the 100–300 nm range were found in extracellular fractions from yeast cultures. Proteomic analysis of vesicular fractions from the cells aforementioned and additional mutants with defects in conventional secretion pathways (sec1-1, fusion of Golgi-derived exocytic vesicles with the plasm

A rare leucine codon in adpA is implicated in the morphological defect of bldA mutants of Streptomyces coelicolor

Streptomycetes are mycelial bacteria that produce sporulating aerial hyphae on solid media. Bald (bld) mutants fail to form aerial mycelium under at least some conditions. bldA encodes the only tRNA species able to read the leucine codon UUA efficiently, implying the involvement of a TTA-containing gene in initiating aerial growth. One candidate for such a gene was bldH, because the bldH109 mutant of Streptomyces coelicolor resembles bldA mutants in some aspects. In the work reported here, adpAc, an S. coelicolor gene similar to the Streptomyces griseus A factor-regulated adpAg, was found to complement the bldH109 mutant partially at both single and multiple copies. The sequence of adpAc from the bldH109 mutant revealed a frameshift. A constructed in frame deletion of adpAc conferred a bald colony phenotype, and the mutant behaved like bldA mutants and bldH109 in its pattern of extracellular signal exchange. Both adpAc and adpAg contain a TTA codon. A TTA-free version of adpAc was engineered by replacing the TTA leucine codon with a cognate TTG leucine codon. The adpA(TTA→TTG) gene could partially restore aerial mycelium formation to a bldA mutant when it was followed in cis by the gene ornA, as in the natural chromosomal arrangement. This indicated that the UUA codon in adpAc mRNA is the principal target through which bldA influences morphological differentiation. It also implied that translational arrest at the UUA codon in adpAc mRNA caused a polar effect on the downstream ornA, and that the poor translation of both genes contributes extensively to the deficiency of aerial mycelium formation in bldA mutants. Unlike the situation in S. griseus, adpAc transcription does not depend on the host’s γ-butyrolactone signalling system, at least in liquid cultures. In addition, sigma factor BldN, which is the homologue of an S. griseus sigma factor AdsA that is absent from adpAg mutants of S. griseus, was present in the constructed adpAc null mutant of S. coelicolor

Effect of sodium bisulfite modification on the arginine acceptance of E. coli tRNA Arg.

Escherichia coli tRNA Arg was treated with sodium bisulfite to convert exposed cytosine residues to uracil. This treatment resulted in the loss of amino acid acceptance of the tRNA Arg with pseudo first-order reaction kinetics. The active and inactive molecules were separated after about 60e active and inactive molecules were separated after about 60 percent inactivation and analyzed for U in various positions by finger-printing of the oligonucleotides produced by nucleases. The results show that C to U base transitions in the dihydrouridine loop and in the CCA terminus have no effect on the aminoacylation of this tRNA. Deamination of a cytosine residue at the second position of the anticodon resulted in the loss of amino acid acceptor activity of arginine transfer RNA

Discrimination between initiation and elongation of protein biosynthesis in yeast: identity assured by a nucleotide modification in the initiator tRNA.

Cytoplasmic initiator tRNAs from plants and fungi possess an unique 2'-phosphoribosyl residue at position 64 of their sequence. In yeast tRNA(iMet), this modified nucleotide located in the T-stem of the tRNA is a 2'-1''-(beta-O-ribofuranosyl-5''-phosphoryl)-adenosine. The phosphoribosyl residue of this modified nucleoside was removed chemically by treatment involving periodate oxidation of tRNA(iMet) and regeneration of the 3'-terminal adenosine with ATP (CTP):tRNA nucleotidyl transferase. The role of phosphoribosylation at position 64 for interaction with elongation factor eEF-1 alpha and initiation factor 2 (eIF-2) was investigated in the homologous yeast system. Whereas the 5'-phosphoribosyl residue prevents the binding of Met-tRNA(iMet) to eEF-1 alpha, it does not influence the interaction with eIF-2. After removal of the ribosyl group, the demodified initiator tRNA showed binding to eEF-1 alpha, but no change was detected with respect to the interaction with the initiation factor eIF-2. This observation is interpreted to mean that a single modification of an eucaryotic initiator tRNA in yeast serves as a negative discriminant for eEF-1 alpha, thus preventing the initiator tRNA(iMet) from entering the elongation cycle of protein biosynthesis

Fluorescence spectral studies of the substituted azobenzenes in different solvents

1165-1168Absorption and emission spectra of 2-carboxy-2'-hydroxy-5'-methylazobenzene (MAB) and 2-carboxy-2'-hydroxy-5'-methoxyazobenzene (MeAB) have been studied in different solvents like dimethylsulphoxide, acetonitrile, dimethylformamide and 2-butanol. The dissociation constants of the two substituted azodyes in their ground and excited states have been also determined