Design of a Wide Ranging Highly Sensitive Pressure Sensor Based on Two-Dimensional Photonic Crystals

Plasmonics - A highly sensitive pressure sensor operating over a wide pressure range based on two-dimensional photonic crystals having a Mach-Zehnder interferometer structure has been developed....     

Polyploidy does not control all: Lineage‐specific average chromosome length constrains genome size evolution in ferns

Recent studies investigating the evolution of genome size diversity in ferns have shown that they have a distinctive genome profile compared with other land plants. Ferns are typically characterized by possessing medium‐sized genomes, although a few lineages have evolved very large genomes. Ferns are different from other vascular plant lineages as they are the only group to show evidence for a correlation between genome size and chromosome number. In this study, we aim to explore whether the evolution of fern genome sizes is not only shaped by chromosome number changes arising from polyploidy but also by constraints on the average amount of DNA per chromosome. We selected the genus Asplenium L. as a model genus to study the question because of the unique combination of a highly conserved base chromosome number and a high frequency of polyploidy. New genome size data for Asplenium taxa were combined with existing data and analyzed within a phylogenetic framework. Genome size varied substantially between diploid species, resulting in overlapping genome sizes among diploid and tetraploid spleenworts. The observed additive pattern indicates the absence of genome downsizing following polyploidy. The genome size of diploids varied non‐randomly and we found evidence for clade‐specific trends towards larger or smaller genomes. The 578‐fold range of fern genome sizes have arisen not only from repeated cycles of polyploidy but also through clade‐specific constraints governing accumulation and/or elimination of DNA.     

Unwanted Horse Population in Illinois: Perceptions of Horse Owners,Non-Horse Owners,and Equine Industry Stakeholders

This paper presents the results of an investigation to determine perceptions, awareness, and knowledge of the unwanted horse population in Illinois from the viewpoint of horse owners, non-horse owners, and equine industry stakeholders. A questionnaire included items that pertained to knowledge of current legislation, equine background, current methods of controlling the unwanted horse population, and methods that respondents believe would reduce the unwanted horse population in Illinois. Results indicated that 58% of horse owners viewed horses as companion animals. Respondents perceived financial hardship to be the major reason why horses become unwanted. Current methods of managing unwanted horse populations were found to be ineffective. Reducing the costs of euthanasia and carcass disposal, allowing processing facilities to reopen in Illinois, and increasing the availability of gelding programs emerged as the most effective ways to manage the unwanted horse population. Results of this survey may lead to greater awareness of the unwanted horse population in Illinois. Furthermore, these results may lead to discussions about future legislation in the State designed to support and manage unwanted horses.     

Vibrational and electronic circular dichroism study of the interactions of cationic porphyrins with (dG-dC)10 and (dA-dT)10

The interactions of two different porphyrins, without axial ligands-5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin-Cu(II) tetrachloride (Cu(II)TMPyP) and with bulky meso substituents-5,10,15,20-tetrakis(N,N,N-trimethylanilinium-4-yl)porphyrin tetrachloride (TMAP), with (dG-dC)10 and (dA-dT)10 were studied by combination of vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectroscopy at different [oligonucleotide]/[porphyrin] ratios, where [oligonucleotide] and [porphyrin] are the concentrations of oligonucleotide per base-pair and porphyrin, respectively. The combination of VCD and ECD spectroscopy enables us to identify the types of interactions, and to specify the sites of interactions: The intercalative binding mode of Cu(II)TMPyP with (dG-dC)(10), which has been well described, was characterized by a new VCD "marker" and it was shown that the interaction of Cu(II)TMPyP with (dA-dT)10 via external binding to the phosphate backbone and major groove binding caused transition from the B to the non-B conformer. TMAP interacted with the major groove of (dG-dC)10, was semi-intercalated into (dA-dT)10, and caused significant variation in the structure of both oligonucleotides at the higher concentration of porphyrin. The spectroscopic techniques used in this study revealed that porphyrin binding with AT sequences caused substantial variation of the DNA structure. It was shown that VCD spectroscopy is an effective tool for the conformational studies of nucleic acid-porphyrin complexes in solution.     

Impact of an extruded nucleotide on cleavage activity and dynamic catalytic core conformation of the hepatitis delta virus ribozyme

The self-cleaving hepatitis delta virus (HDV) ribozyme is essential for the replication of HDV, a liver disease causing pathogen in humans. The catalytically critical nucleotide C75 of the ribozyme is buttressed by a trefoil turn pivoting around an extruded G76. In all available crystal structures, the conformation of G76 is restricted by stacking with G76 of a neighboring molecule. To test whether this crystal contact introduces a structural perturbation into the catalytic core, we have analyzed approximately 200 ns of molecular dynamics (MD) simulations. In the absence of crystal packing, the simulated G76 fluctuates between several conformations, including one wherein G76 establishes a perpendicular base quadruplet in the major groove of the adjacent P1 stem. Second-site mutagenesis experiments suggest that the identity of the nucleotide in position 76 (N76) indeed contributes to the catalytic activity of a trans-acting HDV ribozyme through its capacity for hydrogen bonding with P1. By contrast, in the cis-cleaving genomic ribozyme the functional relevance of N76 is less pronounced and not correlated with the P1 sequence. Terbium(III) footprinting and additional MD show that the activity differences between N76 mutants of this ribozyme are related instead to changes in average conformation and modified cross-correlations in the trefoil turn.     

B3LYP/6-311++G* * study of structure and spin-spin coupling constant in heparin disaccharide

Structures of heparin disaccharide have been analyzed by DFT using the B3LYP/6-311++G( * *) method. The optimized geometries of two forms of this disaccharide, differing in the conformation ((1)C(4) and (2)S(0)) of the IdoA2S residue, confirmed considerable influences of the sulfate and the carboxylate groups upon the pyranose ring geometries. The computed energies showed that disaccharide having the (1)C(4) form of the IdoA2S residue is more stable than that with the (2)S(0) form. Interatomic distances, bond and torsion angles showed that interconversion of the IdoA2S residue results in geometry changes in the GlcN,6S residue as well. Three-bond proton-proton and proton-carbon spin-spin coupling constants computed for both forms agree with the experimental data and indicate that only two chair forms contribute to the conformational equilibrium in disaccharide. Influences of the charged groups upon the magnitudes of spin-spin coupling constants are also discussed.     

Genetic analysis of autosomal and X-linked markers across a mouse hybrid zone

In this paper, we present results of the first comprehensive study of the introgression of both autosomal and sex-chromosome markers across the central European portion of the hybrid zone between two house mouse subspecies, Mus musculus musculus and M. m. domesticus. More than 1800 individuals sampled from 105 sites were analyzed with a set of allozyme loci (hopefully representing neutral or nearly neutral markers) and X-linked loci (which are assumed to be under selection). The zone center is best modeled as a single straight line independent of fine-scale local geographic or climatic conditions, being maintained by a balance between dispersal and selection against hybrids. The width (w) of the multilocus autosomal cline was estimated as 9.6 km whereas the estimate for the compound X-chromosome cline was about 4.6 km only. As the former estimate is comparable to that of the Danish portion of the zone (assumed to be much younger than the central European one), zone width does not appear to be related to its age. The strength (B) of the central barrier was estimated as about 20 km; with dispersal (sigma) of about 1 km/gen(1/2), this means effective selection (s*) is approximately 0.06-0.09 for autosomal loci and about 0.25 for X-linked loci. The number of loci under selection was estimated as N= 56-99 for autosomes and about 380 for X-linked loci. Finally, we highlight some potential pitfalls in hybrid zone analyses and in comparisons of different transects. We suggest that conclusions about parts of the mouse genome involved in reproductive isolation and speciation should be drawn with caution and that analytical approaches always providing some estimates should not be used without due care regarding the support or confidence of such estimates, especially if conclusions are based on the difference between these estimates. Finally, we recommend that analysis in two-dimensional space, dense sampling, and rigorous treatment of data, including inspection of likelihood profiles, are essential for hybrid zone studies.     

An arachidonic acid generation/export system involved in the regulation of cholesterol transport in mitochondria of steroidogenic cells

Recent studies demonstrated the importance of the mitochondrial ATP in the regulation of a novel long-chain fatty acid generation/export system in mitochondria of diabetic rat heart. In steroidogenic systems, mitochondrial ATP and intramitochondrial arachidonic acid (AA) generation are important for steroidogenesis. Here, we report that mitochondrial ATP is necessary for the generation and export of AA, steroid production and steroidogenic acute regulatory protein induction supported by cyclic 3'-5'-adenosine monophosphate in steroidogenic cells. These results demonstrate that ATP depletion affects AA export and provide new evidence of the existence of the fatty acid generation and export system involved in mitochondrial cholesterol transport.     

Third activity of Bordetella adenylate cyclase (AC) toxin-hemolysin. Membrane translocation of AC domain polypeptide promotes calcium influx into CD11b+ monocytes independently of the catalytic and hemolytic activities

The Bordetella adenylate cyclase toxin-hemolysin (CyaA) targets phagocytes expressing the alpha(M)beta2 integrin (CD11b/CD18), permeabilizes their membranes by forming small cation-selective pores, and delivers into cells a calmodulin-activated adenylate cyclase (AC) enzyme that dissipates cytosolic ATP into cAMP. We describe here a third activity of CyaA that yields elevation of cytosolic calcium concentration ([Ca2+]i) in target cells. The CyaA-mediated [Ca2+]i increase in CD11b+ J774A.1 monocytes was inhibited by extracellular La3+ ions but not by nifedipine, SK&F 96365, flunarizine, 2-aminoethyl diphenylborinate, or thapsigargin, suggesting that influx of Ca2+ into cells was not because of receptor signaling or opening of conventional calcium channels by cAMP. Compared with intact CyaA, a CyaA-AC- toxoid unable to generate cAMP promoted a faster, albeit transient, elevation of [Ca2+]i. This was not because of cell permeabilization by the CyaA hemolysin pores, because a mutant exhibiting a strongly enhanced pore-forming activity (CyaA-E509K/E516K), but unable to deliver the AC domain into cells, was also unable to elicit a [Ca2+]i increase. Further mutations interfering with AC translocation into cells, such as proline substitutions of glutamate residues 509 or 570 or deletion of the AC domain as such, reduced or ablated the [Ca2+]i-elevating capacity of CyaA. Moreover, structural alterations within the AC domain, because of insertion of various oligopeptides, differently modulated the kinetics and extent of Ca2+ influx elicited by the respective AC- toxoids. Hence, the translocating AC polypeptide itself appears to participate in formation of a novel type of membrane path for calcium ions, contributing to action of CyaA in an unexpected manner.