Effect of Heavy Metal Contaminated Shooting Range Soils on Mycorrhizal Colonization of Roots and Metal Uptake by Leek

We grew leek (Allium porrum) in soils of two shooting ranges heavily contaminated with heavy metals in the towns of Zuchwil and Oberuzwil in Switzerland as a bioassay to test theactivity of arbuscular mycorrhizal (AM) fungi in these soils.Soil samples were taken from (1) front of the shooting house(HOUSE), (2) the area between house and target (FIELD) and (3) the berm (BACKSTOP). Samples of Ribwort plantain (Plantagolanceolata) growing naturally within the shooting ranges werealso collected and the colonization of its roots by mycorrhizalfungi was measured. The number of AM spores in the soils wassignificantly reduced concomitant with the increase in thedegree of soil contamination with metals. In Zuchwil,mycorrhizal fungi equally colonized roots of Ribwort plantainsampled from BACKSTOP and HOUSE. In Oberuzwil, however, plantsfrom BACKSTOP had lower colonization when compared with thosesampled from HOUSE. Colonization of leek was strongly reducedin the BACKSTOP soil of Zuchwil and slightly reduced in theBACKSTOP soil of Oberuzwil when compared with plants grown inrespective HOUSE soil. Concentrations of Cd, Cr, Cu, Ni, Pb andZn in the leaves of leek grown in the BACKSTOP soil was withinthe range considered toxic for human consumption. This pointsto the high degree of bio-availability of these metal in thesesoils. Significant decrease in the number of mycorrhizal sporesin the BACKSTOP soils in Zuchwil and the low colonization ofleek roots grown in these soils point to possible changes inthe species diversity of mycorrhizal fungi in these soil

Transcription-translation coupling: direct interactions of RNA polymerase with ribosomes and ribosomal subunits.

In prokaryotes, RNA polymerase and ribosomes can bind concurrently to the same RNA transcript, leading to the functional coupling of transcription and translation. The interactions between RNA polymerase and ribosomes are crucial for the coordination of transcription with translation. Here, we report that RNA polymerase directly binds ribosomes and isolated large and small ribosomal subunits. RNA polymerase and ribosomes form a one-to-one complex with a micromolar dissociation constant. The formation of the complex is modulated by the conformational and functional states of RNA polymerase and the ribosome. The binding interface on the large ribosomal subunit is buried by the small subunit during protein synthesis, whereas that on the small subunit remains solvent-accessible. The RNA polymerase binding site on the ribosome includes that of the isolated small ribosomal subunit. This direct interaction between RNA polymerase and ribosomes may contribute to the coupling of transcription to translation

Drug Delivery Micropump with Built-In Monitoring

AbstractWe report on the fabrication of the first MEMS micropump including an integrated pressure sensor. The signal of this sensor allows direct insight into the pump's operating dynamics and enables real-time self-monitoring. We demonstrate the changes in the sensor signal under different pumping conditions, including the presence of air in the pumping chamber and a downstream occlusions. Deviations from normal operating conditions create clear and characteristic deviations from the normal signal. These deviations will be exploited to detect extraordinary or faulty pumping conditions during use

Anterior implant restorations with a convex emergence profile increase the frequency of recession: 12-month results of a randomized controlled clinical trial

AIM To test whether the emergence profile (CONVEX or CONCAVE) of implant-supported crowns influences the mucosal margin stability up to 12 months after insertion of the final restoration. MATERIALS AND METHODS Forty-seven patients with a single implant in the anterior region were randomly allocated to one of three groups: (1) CONVEX (n = 15), implant provisional and an implant-supported crown both with a convex profile; (2) CONCAVE (n = 16), implant provisional and an implant-supported crown both with a concave profile; (3) CONTROL (n = 16), no provisional (healing abutment only) and an implant-supported crown. All patients were recalled at baseline, 6, and 12 months. The stability of mucosal margin along with clinical, aesthetic, and profilometric outcomes as well as time and costs were evaluated. To predict the presence of recession, multivariable logistic regressions were performed and linear models using generalized estimation equations were conducted for the different outcomes. RESULTS Forty-four patients were available at 12 months post-loading. The frequency of mucosal recession amounted to 64.3% in group CONVEX, 14.3% in group CONCAVE, and 31.4% in group CONTROL. Regression models revealed that a CONVEX profile was significantly associated with the presence of recessions (odds ratio: 12.6, 95% confidence interval: 1.82-88.48, p = .01) compared with the CONCAVE profile. Pink aesthetic scores amounted to 5.9 in group CONVEX, 6.2 in group CONCAVE, and 5.4 in group CONTROL, with no significant differences between the groups (p = .735). Groups CONVEX and CONCAVE increased the appointments and costs compared with the CONTROL group. CONCLUSIONS The use of implant-supported provisionals with a CONCAVE emergence profile results in a greater stability of the mucosal margin compared with a CONVEX profile up to 12 months of loading. This is accompanied, however, by increased time and costs compared with the absence of a provisional and may not necessarily enhance the aesthetic outcomes. TRIAL REGISTRATION German Clinical Trials Register; DRKS00009420

A monoclinic polymorph of N-eth­oxy­carbonyl-N′-(3-phenyl-1H-1,2,4-triazol-5-yl)thio­urea

The title compound, C12H13N5O2S {systematic name: ethyl N-[N-(3-phenyl-1H-1,2,4-triazol-5-yl)carbamothio­yl]carbamate}, is a monoclinic polymorph (space group P21/c) which crystallizes with three similar independent mol­ecules in the asymmetric unit. The triazole ring makes dihedral angles of 6.6 (2), 8.4 (2) and 10.6 (2)° with the phenyl ring in the three independent molecules. The structure was previously reported [Dolzhenko et al. (2010a ▶). Acta Cryst., E46, o425] as a triclinic polymorph crystallizing in space group P . Mol­ecules in both polymorphs possess two S(6) rings generated by intra­molecular N—H⋯S and N—H⋯O hydrogen bonds, resulting in similar mol­ecular geometries. However, the two polymorphs differ in the crystal packing. In contrast to the dimers of the triclinic polymorph, mol­ecules of the monoclinic polymorph are connected by inter­molecular N—H⋯S and N—H⋯N hydrogen bonds, forming pseudosymmetric trimers arranged in sheets parallel to (302)

Evidence for structural deformation of the DNA helix by a psoralen diadduct but not by a monoadduct

We have investigated the structural change in a double-stranded DNA helix caused by covalent addition of a psoralen. A synthetic double-stranded DNA was constructed to contain either a psoralen furan-side monoadduct or an interstrand diadduct at a specific site. When the unmodified and psoralen modified DNAs were examined by electron microscopy in the presence of distamycin, which stiffens the DNA helix, the DNA containing the psoralen interstrand diadduct appeared bent (or kinked), whereas the furan-side monoadducted DNA appeared similar to the unmodified DNA

Structural basis for +1 ribosomal frameshifting during EF-G-catalyzed translocation

Frameshifting of mRNA during translation provides a strategy to expand the coding repertoire of cells and viruses. How and where in the elongation cycle +1-frameshifting occurs remains poorly understood. We describe seven ~3.5-A-resolution cryo-EM structures of 70S ribosome complexes, allowing visualization of elongation and translocation by the GTPase elongation factor G (EF-G). Four structures with a + 1-frameshifting-prone mRNA reveal that frameshifting takes place during translocation of tRNA and mRNA. Prior to EF-G binding, the pre-translocation complex features an in-frame tRNA-mRNA pairing in the A site. In the partially translocated structure with EF-G*GDPCP, the tRNA shifts to the +1-frame near the P site, rendering the freed mRNA base to bulge between the P and E sites and to stack on the 16S rRNA nucleotide G926. The ribosome remains frameshifted in the nearly post-translocation state. Our findings demonstrate that the ribosome and EF-G cooperate to induce +1 frameshifting during tRNA-mRNA translocation

Analysis of sequential steps of nucleotide excision repair in Escherichia coli using synthetic substrates containing single psoralen adducts

Escherichia coli ABC excinuclease initiates the removal of dodecanucleotides from damaged DNA in an ATP-dependent reaction. Using a synthetic DNA fragment containing a psoralen adduct at a defined position we have investigated the interaction of the components of the enzyme with substrate by DNase I footprinting. We find that the UvrA subunit binds to DNA specifically in the absence of cofactors and that the binding affinity is stimulated about 4-fold by ATP and only marginally inhibited by ADP. The UvrA.DNA complexes formed in the absence of co-factors or in the presence of either ATP or ADP are remarkably similar. In contrast, adenosine 5'-O-(thiotriphosphate) increases nonspecific binding and completely abolishes the UvrA footprint. The UvrB subunit can associate with the UvrA subunit on DNA in the absence of ATP, but this ternary UvrA.UvrB.DNA complex is qualitatively different from that formed in the presence of ATP. The UvrC subunit elicits no additional change in the UvrA-UvrB footprint. Helicase II (UvrD protein) does not alter the UvrA-UvrB footprint but does appear to interact at the 5'-incision site of the postincision complex. DNA polymerase I fills in the excision gap in the presence or absence of helicase II and apparently releases the ABC excinuclease from the repaired DNA. Nearly 90% of the repair patches are 12 nucleotides long, and this length is not affected by helicase II. We see no evidence by DNase I footprinting for the formation of a multiprotein complex encompassing the UvrA, -B, -C, and -D proteins and DNA polymerase I