Search

Abstract Transcription, a critical process in molecular biology, has found many applications in RNA synthesis, including mRNA vaccines and RNA therapeutics. However, current RNA characterization technologies suffer from amplification and enzymatic biases that lead to loss of native information. Here, we introduce a strategy to quantitatively study both transcription and RNA polymerase behaviour by sizing RNA with RNA nanotechnology and nanopores. To begin, we utilize T7 RNA polymerase to transcribe linear DNA lacking termination sequences. Surprisingly, we discover alternative transcription termination in the origin of replication sequence. Next, we employ circular DNA without transcription terminators to perform rolling circle transcription. This allows us to gain valuable insights into the processivity and transcription behaviour of RNA polymerase at the single-molecule level. Our work demonstrates how RNA nanotechnology and nanopores may be used in tandem for the direct and quantitative analysis of RNA transcripts. This methodology provides a promising pathway for accurate RNA structural mapping by enabling the study of full-length RNA transcripts at the single-molecule level.

Plasma volume (PV) undergoes constant and dynamic changes, leading to a large intra-day variability in healthy individuals. Hydration is known to induce PV changes; however, the response to the intake of osmotically different fluids is still not fully understood. In a randomized controlled crossover trial, 18 healthy individuals (10 females) orally received an individual amount of an isotonic sodium-chloride (ISO), Ringer (RIN), or glucose (GLU) solution. Hemoglobin mass (Hbmass) was determined with the optimized carbon monoxide re-breathing method. Fluid-induced changes in PV were subsequently calculated based on capillary hemoglobin concentration ([Hb]) and hematocrit (Hct) before and then every 10 minutes until 120 min (t0–120) after the fluid intake and compared to a control trial arm (CON), where no fluid was administered. Within GLU and CON trial arms, no statistically significant differences from baseline until t120 were found (p > 0.05). In the ISO trial arm, PV was significantly increased at t70 (+138 mL, p = 0.01), t80 (+191 mL, p < 0.01), and t110 (+182 mL, p = 0.01) when compared to t0. Moreover, PV in the ISO trial arm was significantly higher at t70 (p = 0.02), t110 (p = 0.04), and t120 (p = 0.01) when compared to the same time points in the CON trial arm. Within the RIN trial arm, PV was significantly higher between t70 and t90 (+183 mL, p = 0.01) and between t110 (+194 mL, p = 0.03) and t120 (+186 mL, p < 0.01) when compared to t0. These results demonstrated that fluids with a higher content of osmotically active particles lead to acute hemodilution, which is associated with a decrease in [Hb] and Hct. These findings underpin the importance of the hydration state on PV and especially on PV constituent levels in healthy individuals.

The title compound, [IrZnI2(C10H15)(C3H9P)2]·0.5C6H6 or [Cp*(PMe3)2Ir]-[ZnI2] (Cp* = cyclo-C5Me5) was obtained and characterized as its benzene solvate [Cp*(PMe3)2Ir]-[ZnI2]·0.5C6H6. The bimetallic complex in this structure contains the Lewis-acidic fragment ZnI2 bonded to the Lewis-basic fragment Cp*(PMe3)2Ir, with an Ir—Zn bond distance of 2.452 (1) Å. The compound was obtained by reacting [Cp*(PMe3)IrI2] with 2-Ad2Zn (2-Ad = 2-adamantyl), resulting in the reduction of the IrIII complex and formation of the IrI–ZnII adduct. The crystal studied was a twin by non-merohedry with a refined BASF parameter of 0.223 (1).

The synthesis and structural characterization of the molecular compound (μ3-benzene-1,2-dithiolato)hexacarbonylbis(μ3-1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolato)tricobaltmolybdenum, [Co3Mo(C4F6S2)2(C6H4S2)(CO)6] or Mo(tfd)2(bdt)(Co(CO)2)3 (tfd is 1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolate and bdt is benzene-1,2-dithiolate), are reported. The structure of the molecule contains the molybdenum tris(dithiolene) complex Mo(tfd)2(bdt) coordinated as a multidentate ligand to three cobalt dicarbonyl units. Each of the three cobalt centers is relatively close to molybdenum, with Co...Mo distances of 2.7224 (7), 2.8058 (7), and 2.6320 (6) Å. Additionally, each of the cobalt centers is bound via main-group donor atoms, but each one in a different way: the first cobalt atom is coordinated by two sulfur atoms from different dithiolenes (bdt and tfd). The second cobalt atom is coordinated by one sulfur from one tfd and two olefinic carbons from another tfd. The third cobalt is coordinated by one sulfur from bdt and two sulfurs from tfd. This is, to the best of our knowledge, the first structurally characterized example of a molybdenum (tris)dithiolene complex that coordinates to cobalt. The F atoms of two of the –CF3 groups were refined as disordered over two sets of sites with ratios of refined occupancies of 0.703 (7):0.297 (7) and 0.72 (2):0.28 (2).

The complex cation in the title compound, (carbonyl-1κC)(1η5-pentamethylcyclopentadienyl)(μ-2,3,9,10-tetramethyl-1,4,8,11-tetrathiaundeca-2,9-diene-1,11-diido-1κ2S,S′′′:2κ4S,S′,S′′,S′′′)ironnickel(Fe—Ni) hexafluorophosphate, [FeNi(C10H15)(C11H18S4)(CO)]PF6 or [Ni(L′)FeCp*(CO)]PF6, is composed of the nickel complex fragment [Ni(L′)] coordinated as a metalloligand (using S1 and S4) to the [FeCp*(CO)]+ fragment, where (L′)2− is [S—C(Me)=C(Me)—S—(CH2)3—S—C(Me)=C(Me)—S]2− and where Cp*− is cyclo-C5(Me)5− (pentamethylcyclopentadienyl). The ratio of hexafluorophosphate anion per complex cation is 1:1. The structure at 150 K has orthorhombic (Pbcn) symmetry. The atoms of the complex cation are located on general positions (multiplicity = 8), whereas there are two independent hexafluorophosphate anions, each located on a twofold axis (Wyckoff position 4c; multiplicity = 4). The structure of the new dimetallic cation [Ni(L′)FeCp*(CO)]+ can be described as containing a three-legged piano-stool environment for iron [Cp*Fe(CO)`S2'] and an approximately square-planar `S4' environment for Ni. The NiS2Fe diamond-shaped substructure is notably folded at the S—S hinge: the angle between the NiS2 plane and the FeS2 plane normals is 64.85 (6)°. Largely because of this fold, the nickel–iron distance is relatively short, at 2.9195 (8) Å. The structural data for the complex cation, which contains a new unsaturated `S4' ligand (two C=C double bonds), provide an interesting comparison with the known NiFe hydrogenase models containing a saturated `S4'-ligand analogue having the same number of carbon atoms in the ligand backbone, namely with the structures of [Ni(L)FeCp(CO)]+ (as the PF6− salt, CH2Cl2 solvate) and [Ni(L)FeCp*(CO)]+ (as the PF6− salt), where (L)2− is [S—CH2—CH2—S—(CH2)3—S—CH2—CH2—S]2− and Cp− is cyclopentadienyl. The saturated analogues [Ni(L)FeCp(CO)]+ and [Ni(L)FeCp*(CO)]+ have similar Ni—Fe distances: 3.1727 (6), 3.1529 (7) Å (two independent molecules in the unit cell) and 3.111 (5) Å, respectively, for the two complexes, whereas [Ni(L′)FeCp*(CO)]+ described here stands out with a much shorter Ni—Fe distance [2.9196 (8) Å]. Also, [Ni(L)FeCp(CO)]+ and [Ni(L)FeCp*(CO)]+ show interplanar fold angles that are similar between the two: 39.56 (5), 41.99 (5) (independent molecules in the unit cell) and 47.22 (9) °, respectively, whereas [Ni(L′)FeCp*(CO)]+ possesses a much more pronounced fold [64.85 (6)°]. Given that larger fold angles and shorter Ni—Fe distances are considered to be structurally closer to the enzyme, unsaturation in an `S4'-ligand of the type (S—C2—S—C3—S—C2—S)2− seems to increase structural resemblance to the enzyme for structural models of the type [Ni(`S4')FeCpR(CO)]+ (CpR = Cp or Cp*).

The title compound, hexakis[μ3-1,2-bis(trifluoromethyl)ethene-1,2-dithiolato]-octahedro-hexapalladium(II), [Pd(C4F6S2)]6, crystallizes as its benzene solvate, [Pd(tfd)]6·2.5C6H6, where tfd is the dithiolene S2C2(CF3)2. The molecular structure of [Pd(tfd)]6 is of the hexametallic cube type seen previously in three examples of hexameric homoleptic palladium monodithiolene structures. All structures have in common: (a) the cluster closely approximates a cube containing six PdII atoms, one at the centre of each cube face; (b) 12 S atoms occupy the mid-points of all 12 cube edges, providing for each PdII atom an approximately square-planar S4 environment; (c) each S atom is part of a dithiolene molecule, where the size of the dithiolene ligand necessitates that only sulfur atoms on adjacent cube edges can be part of the same dithiolene. This general cube-type framework has so far given rise to two isomeric types: an S6-symmetric isomer and a C2-chiral type (two isomers that are enantiomers of each other). The structure of [Pd(tfd)]6 is of the C2-type. Out of the 12 CF3 groups, three are rotationally disordered over two positions. Further, we answer the question of whether additional, previously undiscovered, isomers could follow from the cube rules (a) through (c) above. An exhaustive analysis shows that no additional isomers are possible and that the list of isomers (one S6 isomer, two C2 enantiomers) is complete. Each isomer type could give rise to an unlimited number of compounds if the specific dithiolene used is varied.

Ulrich Feifel1, Gudrun Wallenstein1, Karl-Ludwig Rominger1, Dirk Trommeshauser2, Juliane Platz21Boehringer Ingelheim Pharma GmbH & Co. KG, Binger Straße 173, 55216 Ingelheim, Germany; 2Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorf Straße 65, 88397 Biberach, GermanyAbstract: Data are presented from two randomized, double-blind, placebo-controlled studies in which the tolerability of tiotropium Respimat® Soft Mist™ Inhaler (SMI), a new-generation, propellant-free device for use in COPD, and the ocular safety of tiotropium were examined. In Study 1, 36 healthy males received tiotropium 8, 16, or 32 µg (n = 9/dose) or placebo (n = 3/dose level), administered once daily via Respimat® SMI for 14 days. Safety and pharmacokinetics were evaluated. In Study 2, 48 healthy males received tiotropium 0.02, 0.04, 0.08, 0.16, 0.28, or 0.40 µg (n = 6/dose) or placebo (n = 2/dose level), applied as two drops to one eye (the highest dose was a significant multiple of a percentage of the proposed Respimat® SMI clinical dose that could be inadvertently deposited in the eye). Ocular parameters were measured over 24 hours. Tiotropium Respimat® SMI at doses up to 32 µg was well tolerated in Study 1; typical dose-dependent anticholinergic adverse events of mild-to-moderate intensity were observed. In Study 2, ocular tiotropium administration did not affect pupil diameter, pupillary reflex, intraocular pressure, or accommodation. Tiotropium Respimat® SMI was well tolerated. Inadvertent ocular exposure to tiotropium up to 0.40 µg is unlikely to result in ocular adverse effects.Keywords: Respimat® Soft Mist™ Inhaler, tiotropium, anticholinergic, chronic obstructive pulmonary disease

Nonlinear optical microscopy was used to image the localization of astaxanthin accumulation in the green alga, Haematococcus pluvialis. Polarization-in, polarization-out (PIPO) second harmonic generation (SHG) and third harmonic generation (THG) microscopy was applied to study the crystalline organization of astaxanthin molecules in light-stressed H. pluvialis in vivo. Since astaxanthin readily forms H- and J-aggregates in aqueous solutions, PIPO THG studies of astaxanthin aggregates contained in red aplanospores were compared to PIPO THG of in vitro self-assembled H- and J-aggregates of astaxanthin. The PIPO THG data clearly showed an isotropic organization of astaxanthin in red aplanospores of H. pluvialis. This is in contrast to the highly anisotropic organization of astaxanthin in synthetic H- and J-aggregates, which showed to be uniaxial. Since carotenoids in vitro preferentially form H- and J-aggregates, but in vivo form a randomly organized structure, this implies that astaxanthin undergoes a different way of packing in biological organisms, which is either due to the unique physical environment of the alga or is controlled enzymatically.

In the wake of the redefinition of the kilogram, the last unit of the International System of Units (SI) that is still based on a man-made artefact, discussions were launched on the necessity of redefining other units, amongst other the unit mole. Since 1971 the mole is defined as the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. The symbol of the unit is 'mol'. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles. The definition is based on the pre-existing choice to set the relative atomic mass of carbon 12 equal to 12 exactly. In the proposed new definition the mole is the amount of substance containing exactly 6.022 141 79 × 1023 atoms or molecules, ions, electrons, other particles, or specified groups of such particles, i.e. the Avogardo constant would have a fixed value without an uncertainty. This contribution critically examines the submitted arguments to justify the proposed redefinition of the unit mole by 2011 for their persuasive power to change a scientific and cultural good such as a unit of measurement. As shown, there are no convincing scientific arguments for a redefinition of the mole that stand a closer examination. The current definition is well understood, established in science and technology for almost 50 years and is still up to date.

In the title compound, (C24H20As)[Pt(C4F6S2)2], the cation lies on a twofold rotation axis while the anion has crystallographic inversion symmetry. The PtII ion is in a slightly distorted square-planar coordination environment. The F atoms of both unique –CF3 groups are disordered over two sets of sites, the ratios of refined occupancies being 0.677 (15):0.323 (15) and 0.640 (16):0.360 (16). The crystal structure is the first to date of a monoanionic [Pt(tfd)2]− species [tfd is 1,2-bis(trifluoromethyl)ethene-1,2-dithiolate] with a non-redox-active cation.