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The closure of the Mongol-Okhotsk Ocean in Jurassic – Cretaceous times led to the final amalgamation of the interior of Eastern Asia, thus placing Mongolia in an intraplate tectonic setting. Small and widespread volcanic fields of Mesozoic and Cenozoic age are known through Eastern Asia, attributed to both post-collisional and intraplate mechanisms. In Mongolia, intraplate volcanic fields are scattered across the central and eastern parts of the country. Although several models have been proposed to explain the origin of this late Mesozoic – Cenozoic intraplate magmatism in Mongolia, there is still on-going debate about the process(es) that lead to it. Moreover, there are no temporal reconstructions on the extent of post-collisional magmatism in the area preceding intraplate magmatic activity, nor any hypotheses on the timing of the onset of the latter. In this study, we differentiate between post-collisional and intraplate magmatism in Mongolia using a set of geochemical, isotopic, palaeomagnetic and zircon data, and define the onset of intraplate magmatic activity at 107 Ma. Through evaluation of nearly 700 published radiometric data from the various volcanic fields across Mongolia along with newly-obtained age constraints, we reveal a complex temporal and spatial evolution of the magmatism that runs parallel in different volcanic fields through time, and we identify the extent of hiatuses in the magmatic activity. Based on the assessed data we discuss the source of bias in our understanding of the magmatic history of Mongolia and evaluate the various proposed models for the origin of the Mongolian magmatism. Finally, we suggest that asthenospheric upwellings were induced through a delamination event beneath Mongolia in the late Mesozoic. This initiated the intraplate magmatism, the temporal evolution of which is prolonged due to enhanced mantle flow related to northward progression of Tethys and the Indian plate.

Rapid cooling of planetesimal cores has been inferred for several iron meteorite parent bodies on the basis of metallographic cooling rates, and linked to the loss of their insulating mantles during impacts. However, the timing of these disruptive events is poorly constrained. Here, we used the short-lived 107Pd–107Ag decay system to date rapid core cooling by determining Pd–Ag ages for iron meteorites. We show that closure times for the iron meteorites equate to cooling in the time frame ~7.8–11.7 Myr after calcium–aluminium-rich inclusion formation, and that they indicate that an energetic inner Solar System persisted at this time. This probably results from the dissipation of gas in the protoplanetary disk, after which the damping effect of gas drag ceases. An early giant planet instability between 5 and 14 Myr after calcium–aluminium-rich inclusion formation could have reinforced this effect. This correlates well with the timing of impacts recorded by the Pd–Ag system for iron meteorites., Nature Astronomy, 6 (7), ISSN:2397-3366

Sir, In the UK prior to 2008, resistance to carbapenems was generally confined to non-fermenters. In recent years carbapenemases have been increasingly seen in Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae. Following an alert from the Antibiotic Resistance & Monitoring Reference Laboratory (ARMRL) in January 2009 regarding the increase in carbapenemaseproducing Enterobacteriaceae in the UK, draft guidance issued from Health Protection Scotland recommended the investigation of Enterobacteriaceae isolates with an MIC of .0.5 mg/L by the modified Hodge test and the use of combination discs. Similar recommendations are made in other European guidelines. We use Vitek 2 (bioMerieux, Marcy l’Etoile, France) for susceptibility testing and, for Enterobacteriaceae with a meropenem MIC .0.5 mg/L, we then perform a meropenem Etest (bioMerieux), and in some cases a modified Hodge test. In order to determine the optimal procedure for investigating such isolates in our laboratory we analysed data from a retrospective search of the laboratory database from 1 September 2009 to 31 August 2010. A total of 48 isolates were found to have had a meropenem MIC .0.5 mg/L by Vitek 2 and also had an Etest. Results were interpreted according to CLSI methodology. The organisms identified were Escherichia coli (n1⁄423), Enterobacter spp. (n1⁄412), Klebsiella spp. (n1⁄46), Proteus spp. (n1⁄42), Serratia spp. (n1⁄42), Citrobacter spp. (n1⁄41), Providencia stuartii (n1⁄41) and Hafnia alvei (n1⁄41). The specimen types these organisms were isolated from were urine (n1⁄439), general swabs and fluids (n1⁄44), respiratory samples (n1⁄44) and CSF (n1⁄41). Vitek 2 meropenem MICs ranged from 1 to ≥16 mg/L, including 23 isolates (48%) with MICs in the susceptible range (≤2 mg/L). Forty-one isolates were confirmed as meropenem susceptible (≤2 mg/L) by Etest and seven isolates had meropenem MICs .2 mg/L by Etest. In 44 cases the Etest MIC was lower than the Vitek 2 MIC; of these, 21 isolates were susceptible by both methods, 18 were resistant when measured by Vitek 2 and susceptible by Etest and 5 were resistant by both methods. One isolate had the same MIC by both Vitek 2 and Etest. In three cases the Etest MIC was greater than the Vitek 2 MIC; of these, one isolate was susceptible by both methods and two isolates were resistant by both methods. Modified Hodge tests were performed on 12 isolates; 11 were negative and 1 was positive. The positive isolate was an Enterobacter cloacae with a Vitek 2 MIC of 8 mg/L and an Etest MIC of 32 mg/L. The meropenem Etest MIC range for isolates that had a

The bldC locus, required for formation of aerial hyphae in Streptomyces coelicolor , was localized by map-based cloning to the overlap between cosmids D17 and D25 of a minimal ordered library. Subcloning and sequencing showed that bldC encodes a member of a previously unrecognized family of small (58- to 78-residue) DNA-binding proteins, related to the DNA-binding domains of the MerR family of transcriptional activators. BldC family members are found in a wide range of gram-positive and gram-negative bacteria. Constructed ΔbldC mutants were defective in differentiation and antibiotic production. They failed to form an aerial mycelium on minimal medium and showed severe delays in aerial mycelium formation on rich medium. In addition, they failed to produce the polyketide antibiotic actinorhodin, and bldC was shown to be required for normal and sustained transcription of the pathway-specific activator gene actII-orf4 . Although ΔbldC mutants produced the tripyrrole antibiotic undecylprodigiosin, transcripts of the pathway-specific activator gene ( redD ) were reduced to almost undetectable levels after 48 h in the bldC mutant, in contrast to the bldC + parent strain in which redD transcription continued during aerial mycelium formation and sporulation. This suggests that bldC may be required for maintenance of redD transcription during differentiation. bldC is expressed from a single promoter. S1 nuclease protection assays and immunoblotting showed that bldC is constitutively expressed and that transcription of bldC does not depend on any of the other known bld genes. The bldC18 mutation that originally defined the locus causes a Y49C substitution that results in instability of the protein.