Whole Genome PCR Scanning Reveals the Syntenic Genome Structure of Toxigenic Vibrio cholerae Strains in the O1/O139 Population

Vibrio cholerae is commonly found in estuarine water systems. Toxigenic O1 and O139 V. cholerae strains have caused cholera epidemics and pandemics, whereas the nontoxigenic strains within these serogroups only occasionally lead to disease. To understand the differences in the genome and clonality between the toxigenic and nontoxigenic strains of V. cholerae serogroups O1 and O139, we employed a whole genome PCR scanning (WGPScanning) method, an rrn operon-mediated fragment rearrangement analysis and comparative genomic hybridization (CGH) to analyze the genome structure of different strains. WGPScanning in conjunction with CGH revealed that the genomic contents of the toxigenic strains were conservative, except for a few indels located mainly in mobile elements. Minor nucleotide variation in orthologous genes appeared to be the major difference between the toxigenic strains. rrn operon-mediated rearrangements were infrequent in El Tor toxigenic strains tested using I-CeuI digested pulsed-field gel electrophoresis (PFGE) analysis and PCR analysis based on flanking sequence of rrn operons. Using these methods, we found that the genomic structures of toxigenic El Tor and O139 strains were syntenic. The nontoxigenic strains exhibited more extensive sequence variations, but toxin coregulated pilus positive (TCP+) strains had a similar structure. TCP+ nontoxigenic strains could be subdivided into multiple lineages according to the TCP type, suggesting the existence of complex intermediates in the evolution of toxigenic strains. The data indicate that toxigenic O1 El Tor and O139 strains were derived from a single lineage of intermediates from complex clones in the environment. The nontoxigenic strains with non-El Tor type TCP may yet evolve into new epidemic clones after attaining toxigenic attributes

Dynamic phenotypic heterogeneity and the evolution of multiple RNA subtypes in Hepatocellular Carcinoma: the PLANET study

Intra-tumor heterogeneity (ITH) is a key challenge in cancer treatment, but previous studies have focused mainly on the genomic alterations without exploring phenotypic (transcriptomic and immune) heterogeneity. Using one of the largest prospective surgical cohorts for Hepatocellular Carcinoma (HCC) with multi-region sampling, we sequenced whole genomes and paired transcriptomes from 67 HCC patients (331 samples). We found that while genomic ITH was rather constant across TNM stages, phenotypic ITH had a very different trajectory and quickly diversified in stage II patients. Most strikingly, 30% patients were found to contain more than one transcriptomic subtype within a single tumor. Such phenotypic ITH was found to be much more informative in predicting patient survival than genomic ITH and explains the poor efficacy of single-target systemic therapies in HCC. Taken together, we not only revealed an unprecedentedly dynamic landscape of phenotypic heterogeneity in HCC, but also highlighted the importance of studying phenotypic evolution across cancer types

Ruthenium porphyrin encapsulated in modified mesoporous molecular sieve MCM-41 for alkene oxidation

Ruthenium(II) meso-tetrakis(4-chlorophenyl)porphyrin encapsulated in MCM-41 modified with 3-aminopropyltriethoxysilane is a stable catalyst for alkene oxidation by tertbutyl hydroperoxide with high product turnovers.link_to_subscribed_fulltex

MCM-41-supported cis-diaquabis(6,6'-dichloro-2,2'-bipyridine) ruthenium(II) complex. Immobilisation, characterisation and catalytic activities

cis-[Ru(II)(6,6'-Cl2bpy)2(OH2)2](CF3SO3)2 (6,6'-Cl2bpy = 6,6'- dichloro-2,2'-bipyridine) was immobilised into the mesoporous molecular sieve MCM-41 by a simple and direct method and the highest loading of cis- [Ru(II)(6,6'-Cl2bpy)2(OH2)2](CF3SO3)2 achieved was 8.4 wt%. The supported ruthenium complex, designated as Ru/MCM-41, has been characterised by elemental analyses, N2 adsorption isotherm, X-ray diffraction (XRD), thermogravimetric and differential thermal analyses (TG-DTA), UV-visible and FT-Raman spectroscopies. XRD spectra showed that the immobilised cis- [Ru(II)(6,6'-Cl2bpy)2(OH2)2](CF3SO3)2 was not in a crystalline form and the MCM-41 structure was retained. Preliminary studies revealed that the Ru/MCM-41 materials catalysed the oxidation of alkanes by tert- butylhydroperoxide (TBHP) with high turnover. High catalytic activity has been obtained with low ruthenium loading catalysts.link_to_subscribed_fulltex

Comparison of [ 125I]iodomelatonin binding sites in infant cerebellum of sudden infant death syndrome and non-sudden infant death syndrome

[ 125I]Iodomelatonin binding sites in human infant cerebellum were studied by radioligand receptor binding assay and in vitro quantitative autoradiography. The binding sites characterized in membrane preparations revealed saturable, reversible and highly specific binding sites with a K(d) value of 21.2 ± 8.33 pM and a B(max) value of 2.02 ± 0.52 fmol/mg protein. 10 μM of CGPγS significantly reduced the binding capacity, suggesting the possible G-protein coupling of the binding sites. Autoradiographic study showed that the labelling was mainly located in the cerebellar cortex. On comparison of the binding parameters from cerebellum of sudden infant death syndrome (SIDS) and non-SIDS infants, no significant change in binding capacity and binding affinity was detected. These findings suggest that the binding sites in cerebellum may not be related to the etiology of SIDS.link_to_subscribed_fulltex

Synthesis and structural characterisation of two- and three-dimensional fluorinated indium phosphates

Hydrothermal synthesis of two new fluorinated indium phosphates [InPO4F(Hen)] and [In5P4F3O16(en)(3)(OH2)(2)] is carried out in the system In2O3-P2O5-en-HF-H2O (en = ethylenediamine); these have two- and three-dimensional inorganic frameworks respectively, with the latter having ten-membered ring channels spanned by coordinated en; the fluorides bridge exclusively between indium ions and may be linear or bent

AN IR STUDY ON ADSORPTION OF CO AND NO ON COPPER ION-EXCHANGED ZEOLITE-BETA

The adsorption of CO and NO on copper ion-exchanged zeolite Beta was investigated using IR method. It was found that the thermal vacuum pretreatment procedure could result in the reduction of CU2+ ions in zeolite Beta. The adsorption of CO on Cu+ sites in zeolite Beta closely follows Langmuir isotherm. Another Cu+ species may form during the reaction between water and CO. The catalytic decomposition of NO on the zeolite was observed at room temperature, indicating that the decomposition reaction may occur between two coordinated NO ligands of the same dinitrosylic complex. Furthermore, the appearance of two series of NO adsorption bands reveals that copper ions existing at different cation sites may have different effect on the adsorption and decomposition of NO molecules

Irradiation hardening induced by blistering in tungsten due to low-energy high flux hydrogen plasma exposure

\u3cp\u3eIn this work, the microstructure evolution in the near-surface of tungsten under hydrogen (H)plasma exposure conditions was observed by means of scanning electron microscopy (SEM), plasma focused ion beam (FIB)and transmission electron microscopy (TEM)techniques. Blisters, with existing dislocations distributed around obviously, were observed beneath the tungsten surface when the exposure temperature was 573 K, which was rarely reported in previous studies. However, H bombardment at 1273 K did not lead to the formation of blister-like microstructures. Correspondingly, irradiation hardening occurred after low temperature exposure, but not after high temperature exposure, according to the Berkovich nano-indentation experiments. In order to characterize the indentation size effect and irradiation hardening behavior of plasma-exposed materials, a mechanistic model was proposed for the hardness-depth relationship. A good agreement between the experimental indentation data and theoretical results revealed that plasma-induced dislocations play a dominant role in determining the increase of hardness for H plasma-exposed tungsten.\u3c/p\u3

Dense A-type zeolite membrane synthesized by seeding

The synthesis of A-type zeolite membranes on porous alpha -Al2O3 supports via the method of seeding plus secondary hydrothermal crystallization has been studied. The seed layers, which were prepared from colloidal A-type zeolite synthesized from the reaction mixture of n[(TMA)(2)O] : n(SiO2) n (Al2O3) : n(Na2O) : n(H2O) = 13.4 : 11.25 : 1.8 : 0.3 : 700, were treated by steam of ammonia to inhibit the formation of cracks when dried. Compact zeolite membranes constituted with multiple-twined zeolite crystals were accessed by hydrothermal growth of seed layers in the reaction sol of n (Na2O) n(Al2O3) : n(SiO2) = n(H2O) = 3 : 1 : 1 : 800. In highly alkaline hydrothermal solutions, seed layers tended to dissolve and loose zeolite membranes with many defects were obtained. The gas permeanbility on A-type zeolite membrane dried at 393 K, in which water molecular still inhabited the zeolitic channels, was quite low, suggesting that the membrane was close to free of defects. Defects were formed mainly due to different thermal expansion coefficients between alpha -Al2O3 support and zeolite membrane when the calcinations at 823 K was carried out to free the channel of membrane zeolites