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Abstract The continental lithosphere is not forever; some cratons have lost their original roots during the course of their evolution. Yet, it is not clear whether gravitational instability of dense lower crust is the primary driver of decratonization. This is addressed here with emphasis being placed on the North China Craton (NCC), because it represents one of the best examples of craton-root disruption in the world, and a place where models can be tested. If lower-crustal delamination was the trigger for decratonization, we would expect a clear contrast in crustal structure and composition between disturbed (rootless) and intact cratons. However, the eastern (disturbed) and western (intact) parts of the NCC show virtually identical physical structure and composition (a thin mafic lower crust and a predominantly intermediate composition overall) although the crust in the disturbed part is thinner than in the intact craton. This suggests that delamination of the lower crust was not a viable mechanism of craton-root disruption in the NCC case. Indeed, the crust beneath the NCC largely resembles those of stable Archean cratons worldwide. Therefore the delamination, if it occurred, may have taken place much earlier (Archean) than previously thought, rather than in the Mesozoic. Delamination may have been a common phenomenon in the early evolution of cratons, probably due to relatively higher mantle temperatures in the Archean Eon. Highlights • A combined geophysical and geochemical study on the crust of the North China Craton. • Both crust beneath disrupted and intact parts of the craton are low-Vp and andesitic. • Lower-crustal delamination is not a cause of the decratonicization. • Delamination could be a common process in all Archean cratons. [ABSTRACT FROM AUTHOR]

Highly magnesian ultrapotassic rocks that erupted ca. 30-40 Ma on either side of the northern Ailao Shan-Red River fault (western Yunnan) have initial [sup.87]Sr/[sup.86]Sr values of 0.7064-0.7094 and [[Epsilon].sub.Nd] values of -3.8 to -4.6. Such isotopic compositions are distinct from asthenospheric signatures and most likely probe the lower lithosphere. Sm-Nd model age and trace element data for the Yunnan lavas indicate that at the time of eruption the mantle source was an old ([is greater than] 1 Ga) mica-bearing spinel harzburgite. However, such Proterozoic enriched lithospheric mantle could not have survived the thermo-tectonic processes associated with continental flood volcanism that affected the same part of the western Yangtze craton 250 Ma. Emeishan flood basalt volcanism would have purged the shallow mantle of all its fusible constituents and any enrichments would be younger than 250 Ma. We propose that the lithosphere mantle beneath the western Yangtze craton is exotic and probably represents part of the Tibetan lithosphere extruded to the east 40-50 Ma. The Indo-Asia collision provides a suitable mechanism and explains the link between the west Yangtze craton and northern Tibet in terms of provenance (Sr-Nd) and the similar two-dimensional seismic velocity structure. Keywords: ultrapotassic rocks, lithosphere mantle, metasomatism, Tibet, west Yunnan.

Understanding the subduction-driven recycling of economically important chalcophile metals (e.g., Cu, Au, Ag, and platinum-group elements, PGEs) and volatiles (e.g., sulfur) is critical for assessing models of ore formation. However, whether the sulfide remains stable in recycled altered oceanic crust (AOC) in the mantle is unclear, and the influence of AOC-derived metasomatic agents on the extraction efficiency of chalcophile elements from the deep mantle remains poorly understood. Here we report whole-rock Cu-Ag-Au-Re-PGEs of Cenozoic alkaline basalts at Hannuoba, eastern China, which were derived from the interaction of carbonated eclogite (recycled AOC)-derived melts with lithospheric peridotites. Volatile-rich primitive melts from carbonated eclogite are poor in strongly chalcophile metals (e.g., ∑PGE < 1 ng/g, Au < 1 ng/g, Cu < 30 μg/g). Remarkably, primitive melts show significant fractionation of elements with variable chalcophile affinities, such as lower Cu/Ag ratios than those in primitive mantle and MORBs. These features reflect the sequestration of these metals in residual mono-sulfide solid solution (MSS) during low-degree melting of the AOC in the deep mantle. Given the retention of sulfides in the AOC, partial melts derived from it are rich in sulfur but poor in strongly chalcophile metals. The Hannuoba alkaline melts scavenged some strongly chalcophile metals from peridotites (especially PGEs) during their ascent. However, this did not necessarily lead to the formation of chalcophile metal-enriched melts (e.g., Au < 1 ng/g and Cu < 60 μg/g). These processes appear to be common in eastern China, as evidenced by the low abundances of Cu and Au found in many primitive intraplate alkaline basalts. We propose that strongly chalcophile elements in subducted AOC are efficiently transported into, and stored in, the deep mantle, with a small proportion returning to the exosphere through volcanism. Moreover, the chalcophile metal-poor and volatile-rich melts of subducted AOC could also explain the addition of abundant sulfur (secondary sulfides), but limited chalcophile metals to the metasomatized mantle. [ABSTRACT FROM AUTHOR]

Recently, populations of Rana dybowskii, an important amphibian species in Northeast China, have decreased, mainly owing to the disease caused by Aeromonas hydrophila. However, effective control methods have not yet been developed. In order to explore the immune responses of R. dybowskii upon exposure to A. hydrophila infection, Illumina high-throughput transcriptome sequencing and digital gene expression (DGE) technology were employed to investigate transcriptomic changes in the skin of R. dybowskii exposed to A. hydrophila. In this work, a total of 26,244,446 transcriptome sequencing reads were obtained and assembled into 109,089 unique unigenes using de novo assembly, and a total of 37,105 unigenes (34.0%) were functionally annotated against the non-redundant (Nr), Swiss-Prot, Cluster of Orthologous Groups of Proteins (COG), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) databases. Gene expression changes in the skin tissue of R. dybowskii exposed to A. hydrophila were investigated by a tag-based DGE system, and a total of 1435 significantly differentially expressed genes were identified, including 460 that were up-regulated and 975 that were down-regulated, indicating a large change in the host transcriptome profile exposed to A. hydrophila. Among these, 478 genes were associated with immune-relevant pathways, metabolic pathways, cellular components, growth, migration, and muscle and hormone signaling pathways. We confirmed the differential expression of 106 immune-relevant genes associated with innate and adaptive immune responses. Our data provide a fairly comprehensive molecular biology background for the deeper understanding of the amphibian immune system following A. hydrophila infection. [ABSTRACT FROM AUTHOR]

In this study, a multiplex PCR assay with dual priming oligonucleotide system (DPO system-based mPCR) was developed for the simultaneous detection of Salmonella spp., Listeria ( L.) monocytogenes, Shigella spp., Staphylococcus ( S.) aureus, Campylobacter ( C.) jejuni and Yersinia ( Y.) enterocolitica from food. Pathogen-specific DPO systems were designed targeting Salmonella spp. fimY gene, L. monocytogenes iap gene, Shigella spp. ipaH gene, S. aureus 442 gene, C. jejuni gyrA gene and Y. enterocolitica 16 s- 23 s rRNA gene, respectively. Our optimized DPO system-based mPCR assay allowed a wide range of annealing temperature from 48 to 68 °C to efficiently amplify multi-genes followed by a nearly identical pattern with an analytical detection limit of 10-10 CFU/mL (g) for the simultaneous detection of the six target bacteria in pure cultures or artificially contaminated food matrixes. Applying the DPO system-based mPCR assay to 238 target and 83 nontarget bacterial strains revealed that only target bacterial strains were positive in this assay, indicating a high specificity. Moreover, the DPO system-based mPCR assay showed a potential diagnostic capability evaluated by testing 2419 samples collected from food, clinical and environmental sources. The DPO system-based mPCR assay may provide a useful tool for the detection of these six foodborne pathogens in laboratory diagnosis. [ABSTRACT FROM AUTHOR]

Three Fe-Ti oxide-bearing layered intrusions (Mazaertag, Wajilitag, and Piqiang) in the Tarim large igneous province (NW China) have been investigated for understanding the relationship of sulfide saturation, Platinum-group element (PGE) enrichment, and Fe-Ti oxide accumulation in layered intrusions. These mafic-ultramafic layered intrusions have low PGE concentrations (<0.4 ppb Os, <0.7 ppb Ir, <1 ppb Ru, <0.2 ppb Rh, <5 ppb Pt, and <8 ppb Pd) and elevated Cu/Pd (2.2 × 10 to 3.3 × 10). The low PGE concentrations of the rocks are mainly attributed to PGE-depleted, parental magma that was produced by low degrees of partial melting of the mantle. The least contaminated rocks of the Mazaertag and Wajilitag intrusions have slightly enriched Os isotopic compositions with γ(t = 280 Ma) values ranging from +13 to +23, indicating that the primitive magma may have been generated from a convecting mantle, without appreciable input of lithospheric mantle. The Mazaertag and Wajilitag intrusions have near-chondritic γ(t) values (+13 to +60) against restricted ε (t) values (−0.4 to +2.8), indicating insignificant crustal contamination. Rocks of the Piqiang intrusion have relatively low ε (t) values of −3.1 to +1.0, consistent with ∼15 to 25 % assimilation of the upper crust. The rocks of the Mazaertag and Wajilitag intrusions have positive correlation of PGE and S, pointing to the control of PGE by sulfide. Poor correlation of PGE and S for the Piqiang intrusion is attributed to the involvement of multiple sulfide-stage liquids with different PGE compositions or sulfide-oxide reequilibration on cooling. These three layered intrusions have little potential of reef-type PGE mineralization. Four criteria are summarized in this study to help discriminate between PGE-mineralized and PGE-unmineralized mafic-ultramafic intrusions. [ABSTRACT FROM AUTHOR]

The composition of lower crust of the Tarim Craton in NW China is essential to understand the petrogenesis of the ~290-275 Ma Tarim basalts and associated intermediate-felsic rocks. However, it remains poorly constrained because extremely sparse granulite terrains or granulite xenoliths have been found in the Tarim Craton. New trace element and Sr-Nd-Pb isotopic data are reported for the Neoarchean and Neoproterozoic igneous rocks widely distributed in the northern margin of the Tarim Craton. The Neoarchean granitic gneisses show fractionated REE (rare earth element) patterns [(La/Yb) = 12-58, Yb = 10.6-36] with pronounced negative Nb-Ta and Ti anomalies. These features, together with negative εNd (−0.7 to −3.2) suggest that they were derived from melting of mafic lower crust. The Neoproterozoic biotite granodiorites are strongly depleted in HREE with (La/Yb) up to 55. They are characterized by high Sr (671-789 ppm) but very low Y (7.10-8.06 ppm) and Yb contents (0.47-0.58 ppm), showing typical features of adakitic rocks. The samples with different SiO contents display identical Sr/Sr (0.7101-0.7103), εNd (−14.1 to −15.7) and Pb isotopes (Pb/Pb = 36.94-37.07). These features together with arc-like trace element patterns suggest that they were derived from melting of thickened lower crust. In comparison, the Neoproterozoic hornblende-biotite granodiorites have similar trace element compositions except for weaker depletion in HREE and have lower Sr/Sr (0.7078) and initial Pb isotopes, and higher εNd (−12.3 to −12.7). This suggests that they were formed by melting of old lower continental crust at a shallower depth than the biotite granodiorites. These rocks were derived from the lower crust, thus providing valuable information on the nature of the lower crust beneath northern Tarim. Combined with published data, the Sr/Sr, εNd, Pb/Pb and εHf of the northern Tarim lower crust ranges from 0.7055 to 0.7103, from −12 to −17, from 16.20 to 16.65, and from −7 to −19, respectively, at ~785 Ma. These data also suggest vertical compositional heterogeneity of the northern Tarim lower crust. [ABSTRACT FROM AUTHOR]

We developed a multiplex PCR-based procedure followed by high-performance liquid chromatography (mPCR-HPLC) assay for high-throughput screening foodborne pathogens, including Salmonella spp., Listeria monocytogenes, Enterobacter sakazakii, Staphylococcus aureus, Shigella spp., Escherichia coli O157:H7, Vibrio parahaemolyticus, Vibrio cholerae, and Vibrio vulnificus. Vibrio species-specific primers were designed targeting dnaJ gene, and pathogen-specific primers for L. monocytogenes, Salmonella spp., E. sakazakii, E. coli O157:H7, Shigella spp., and S. aureus were designed targeting iap, fimY, 16S ribosomal RNA ( rRNA), rfbE, ipaH, and 442 genes, respectively. PCR products were analyzed using WAVE-4500 DNA system equipped with PS-DVB-C18 particles DNASep column and each specific amplicon generated a characteristic chromatographic profile. Detection limit of mPCR-HPLC assay was ca. 10 CFU/mL in pure cultures and less than 10 CFU/g in contaminated matrixes. A total of 395 bacterial strains were used for specificity testing of the mPCR-HPLC assay, and specific HPLC profiles were only produced in strains belonging to the target, showing a high specificity. Applying the assay to 2677 samples collected from clinical, food, and environmental sources revealed that 917 samples were positive, in accordance with bacterial isolation. The high sensitivity and specificity of mPCR-HPLC assay indicate its great potential to be a powerful tool for high-throughput screening foodborne pathogens. [ABSTRACT FROM AUTHOR]