Preservation of molecular fossils in carbonate concretions in cretaceous shales in the songliao basin, northeast China

Paleoenvironmental information is better preserved in carbonate concretions. In this study, carbonate concretions in the Cretaceous Nenjiang shale, Songliao Basin, were examined to determine whether molecular fossils reflective of the paleoenvironment were better preserved at these sites. Organic and inorganic geochemical characteristics of the concretions and surrounding rocks were analyzed using a series of techniques, including SEM, LA-ICP-MS, GC-MS-MS, and GC-IRMS. The concretions are composed of high content microcrystalline dolomite. The δ13Ccarb and δ18Ocarb values of the concretionary dolomite were significantly higher than those of the surrounding rocks. The dolomite show enrichment in the LREEs and have a negative Eu anomaly. The concretion biomarkers showed distribution characteristics similar to those of surrounding rocks. This suggested that the molecular fossils preserved in concretions were mainly inherited from surrounding rocks. However, the concretions contained more C27 sterane and hopanes, with the hopane/sterane ratio being significantly higher than that of surrounding rocks (1.49 v. 0.86). Moreover, the relative content of 2-methylhopane was 2.4–6.6 times that of the surrounding rocks. This indicated changes in the biological equilibrium of source organisms within and outside the concretions. It was possible that the unstable organic matter at the core increased the bacterial concentration and activity inside the concretions. Both the hydrogen index and biomarker-derived indicators implied that the transformation of organic matter in concretions was minimized when compared with their host rock. The isotope δ13C16-30 was 1‰–3‰ more prevalent in individual N-alkane hydrocarbons in the concretions than in surrounding rocks, likely owing to differences in lithology, bacterial action, and degree of weathering. The study concluded that carbonate concretions could preserve molecular fossils better than the surrounding rocks, and the in-depth organic geochemical analysis of concretions could provide a valuable reference for research into early life forms

SPARC fusion protein induces cellular adhesive signaling.

Secreted protein, acidic and rich in cysteine (SPARC) has been described as a counteradhesive matricellular protein with a diversity of biological functions associated with morphogenesis, remodeling, cellular migration, and proliferation. We have produced mouse SPARC with a FLAG-tag at the N-terminus of SPARC (Flag-SPARC, FSP) in a Bac-to-Bac baculoviral expression system. After affinity purification, this procedure yields SPARC of high purity, with an electrophoretic mobility of ∼44 kDa under reducing conditions, and ∼38-39 kDa under non-reducing conditions. Unexpectedly, FSP adsorbed to plastic supported cell attachment and spreading, in a calcium-dependent manner. The adhesive activity of native FSP was inhibited by prior incubation with anti-SPARC IgG. Cell adhesion to FSP induced the formation of filopodia and lamellipodia but not focal adhesions that were prominent on cells that were attached to fibronectin. In addition, FSP induced the tyrosine phosphorylation of FAK and paxillin in attached epithelial cells. Erk1/2 and Rac were also activated in cells attached to FSP, but at a lower level in comparison to cells on fibronectin. This study provides new insight into the biological functions of SPARC, a matricellular protein with important roles in cell-extracellualr matrix interactions

Femtosecond laser machining characteristics in a single-crystal superalloy

Femtosecond laser machining characteristics of a nickel-base single-crystal superalloy were investigated as a function of laser fluence and the number of laser pulses. The significant decrease of recast layer for femtosecond laser machining was observed compared with that for nanosecond laser machining. The ablation thresholds for 1, 10, and 100 femtosecond pulse exposure were measured. Two ablation regions of the ablated crater were observed. The change of the ablation diameter and depth depended on the laser fluence and the number of laser pulses. And higher laser fluence could enable a faster rate of laser-machining

Human Adipose Mesenchymal Stem Cells Show More Efficient Angiogenesis Promotion on Endothelial Colony-Forming Cells than Umbilical Cord and Endometrium

Angiogenesis is a complicated process in which perivascular cells play important roles. Multipotent mesenchymal stem/stromal cells (MSCs) from distinct tissues have been proved to be proangiogenic and share functional properties and gene expression profiles with perivascular cells. However, different tissues derived MSCs may exhibit different potential for clinical applications. Accordingly, comparative studies on different MSCs are essential. Here, we characterized MSCs from adipose (ADSCs), umbilical cord (UCMSCs), and endometrium (EMSCs) in terms of the surface antigen expression, differentiation ability, and the ability of angiogenesis promotion on endothelial colony-forming cells (ECFCs) both in vitro and in vivo. No significant differences in immunophenotype and differentiation were observed. In addition, three types of MSCs all located around tubular-like structures formed by ECFCs in coculture system on matrigel. But ECFCs seeded on ADSCs monolayer formed more organized capillary-like network than that on UCMSCs or EMSCs. When suspended with ECFCs in matrigel and implanted into nude mice, ADSCs promoted more functional vessel formation after 7 days. Moreover, in murine hindlimb ischemia model, cotransplantation of ECFCs with ADSCs was significantly superior to UCMSCs and EMSCs in promoting perfusion recovery and limb salvage. Furthermore, ADSC-conditioned medium (CM) contained more proangiogenic factors (such as vascular endothelial growth factor-A, platelet-derived growth factor BB, and basic fibroblast growth factor) and less inhibitory factor (such as thrombospondin-1), when compared with UCMSC-CM and EMSC-CM. And ADSC-CM more durably stabilized the vascular-like structures formed by ECFCs on matrigel and promoted ECFCs migration more efficiently. In summary, MSCs from adipose show significantly efficient promotion on angiogenesis both in vitro and in vivo than UCMSCs and EMSCs. Hence, ADSCs may be recommended as a more suitable source for treating hindlimb ischemia

FSP supports mLEC attachment and spreading in a concentration-dependent manner.

<p>(A) BSA (10 ul/ml), (B) rhSPARC (10 ug/ml), (C–G) FSP (5, 10, 20, 30, 40 ug/ml, respectively), and (H) FSP (10 ug/ml) were preincubated with anti-SPARC IgG (30 ug/ml) at 37°C for 30 min prior to the coating. The proteins were coated onto wells overnight at 4°C. mLECs were plated into each well in serum-free DMEM, and allowed to attach for 2 hr at 37°C. Phase-contrast photomicrographs were taken on the 96-well plates under an inverted microscope equipped with a digital camera. Scale bar = 50 um for all photographs.</p

FSP induces the formation of actin stress fibers, filopodia, and lamellipodia.

<p>Serum-starved cells were plated on coverslips coated with FSP (<b>A</b>), Fn (<b>B</b>), or BSA (<b>C</b>) for 3 hr at 37°C. Cells were immunostained for paxillin, and were counterstained with phalloidin green. Paxillin was localized in filopodia formed in the cells spreading on the FSP substrate. Scale bar = 8 um for all photographs.</p

FSP supports cell attachment and spreading.

<p>BSA, FSP, and Fn were coated onto wells overnight at 4°C. mLEC, hLEC, murine fibroblasts (FB), and BAE cells were plated into each well in serum-free DMEM, and allowed to attach for 2 hr at 37°C. Cells were stained with 0.1% crystal violet, and representative photographs are shown of cells on each substrate. Cell attachment was also quantified by a colorimetric assay (right panel). The absorbance at 562 nm was correlated directly with the number of cells bound to the substrate. <i>Bars</i> represent the mean +/− SD of three experiments carried out in triplicate. *<i>P</i><0.05; NS, not significant. Scale bar = 50 um for all photographs.</p