Long non-coding RNA Linc00152 is involved in cell cycle arrest,apoptosis, epithelial to mesenchymal transition,cell migration and invasion in gastric cancer

Gastric cancer remains a serious threat to public health with high incidence and mortality worldwide. Accumulating evidence demonstrates that long non-coding RNAs (lncRNAs) play important roles in regulating gene expression and are involved in various pathological processes, including gastric cancer. To investigate the possible role of dysregulated lncRNAs in gastric cancer development, we performed lncRNA microarray and identified 3141 significantly differentially expressed lncRNAs in gastric cancer tissues. Next, some of deregulated lncRNAs were validated among about 60 paired gastric cancer specimens such as Linc00261, DKFZP434K028, RPL34-AS1, H19, HOTAIR and Linc00152. Our results found that the decline of DKFZP434K028 and RPL34-AS1, and the increased expression of Linc00152 positively correlated with larger tumor size. The high expression levels of HOTAIR were associated with lymphatic metastasis and poor differentiation. Since the biological roles of Linc00152 are largely unknown in gastric cancer pathogenesis, we assessed its functions by silencing its up-regulation in gastric cancer cells. We found that Linc00152 knockdown could inhibit cell proliferation and colony formation, promote cell cycle arrest at G1 phase, trigger late apoptosis, reduce the epithelial to mesenchymal transition (EMT) program, and suppress cell migration and invasion. Taken together, we delineate the gastric cancer lncRNA signature and demonstrate the oncogenic functions of Linc00152. These findings may have implications for developing lncRNA-based biomarkers for diagnosis and therapeutics for gastric cancer.     

Administration of progranulin (PGRN) triggers ER stress and impairs insulin sensitivity via PERK-eIF2α-dependent manner

Progranulin (PGRN) has recently emerged as an important regulator for glucose metabolism and insulin sensitivity. However, the direct effects of PGRN in vivo and the underlying mechanisms between PGRN and impaired insulin sensitivity are not fully understood. In this study, mice treated with PGRN for 21 d exhibited the impaired glucose tolerance and insulin sensitivity, remarkable ER stress as well as attenuated insulin signaling in liver and adipose tissue but not in skeletal muscle. Furthermore, treatment of mice with phenyl butyric acid (PBA), a chemical chaperone alleviating ER stress, resulted in a significant restoration of systemic insulin sensitivity and recovery of insulin signaling induced by PGRN. Consistent with these findings in vivo, we also observed that PGRN treatment induced ER stress, impaired insulin signaling in cultured hepatocytes and adipocytes, with such effects being partially nullified by blockade of PERK. Whereas PGRN-deficient hepatocytes and adipocytes were more refractory to palmitate-induced insulin resistance, indicating the causative role of the PERK-eIF2α axis of the ER stress response in action of PGRN. Collectively, our findings supported the notion that PGRN is a key regulator of insulin resistance and that PGRN may mediate its effects, at least in part, by inducing ER stress via the PERK-eIF2α dependent pathway.     

Suppression of intestinal inflammation and inflammation-driven colon cancer in mice by dietary sphingomyelin: importance of peroxisome proliferator-activated receptor γ expression

Inflammation of the gastrointestinal tract increases the risk of developing colon cancer especially in younger adults. Dietary compounds are not only associated with the etiology of inflammation and colon cancer but also in their prevention. Sphingolipid metabolites have been shown to play a role in the initiation and perpetuation of inflammatory responses. In the present study, we investigated the suppression of dextran sodium sulfate-induced colitis and azoxymethane-induced colon cancer by dietary sphingomyelin (SM) in mice that lack functional peroxisome proliferator-activated receptor γ (PPAR-γ) in intestinal epithelial and immune cells. Dietary SM decreased disease activity and colonic inflammatory lesions in mice of both genotypes but more efficiently in mice expressing PPAR-γ. The increased survival and suppression of tumor formation in the SM-fed mice appeared to be independent of PPAR-γ expression in immune and epithelial cells. Using a real-time polymerase chain reaction array, we detected an up-regulation in genes involved in Th1 (interferon γ) and Th17 (interleukin [IL]-17 and IL-23) responses despite the reduced inflammation scores. However, the genes involved in Th2 (IL-4, IL-13 and IL-13ra2) and Treg (IL-10rb) anti-inflammatory responses were up-regulated in a PPAR-γ-dependent manner. In line with the PPAR-γ dependency of our in vivo findings, treatment of RAW macrophages with sphingosine increased the PPAR-γ reporter activity. In conclusion, dietary SM modulated inflammatory responses at the early stages of the disease by activating PPAR-γ, but its anticarcinogenic effects followed a PPAR-γ-independent pattern.     

Highly-sensitive organophosphorous pesticide biosensors based on nanostructured films of acetylcholinesterase and CdTe quantum dots

The optical transducer of CdTe semiconductor quantum dots (QDs) has been integrated with acetylcholinesterase enzyme (AChE) by the layer-by-layer (LbL) assembly technique, resulting in a highly sensitive biosensor for detection of organophosphorus pesticides (OPs) in vegetables and fruits based on enzyme inhibition mechanism. The detection limits of the proposed biosensors are as low as 1.05 × 10(-11) M for paraoxon and 4.47 × 10(-12) M for parathion, which are significantly better than those of the conventional GC/MS methods or amperometric biosensors (0.5 nM). These biosensors are used for quick determination of low concentrations of OPs in real vegetable and fruit samples and exhibit satisfactory reproducibility and accuracy. Moreover, the stock stability of the biosensors are very good due to the stabilizing environment for the enzyme in the nanostructures made by LbL technique. Many advantages provided by these biosensors, like fluorescent change recognized by naked eyes and mass production with low cost, will facilitate future development of rapid and high-throughput screening of OPs.     

A novel nitrite biosensor based on single-layer graphene nanoplatelet-protein composite film

A novel nitrite biosensor was developed through a sensing platform consisted of single-layer graphene nanoplatelet (SLGnP)-protein composite film. SLGnP with the virtues of excellent biocompatibility, conductivity and high sensitivity to the local perturbations can provide a biocompatible microenvironment for protein immobilization and a suitable electron transfer distance between electroactive centers of heme protein and electrode surface. A pair of well-defined and quasi-reversible cyclic voltammetric peaks that reflected the direct electrochemistry for ferric/ferrous couple of myoglobin (Mb) was achieved at the composite film modified electrode. Field emission scanning electron microscopy (FESEM) and ultraviolet visible spectra (UV-vis) were utilized to characterize the composite film. The results demonstrated that the morphology of the composite film was unique and the protein in the composite film retained its secondary structure similar to the native state. The composite film also displayed excellent electrocatalytic ability for the reduction of nitric oxide, which was applied to determine nitrite indirectly. It exhibited good electrochemical response to nitrite with a linear range from 0.05 to 2.5 mM and a detection limit of 0.01 mM.     

Male gametophyte defective 4 encodes a rhamnogalacturonan II xylosyltransferase and is important for growth of pollen tubes and roots in Arabidopsis

In flowering plants, the growth of pollen tubes is essential for the delivery of sperm to the egg cells. Although many factors (including cell‐wall properties) are involved in this process, little is known about the underlying molecular mechanisms that regulate the growth of pollen tubes. We report here the characterization of an Arabidopsis mutant male gametophyte defective 4 (mgp4) that is severely defective in pollen tube growth. The mgp4 mutation also impairs root growth of pollen‐rescued mgp4 mutant plants generated by expressing MGP4 cDNA under the control of a pollen grain/tube‐specific promoter. The MGP4 gene encodes a putative xylosyltransferase and is expressed in many organs/tissues, including pollen tubes and roots. MGP4 protein expressed in Pichia pastoris exhibited xylosyltransferase activity and transferred d ‐xylose onto l ‐fucose. The pectic polysaccharide rhamnogalacturonan II (RG‐II), isolated from 7‐day‐old pollen‐rescued mutant seedlings, exhibited a 30% reduction in 2‐O‐methyl d ‐xylose residues. Furthermore, an exogenous supply of boric acid enhanced RG‐II dimer formation and partially restored the root growth of the pollen‐rescued mutant seedlings. Taken together, these results suggest that MGP4 plays important roles in pollen tube and root growth by acting as a xylosyltransferase involved in the biosynthesis of pectic RG‐II.     

Efficient gene disruption in Saccharomyces cerevisiae using marker cassettes with long homologous arms prepared by the restriction-free cloning strategy

Here we report an improved method for targeted gene disruption with high efficiency in S. cerevisiae, where the selection markers with long homologous arms are defined by the choice of the primer binding sites at the target locus and the disruption cassettes are constructed by restriction-free (RF) cloning strategy. Three genes, SAM1, IDH1 and IDH2, were disrupted with this method and the disruption efficiencies of SAM1 was improved several folds with much lower false-positive rates compared to the conventional one-step PCR-based gene disruption method. This approach for gene disruption cassettes construction with long flanking homologous arms may be readily applicable to facilitate targeted gene disruption in other non-conventional yeasts and fungi.     

A thermotolerant and cold-active mannan endo-1,4-β-mannosidase from Aspergillus niger CBS 513.88: Constitutive overexpression and high-density fermentation in Pichia pastoris

The mannan endo-1,4-β-mannosidase gene man26A from Aspergillus niger CBS 513.88 was optimized according to the codon usage bias in Pichia pastoris and synthesized by splicing overlap extension PCR. It was successfully expressed in P. pastoris using constitutive expression vector pGAPzαA. The recombinant endo-beta-1,4-mannanase could work in an extremely board temperature range and over 30% relative activity were retained in the temperature range of 5-60 °C. The optimal pH value and temperature for activity were 5.0 and 45 °C, respectively. It was highly thermotolerant with a half-life time of 15 min at 90 °C. A novel fed-batch strategy was developed successfully for high cell-density fermentation and mannanase activity reached 5069 U/mL after cultivation for 56 h in 50 L fermenter. The broad working temperature range, high thermotolerance and efficient expression made this enzyme possible to be applied in food, animal feed and the production of biofuels.     

Model-based predictions of anaerobic digestion of agricultural substrates for biogas production

A modified Anaerobic Digestion Model No. 1 (ADM1), calibrated on a laboratory digester with a feeding mix of 30% weight of cow manure and 70% weight of corn silage, was implemented, showing its performances of simulation as a decision-making and planning-supporting tool for the anaerobic digestion of agricultural substrates. The virtual fermenter obtained was used to conduct simulations with different feeding compositions and loading rates of cow manure, corn silage, grass silage and rape oil. All simulations were started at the same initial state which was represented by a steady state with an organic loading rate of 2.5 kg ODM/(). The effects of the different feeding combinations on biogas composition and biogas yield were predicted reasonably, and partly verified with the available literature data. Results demonstrated that the simulations could be helpful for taking decisions on agricultural biogas plant operation or experimental set-ups, if used advisedly.     

Profiles of photosynthetic glycerolipids in three strains of <Emphasis Type="Italic">Skeletonema</Emphasis> determined by UPLC-Q-TOF-MS

An exhaustive qualitative and quantitative profiling of the photosynthetic glycerolipids in three strains of the marine diatom Skeletonema sp. was carried out by ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry. In the diatom thylakoid membrane, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) account for about 45–70% and 5–15% of the total membrane lipids, respectively. The anionic sulfoquinovosyldiacylglycerol (SQDG) as well as the likewise anionic phosphatidylglycerol (PG) contribute between 10–40% and 4–10% each. The predominant species of MGDG were those with C_16:3/C_16:3, C_20:5/_16:1, and C_20:5/C_16:3. Three main molecular species of DGDG contained C_20:5/C_16:1, C_20:5/C_16:2, and C_16:1/C_16:1. The major molecular species of SQDG were those containing combinations of C_14:0/C_14:0, C_14:0/C_16:0, C_14:0/C_16:1, and C_14:0/C_16:3. All the PG classes contained the C_18:1/C_18:1 as the main molecular species. Based on the fatty acid species in sn-2 position, it is indicated that MGDG and DGDG are biosynthesized through prokaryotic pathway exclusively within the chloroplast, whereas PG and SQDG have a typical mixed biosynthetic pathway (both prokaryotic pathway and eukaryotic pathways). The chemical characteristics of photosynthetic glycerolipids related with ecological physiology are discussed.