Source Apportionment of Trace Element Pollution in Surface Sediments Using Positive Matrix Factorization Combined Support Vector Machines: Application to the Jinjiang River, China

In this study, a method of positive matrix factorization (PMF) combined support vector machines (SVMs) was adopted to identify possible sources and apportion contributions for trace element pollution in surface sediments from the Jinjiang River, Southeastern China. Utilizing diagnostics tools, four significant factors were extracted from sediment samplers, which were collected in December 2010 at 15 different sites. By treating source identification as a pattern recognition problem, the factor loadings derived from PMF were classified by SVM classifiers which have been trained and validated with fingerprints of eight potential source categories. Using SVM, industrial wastewater from lead ore mining and metal handcraft manufacture, atmospheric deposition, and natural background were identified as main sources of trace element pollution in surface sediments from the Jinjiang River, which were affirmed by visually comparing compound patterns and the differences between the predicted and actual fractional compositions. Apportionment results showed that source of lead ore mining made the largest contribution (33.62 %), followed by atmospheric deposition (30.99 %), metal handcraft manufacture (30.09 %), and natural background (5.29 %).     

S‐nitrosylated protein disulfide isomerase contributes to mutant SOD1 aggregates in amyotrophic lateral sclerosis

A major hallmark of mutant superoxide dismutase (SOD1)‐linked familial amyotrophic lateral sclerosis is SOD1‐immunopositive inclusions found within motor neurons. The mechanism by which SOD1 becomes aggregated, however, remains unclear. In this study, we aimed to investigate the role of nitrosative stress and S‐nitrosylation of protein disulfide isomerase (PDI) in the formation of SOD1 aggregates. Our data show that with disease progression inducible nitric oxide synthase (iNOS) was up‐regulated, which generated high levels of nitric oxide (NO) and subsequently induced S‐nitrosylation of PDI in the spinal cord of mutant SOD1 transgenic mice. This was further confirmed by in vitro observation that treating SH‐SY5Y cells with NO donor S‐nitrosocysteine triggered a dose‐dependent formation of S‐nitrosylated PDI. When mutant SOD1 was over‐expressed in SH‐SY5Y cells, the iNOS expression was up‐regulated, and NO generation was consequently increased. Furthermore, both S‐nitrosylation of PDI and the formation of mutant SOD1 aggregates were detected in the cells expressing mutant SOD1^G93A. Blocking NO generation with the NOS inhibitor N‐nitro‐l ‐arginine attenuated the S‐nitrosylation of PDI and inhibited the formation of mutant SOD1 aggregates. We conclude that NO‐mediated S‐nitrosylation of PDI is a contributing factor to the accumulation of mutant SOD1 aggregates in amyotrophic lateral sclerosis.     

Molecular cloning and characterization of the mitogen-activated protein kinase kinase gene (MKK4) and its promoter sequence from oilseed rape (Brassica campestris L.)

Mitogen-activated protein kinase (MAPK) cascades are involved in various processes, including plant growth and development as well as biotic and abiotic stress responses. MAPK kinases (MKKs), which link MPKs and MAPKK kinases (MKKKs), are crucial in MAPK cascades because these kinases mediate various stress responses in plants. However, only few MKKs in Brassica campestris (rape) have been functionally characterized. In this study, a novel gene, MKK4 that belongs to a C MKK group, was isolated and characterized from rape. Bioinformatics analysis revealed that the length of cDNA was 1,317 bp with an open reading frame of 993 bp, which encodes a polypeptide containing 330 amino acids, including a putative signal peptide with 27 amino acid residues and a mature protein with 303 amino acids. The obtained MKK4 exhibited a predicted molecular mass of 36.5 kDa and an isoelectric point of 9.01. Quantitative real-time polymerase chain reaction analysis revealed that MKK4 expression could be induced by cold and salt. We also found that the MKK4 protein is localized in the nucleus. In addition, a 999 bp promoter fragment of MKK4 was cloned. Sequence analysis revealed that several putative regulatory elements were found in the MKK4 promoter. Transient expression assay showed that the MKK4 promoter fragments exhibited promoter activity and stimulated GFP expression. The effects of GFP gene expression at different temperatures and in different onion epidermis culture patterns were compared. Results showed that the MKK4 promoter could respond to low temperature and salt stress. These results suggested that MKK4 is possibly important for the regulation of cold- and salt-stress responses in plants.     

Design, expression, and characterization of a novel targeted plectasin against methicillin-resistant Staphylococcus aureus

A novel specifically targeted antimicrobial peptide (STAMP) that was especially effective against methicillin-resistant Staphylococcus aureus (MRSA) was designed by fusing the AgrD1 pheromone to the N-terminal end of plectasin. This STAMP was named Agplectasin, and its gene was synthesized and expressed in Pichia pastoris X-33 via pPICZαA. The highest amount of total secreted protein reached 1,285.5 mg/l at 108 h during the 120-h induction. The recombinant Agplectasin (rAgP) was purified by cation exchange chromatography and hydrophobic exchange chromatography; its yield reached 150 mg/l with 94 % purity. The rAgP exhibited strong bactericidal activity against S. aureus but not Staphylococcus epidermidis or other types of tested bacteria. A bactericidal kinetics assay showed that the rAgP killed over 99.9 % of tested S. aureus (ATCC 25923 and ATCC 43300) in both Mueller–Hinton medium and human blood within 10 h when treated with 4× minimal inhibitory concentration. The rAgP caused only approximately 1 % hemolysis of human blood cells, even when the concentration reached 512 μg/ml, making it potentially feasible as a clinical injection agent. In addition, it maintained a high activity over a wide range of pH values (2.0–10.0) and demonstrated a high thermal stability at 100 °C for 1 h. These results suggested that this STAMP has the potential to eliminate MRSA strains without disrupting the normal flora.     

Top-down motif engineering of a cytokine receptor for directing ex vivo expansion of hematopoietic stem cells

The technique to expand hematopoietic stem cells (HSCs) ex vivo is eagerly anticipated to secure an enough amount of HSCs for clinical applications. Previously we developed a scFv-thrombopoietin receptor (c-Mpl) chimera, named S-Mpl, which can transduce a proliferation signal in HSCs in response to a cognate antigen. However, a remaining concern of the S-Mpl chimera may be the magnitude of the cellular expansion level driven by this molecule, which was significantly less than that mediated by endogenous wild-type c-Mpl. In this study, we engineered a tyrosine motif located in the intracellular domain of S-Mpl based on a top-down approach in order to change the signaling properties of the chimera. The truncated mutant (trunc.) and an amino-acid substitution mutant (Q to L) of S-Mpl were constructed to investigate the ability of these mutants to expand HSCs. The result showed that the truncated and Q to L mutants gave higher and considerably lower number of the cells than unmodified S-Mpl, respectively. The proliferation level through the truncated mutant was even higher than that of non-transduced HSCs with the stimulation of a native cytokine, thrombopoietin. Moreover, we analyzed the signaling properties of the S-Mpl mutants in detail using a pro-B cell line Ba/F3. The data indicated that the STAT3 and STAT5 activation levels through the truncated mutant increased, whereas activation of the Q to L mutant was inhibited by a negative regulator of intracellular signaling, SHP-1. This is the first demonstration that a non-natural artificial mutant of a cytokine receptor is effective for ex vivo expansion of hematopoietic cells compared with a native cytokine receptor.     

鱼类分批繁殖力和繁殖频率的研究进展

繁殖潜力是决定鱼类的繁殖补充及制定种群评估生物学假设的关键机制,由此分批繁殖力和繁殖频率对评估分批繁殖鱼类的繁殖潜力就十分必要.分批繁殖力和繁殖频率的研究均开始于20世纪80年代,在过去的30年中,评估分批繁殖力最为广泛使用的方法是水化卵法,而繁殖频率使用最多的方法是产后滤泡法.这两种方法虽然都存在一定的不足,但无可否认是现在最为实用和成熟的方法.     

MST1 activation by curcumin mediates JNK activation,Foxo3a nuclear translocation and apoptosis in melanoma cells

Different groups including ours have shown that curcumin induces melanoma cell apoptosis, here we focused the role of mammalian Sterile 20-like kinase 1 (MST1) in it. We observed that curcumin activated MST1-dependent apoptosis in cultured melanoma cells. MST1 silencing by RNA interference (RNAi) suppressed curcumin-induced cell apoptosis, while MST1 over-expressing increased curcumin sensitivity. Meanwhile, curcumin induced reactive oxygen species (ROS) production in melanoma cells, and the ROS scavenger, N-acetyl-cysteine (NAC), almost blocked MST1 activation to suggest that ROS might be required for MST1 activation by curcumin. c-Jun N-terminal protein kinase (JNK) activation by curcumin was dependent on MST1, since MST1 inhibition by RNAi or NAC largely inhibited curcumin-induced JNK activation. Further, curcumin induced Foxo3 nuclear translocation and Bim-1 (Foxo3 target gene) expression in melanoma cells, such an effect by curcumin was inhibited by MST1 RNAi. In conclusion, we suggested that MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells.     

Evidence for Tissue-Specific JAK/STAT Target Genes in Drosophila Optic Lobe Development

The evolutionarily conserved JAK/STAT pathway plays important roles in development and disease processes in humans. Although the signaling process has been well established, we know relatively little about what the relevant target genes are that mediate JAK/STAT activation during development. Here, we have used genome-wide microarrays to identify JAK/STAT targets in the optic lobes of the Drosophila brain and identified 47 genes that are positively regulated by JAK/STAT. About two-thirds of the genes encode proteins that have orthologs in humans. The STAT targets in the optic lobe appear to be different from the targets identified in other tissues, suggesting that JAK/STAT signaling may regulate different target genes in a tissue-specific manner. Functional analysis of Nop56, a cell-autonomous STAT target, revealed an essential role for this gene in the growth and proliferation of neuroepithelial stem cells in the optic lobe and an inhibitory role in lamina neurogenesis.