66 research outputs found
In situ Proteomic Profiling of Curcumin Targets in HCT116 Colon Cancer Cell Line
To date, the exact targets and mechanism of action of curcumin, a natural product with anti-inflammatory and anti-cancer properties, remain elusive. Here we synthesized a cell permeable curcumin probe (Cur-P) with an alkyne moiety, which can be tagged with biotin for affinity enrichment, or with a fluorescent dye for visualization of the direct-binding protein targets of curcumin in situ. iTRAQ™ quantitative proteomics approach was applied to distinguish the specific binding targets from the non-specific ones. In total, 197 proteins were confidently identified as curcumin binding targets from HCT116 colon cancer cell line. Gene Ontology analysis showed that the targets are broadly distributed and enriched in the nucleus, mitochondria and plasma membrane, and they are involved in various biological functions including metabolic process, regulation, response to stimulus and cellular process. Ingenuity Pathway Analysis™ (IPA) suggested that curcumin may exert its anticancer effects over multiple critical biological pathways including the EIF2, eIF4/p70S6K, mTOR signaling and mitochondrial dysfunction pathways. Functional validations confirmed that curcumin downregulates cellular protein synthesis, and induces autophagy, lysosomal activation and increased ROS production, thus leading to cell death
Dramatic Improvement of Proteomic Analysis of Zebrafish Liver Tumor by Effective Protein Extraction with Sodium Deoxycholate and Heat Denaturation
Majority of the proteomic studies on tissue samples involve the use of gel-based approach for profiling and digestion. The laborious gel-based approach is slowly being replaced by the advancing in-solution digestion approach. However, there are still several difficulties such as difficult-to-solubilize proteins, poor proteomic analysis in complex tissue samples, and the presence of sample impurities. Henceforth, there is a great demand to formulate a highly efficient protein extraction buffer with high protein extraction efficiency from tissue samples, high compatibility with in-solution digestion, reduced number of sample handling steps to reduce sample loss, low time consumption, low cost, and ease of usage. Here, we evaluated various existing protein extraction buffers with zebrafish liver tumor samples and found that sodium deoxycholate- (DOC-) based extraction buffer with heat denaturation was the most effective approach for highly efficient extraction of proteins from complex tissues such as the zebrafish liver tumor. A total of 4,790 proteins have been identified using shotgun proteomics approach with 2D LC, which to our knowledge is the most comprehensive study for zebrafish liver tumor proteome
A Comparative Proteomic Analysis Reveals a New Bi-Lobe Protein Required for Bi-Lobe Duplication and Cell Division in Trypanosoma brucei
A Golgi-associated bi-lobed structure was previously found to be important for Golgi duplication and cell division in Trypanosoma brucei. To further understand its functions, comparative proteomics was performed on extracted flagellar complexes (including the flagellum and flagellum-associated structures such as the basal bodies and the bi-lobe) and purified flagella to identify new bi-lobe proteins. A leucine-rich repeats containing protein, TbLRRP1, was characterized as a new bi-lobe component. The anterior part of the TbLRRP1-labeled bi-lobe is adjacent to the single Golgi apparatus, and the posterior side is tightly associated with the flagellar pocket collar marked by TbBILBO1. Inducible depletion of TbLRRP1 by RNA interference inhibited duplication of the bi-lobe as well as the adjacent Golgi apparatus and flagellar pocket collar. Formation of a new flagellum attachment zone and subsequent cell division were also inhibited, suggesting a central role of bi-lobe in Golgi, flagellar pocket collar and flagellum attachment zone biogenesis
Potential protein hydrolysates from the white and purple flower varieties of Orthosiphon aristatus leaves
This study was aimed to extract bioactive peptides from the white and purple flower varieties of Orthosiphon aristatus leaves. The herb is well known for its pharmacological importance, possibly attributed to its plant proteins. Phenol based extraction was used to extract plant proteins, and then hydrolysed by proteolytic enzymes such as trypsin (serine protease) and pepsin (aspartic protease). MS/MS analysis revealed that 145 and 125 proteins were detected from the white and purple flower varieties, respectively. Trypsin hydrolysates were showed to have a higher degree of hydrolysis (24–33%), resulting in higher antioxidant and antibacterial activities. The white flower of trypsin hydrolysates showed a higher radical scavenging activity which could be attributed to its higher content of stress proteins (19%). However, trypsin hydrolysates from the purple flower showed higher ferric reducing power and bacterial growth inhibition. The performance of hydrolysates was better than ampicillin in inhibiting Acinetobacter baumanni and Staphylococcus aureus
White Spot Syndrome Virus Proteins and Differentially Expressed Host Proteins Identified in Shrimp Epithelium by Shotgun Proteomics and Cleavable Isotope-Coded Affinity Tag▿ †
Shrimp subcuticular epithelial cells are the initial and major targets of white spot syndrome virus (WSSV) infection. Proteomic studies of WSSV-infected subcuticular epithelium of Penaeus monodon were performed through two approaches, namely, subcellular fractionation coupled with shotgun proteomics to identify viral and host proteins and a quantitative time course proteomic analysis using cleavable isotope-coded affinity tags (cICATs) to identify differentially expressed cellular proteins. Peptides were analyzed by offline coupling of two-dimensional liquid chromatography with matrix-assisted laser desorption ionization-tandem time of flight mass spectrometry. We identified 27, 20, and 4 WSSV proteins from cytosolic, nuclear, and membrane fractions, respectively. Twenty-eight unique WSSV proteins with high confidence (total ion confidence interval percentage [CI%], >95%) were observed, 11 of which are reported here for the first time, and 3 of these novel proteins were shown to be viral nonstructural proteins by Western blotting analysis. A first shrimp protein data set containing 1,999 peptides (ion score, ≥20) and 429 proteins (total ion score CI%, >95%) was constructed via shotgun proteomics. We also identified 10 down-regulated proteins and 2 up-regulated proteins from the shrimp epithelial lysate via cICAT analysis. This is the first comprehensive study of WSSV-infected epithelia by proteomics. The 11 novel viral proteins represent the latest addition to our knowledge of the WSSV proteome. Three proteomic data sets consisting of WSSV proteins, epithelial cellular proteins, and differentially expressed cellular proteins generated in the course of WSSV infection provide a new resource for further study of WSSV-shrimp interactions
Business study mission to Mexico manufacturing sector.
A duopoly exists in the Mexican tobacco market, with two very big firms Cigatam and CLM monopolising the market. It would be difficult to enter a market with two big players deeply entrenched and consumers becomingly price-sensitive, unless a new entrant has a way to achieve economies of scale. There should be opportunities, though, for foreign companies wishing to strike up alliance or joint ventures through either brand sharing or asset sharing with the two big existing players.Master of Business Administratio
High-Performance Graphene-Titania Platform for Detection of Phosphopeptides in Cancer Cells
Phosphopeptides play a crucial role in many biological processes and constitute some of the most powerful biomarkers in disease detection. However they are often present in very low concentration, which makes their detection highly challenging. Here, we demonstrate the use of a solution-dispersible graphene-titania platform for the selective extraction of phosphopeptides from peptide mixtures. This is followed by direct analysis by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The efficient charge and energy exchange between graphene and TiO2 during laser irradiation in SELDI-TOF MS promotes the soft ionization of analytes and affords a detection limit in the attomole range, which is 10(2)-10(5) more sensitive than conventional platforms. The graphene-titania platform can also be used for detecting phosphopeptides in cancer cells (HeLa cells), where it shows high specificity (94%). An expanded library of 967 unique phosphopeptides is detected using significantly reduced loading of extraction matrixes compared to conventional TiO2 bead-based assays.close1
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