iTRAQ‐based proteomic analysis of dioscin on human HCT‐116 colon cancer cells

Dioscin shows various pharmacological effects. However, its activity on colorectal cancer is still unknown. The present work showed that dioscin significantly inhibited cell proliferation on human HCT‐116 colon cancer cells, and affected Ca²⁺ release and ROS generation. The content of nitric oxide (NO) and its producer inducible NO synthase (iNOS) associated with DNA damage and aberrant cell signaling were assayed using the kits. DNA damage and cell apoptosis caused by dioscin were also analyzed through single‐cell gel electrophoresis and in situ terminal deoxynucleotidyl transferase dUTP nick‐end labeling assays. The results showed that dioscin increased the levels of NO and inducible NO synthase. The comet length in dioscin‐treated groups was much longer than that of the control group, and the number of terminal deoxynucleotidyl transferase dUTP nick‐end labeling positive cells (apoptotic cells) was significantly increased by the compound (p < 0.01). Furthermore, dioscin caused mitochondrial damage and G2/M cell cycle arrest through transmission electron microscopy and flow cytometry analysis, respectively. To study the cytotoxic mechanism of dioscin, an iTRAQ‐based proteomics approach was used. There were 288 significantly different proteins expressed in response to dioscin, which were connected with each other and were involved in different Kyoto Encyclopedia of Genes and Genomes pathways. Then, some differentially expressed proteins involved in oxidative phosphorylation, Wnt, p53, and calcium signaling pathways were validated by Western blotting and quantitative real‐time PCR assays. Our work elucidates the molecular mechanism of dioscin‐induced cytotoxicity in colon cancer cells, and the identified targets may be useful for treatment of colorectal cancer in future.     

Estimation of lipase activity by the diffusion plate method

A diffusion plate method for the assay of the activity of lipases in large series of samples was worked out. When using this method the maximum deviation was found to be ±3.8%.     

Deacylation of acetylated amino acids by the esterase fromMycobacterium phlei

In addition to typical acetyl esters, acetic ester aoetyl-hydrolase fromMycobacterium phlei can degrade aliphatic acetylated amino acids under suitable conditions.     

Functional organization of the human auditory cortex

We investigated the functional organization of the human auditory cortex using a novel electrophysiological recording technique combined with an advanced brain magnetic resonance imaging (MRI) technique. Tonotopic mapping data were obtained during single unit recording along the Heschl’s gyrus. Most of the units studied (73%) demonstrated sharply tuned excitatory responses. A tonotopic pattern was observed with the best frequencies systematically increasing as more medial-caudal recording sites were sampled. Additionally, a new auditory field along the posterior aspect of the superior temporal gyrus has been identified using a high spatial resolution direct recording technique. Results obtained during electrical stimulation demonstrate functional connectivity between the primary auditory cortex and the auditory field in the posterior superior temporal gyrus.     

Interaction of aflatoxin B1 with electron-donating organic molecules,including aromatic amino acids

The interaction of the carcinogenic mycotoxin, aflatoxin B₁, with some electrondonating organic compounds including aromatic hydrocarbons, dimethylaniline, and aromatic amino acids, was studied. Spectrophotometric analysis of aflatoxin B₁ revealed that hypochromicity in the absorption around 360 nm and hyperchromicity around 385 nm were induced by dimethylaniline, hexamethylbenzene, tryptophan, and imidazole. A similar shifting of aflatoxin B₁ absorption was observed in benzene, toluene, and xylene in the presence of ZnCl₂. The interaction of aflatoxin B₁ with polystyrene was observed in a biphasic system. The association constants of aflatoxin B₁: DMA⁴ (1:1) and of aflatoxin B₁: tryptophan (1:1) were found to be 0.64 and 22.6 liters per mole, respectively. The results suggest that charge-transfer interaction occurs between aflatoxin B₁ and these π-electron donors. Since the spectral changes on aflatoxin B₁ absorption induced by these π-electron donors are similar to those induced by nucleic acids and proteins, it is postulated that charge-transfer interaction also occurs between aflatoxin B₁ and these macromolecules. The role of such interaction in the biological activity of aflatoxin B₁ is discussed.     

Effect of Elastic Network of Ceramic Fillers on Thermal Cycle Stability of a Solid Oxide Fuel Cell Stack

Glass‐based seals for planar solid‐oxide fuel‐cell (SOFC) stacks are open to uncontrolled deformation and mechanical damages, limiting both sealing integrity and stack reliability, particularly in thermal cycle operations. If the glass‐based seals work like an elastomer‐based compressive seal, SOFC stacks may survive unprecedented numbers of thermal cycles. A novel composite sealing gasket is successfully developed to mimic the unique features of the elastomer‐based compressive seal by controlling the composition and packing behavior of binary ceramic fillers. A single‐cell SOFC stack undergoes more than 100 thermal cycles with little performance loss, during which the sealing integrity is lost/recovered repeatedly upon cooling and reheating, corresponding to unloading/loading of the elastomer‐based compressive seal. The thermal‐cycle responses of the SOFC stack are explained in sequence by the concurrent events of elastic deformation/recovery of ceramic filler network and corresponding redistribution of sealing glass.     

New isolate of Loma psittaca (Microsporidia: Glugeidae) infecting the stomach wall of cultured hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀) in South China

Loma psittaca, previously described as inhabiting the intestinal mucosa of an anadromous fish, Colomesus pisttacus, from the Amazon Basin, is reported as being found for the first time in a marine fish, the hybrid grouper (Epinephelus lanceolatus♂×Epinephelus fuscoguttatus♀), from Lingshui city, Hainan Province, China, expanding the geographical distribution and host range of this parasite. Numerous whitish xenomas (0.5–0.7 mm in diameter) of this new isolate of L. psittaca were found distinctly in the muscle layer of the host stomach wall. Electron microscopic observations showed a monokaryotic nucleus in all developmental stages. Round or elongated multinucleate merogonial plasmodia surrounded by numerous mitochondria were observed initially, subsequently transforming into uninucleate sporonts through multiple fissions. Sporonts, each with a large centrally positioned nucleus, further developed into sporoblasts. Each sporoblast mother cell gave rise to two uninucleate sporoblasts by binary fission. Mature spores were ellipsoidal, measuring 4.0 ± 0.3 (3.7–4.3) μm in length and 2.2 ± 0.2 (2.1–2.5) μm in width. Spores possessed a mushroom-like anchoring disk, a bipartite polarplast, isofilar polar filaments arranged in 12–14 turns in one row, and a trilaminar spore wall. The obtained partial SSU rRNA gene sequence of the new isolate was 1330 bp in length and showed 99.4% sequence similarity with an estuary isolate of L. psittaca previously reported in South America. SSU rRNA gene-based phylogenetic analyses demonstrated that the two L. psittaca isolates first clustered together and then formed a dichotomy that included the digestive-tract-infecting Loma species, L. acerinae, with high support values within group I.     

Muscle-specific transgenic expression of porcine myostatin propeptide enhances muscle growth in mice

Myostatin is a well-known negative regulator of skeletal muscle growth. Inhibition of myostatin activity results in increased muscle mass. Myostatin propeptide, as a myostatin antagonist, could be applied to promote meat production in livestock such as pigs. In this study, we generated a transgenic mouse model expressing porcine myostatin propeptide under the control of muscle-specific regulatory elements. The mean body weight of transgenic mice from a line expressing the highest level of porcine myostatin propeptide was increased by 5.4 % (P = 0.023) and 3.2 % (P = 0.031) in males and females, respectively, at 8 weeks of age. Weight of carcass, fore limb and hind limb was respectively increased by 6.0 % (P = 0.038), 9.0 % (P = 0.014), 8.7 % (P = 0.036) in transgenic male mice, compared to wild-type male controls at the age of 9 weeks. Similarly, carcass, fore limb and hind limb of transgenic female mice was 11.4 % (P = 0.002), 14.5 % (P = 0.006) and 14.5 % (P = 0.03) respectively heavier than that of wild-type female mice. The mean cross-section area of muscle fiber was increased by 17 % (P = 0.002) in transgenic mice, in comparison with wild-type controls. These results demonstrated that porcine myostatin propeptide is effective in enhancement of muscle growth. The present study provided useful information for future study on generation of transgenic pigs overexpressing porcine myostatin propeptide for improvement of muscle mass.