Human tumor suppressor gene beclin 1 regulates cell growth through autophagy. The mRNA expression of beclin 1 was reported to be down-regulated in breast cancer with high frequency of loss of heterozygosity (LOH). However, there was no report about the expression levels or the regulatory mechanisms of beclin 1 in gastric and colorectal cancer. Both the mRNA and protein expression levels of beclin 1 was detected in the tissues of gastric and coiorectai cancers, as well as the aberrant DNA methylation and LOH related to the expression of beclin 1. By comparing with normal tissues adjacent to the tissue of these tumors, it was found that beclin 1 mRNA expression levels were significantly decreased in gastric tumor tissue. Furtherly by explorating the 5' region of beclin 1 gene sequence, a large and dense CpG island was discovered and meanwhile methylations in the promoter and the intron 2 regions of beclin 1 were found in both gastric and colorectal tumors. And LOH was found in gastric tumors. These findings suggested that aberrant DNA methylation, as well as LOH, were involved in the regulation of beclin 1 expression in gastric and colorectal cancer.

In order to study the effects and the possible mechanisms of Daxx overexpressed in HepG2 to hydrogen peroxide treatment, and to search new targets for cancer chemotherapy, HepG2cells were transfected using lipofectamine 2000, and selected by treatment with G418. Stable cell lines were confirmed by reverse transeriptase polymerase chain reaction (RT-PCR) targeting vector gene. Experiments include the following groups: (1) control group (non-transfected cells); (2) transfected with empty vector (HepG2/GFP cells); and (3) transfected with pEGFP-C1-Daxx (HepG2/GFP-Daxx cells). After incubation with hydrogen peroxide (H2O2) for 24 h, cellular viability was analyzed by MTT, and cellular apoptosis was measured by flow cytometric analysis. Gene expression at protein level was detected by Western blot. The RT-PCR results showed that Daxx RNA in cells transfected with pEGFP-C1-Daxx was increased significantly compared with that in the HepG2/GFP cells. Fluorescence microscopy revealed that Daxx protein was localized in the nuclei. Hydrogen peroxide was used to induce apoptosis of HepG2 cells and observed that the hydrogen peroxide decreased the viability of HepG2 cells in concentration-dependent pattern. The IC50 values in three groups (Normal cells, HepG2/GFP cells and HepG2/GFP-Daxx cells) were 0.72, 0.76, and 0.49 mmol/L respectively. The apoptotic ratio was significantly higher in HepG2/GFP-Daxx cells as compared to the other two groups. HepG2/GFP-Daxx cell incubated with hydrogen peroxide, showed a significant increase in the activation of caspase-3 and JNK as compare with the other groups. Over-expression of Daxx facilitated HepG2 cells apoptosis induced by hydrogen peroxide. Furthermore, there may be a synergetic relation with apoptosis and increase of JNK activity.

Accurate prediction of the translation initiation site (TIS) is an important issue for prokaryotic genome annotation. However, it is still a challenge for the existing methods to predict the TIS in the genomes over a wide variety of GC content. Besides, the existing methods have not yet undergone a comprehensive evaluation, leaving prediction reliability as a largely open problem. A new algorithm MED-StartPlus, a tool that predicts TIS in prokaryotic genomes with a wide variety of GC content was presented. It makes several efforts to model the nucleotide composition bias, the regulatory motifs upstream of the TIS, the sequence patterns around the TIS, and the operon structure. Tests on hundreds of reliable data sets, with TISs confirmed by experiments or having annotated functions, show that the new method achieves a totally high accuracy of TIS prediction. Compared with existing TIS predictors, the method reports a totally higher performance, especially for genomes that are GC-rich or have complex initiation mechanisms. The potential application of the method to improve the TIS annotation deposited in the public database was also proposed.

STIM1 is recognized as an ER Ca2+ sensor of calcium release-activated calcium (CRAC) channel that is constructed by membrane protein Orai1, However, this regulatory system may also be regulated by other proteins. Reticulocalbin 2 (RCN2) was purified and identified from STIM1-Orai1 complex. Confocal microscopy revealed that RCN2 co-localized with STIM1 in ER before and after Ca2+ store depletion. Single cell [Ca2+]I measurements of RCN2 EF hands mutant showed slight influence on SOC electrophysiological characters. Furthermore, a novel collar form aggregation of RCN2 surrounding STIM1 clusters suggested that RCN2 potentially plays a role of structure maintenance in STIM1 clustering.

Many somatic cell typos were obtained by in vitro differentiation or teratoma formation of human embryonic stem ceLls (hESCs). However, it is unclear whether specific cell types can be obtained from hESCs-derived teratoma. It was reported that many kinds of cells, including neural progetfitor/precursor cells (NPCs) and mesenchymal stem cells (MSCs) were isolated efficiently from the teratoma of hESCs through in vitro selection. The teratoma-derived NPCs and MSCs showed specific characteristics of molecular markers similar to the primary NPCs and MSCs. Moreover, these teratoma-induced NPCs and MSCs can be further induced to differentiate into neurons, astrocytes, or adipose and bone cells, reflecting their inherent multi-potencies. Given that teratoma normally contains a mixture of ectoderm, mesodenn, and endoderm lineage cells at different differentiation stage, it was suggested that hESCs-derived teratoma could be an alternative source to generate a variety of uncommitted progenitor cells or terminally differentiated somatic cells, which may be otherwise difficult to obtain through direct in vitro differentiation.

Pancreatic acinar cells synthesize pancreatic lipase related protein 1 (PLRPl), which has a high degree of sequence and structural homology with pancreatic triglyceride lipase (PTL). PTL is required for efficient dietary triglyceride digestion, while the physiological role of PLRPl has not been elucidated, although some investigations have shown that its expression level is changed under some physiological or pathological conditions. Specific antigenic peptides were fused to glutathione S-transferase (GST) and purified recombinant fusion protein was used to generate polyclonal antisera by immunization of rabbits. The antisera could detect the antigen as low as 0.6 ng and PLRPI protein in 3 μg of mouse pancreatic juice extracts. The high specificity was verified in Western blot and immunohistochemistry analysis by using PLRPl knockout (KO) mice as the control. Furthermore, it was showed that food intake could increase the exocrine secretion of PLRPl into pancreatic juice. This implied that PLRPl may fulfill dietary digestion function in the digestion track.

SAαt2,6 and SAα2,3 linked sialic acid molecules on epithelial cell membrane served as receptors for influenza virus, which axe specifically recognized by human and avian influenza viruses, respectively. The distribution of these two species of sialic acids in human respiratory tract from different anatomical sites and different age groups was investigated. The results showed that SAα2,3Gal species was prevalent in respiratory bronchiole and lung alveolar epithelium, but was infiequent in trachea, bronchus and bronchiole. On the contrary, the SAα2,6Gal species was more common in the trachea and bronchus and to a lesser degree in the alveolar epithelium. When compared the expression levels of SAα2,6Gal and α2,3Gal in the respiratory tract among different age groups, no significant difference was found. In the ex vivo H5N1 virus infection study, alveolus epithelium were found to be more susceptible to avian influenza than trachea and bronchus epithelial cells. These results suggest that the human respiratory tract, to some extent, is permissive for avian influenza viruses. The currently-observed limited human to human transmission of H5N1 virus may be associated with the different abundance of SAα2,3Gal linkages in human upper respiratory tract among individuals.

Transient receptor potential A1 (TRPAl) is a cold sensitive cation channel, which could also be activated by various pungent compounds. As a transduction channel in a number of sensory modalities, TRPAl expressing in heterogonous systems serves to provide great convenience in pharmacological analysis and functional investigation. Due to cellular toxicity, establishment of stable TRPAl cell line has always been challenging. Nevertheless, the first stable human embryonic kidney (HEK-293) cell line with un-controlled expression of TRPAl was successfully established. It was also confirmed that this stable cell line retained TRPAl expression for more than 25 passages in culture. The functional analysis of the cell response verified the stability and specificity of this novel recombinant TRPAl cell line. Altogether, the data indicated this TRPAl-HEK cell line would be a useful tool for functional analysis of TRPAl and for the development of high throughput screening (HTS) compatible assay in the effort to identify TRPAl modulators.

The molecular mechanism underlying muscular atrophy and gravisensing during spaceflight is still unknown. The major effects of spaceflight on body-wall muscles of Caenorhabditis elegans (C. elegans) in the structures and functions wore examined, and five important muscle-related genes and three proteins were studied after nearly 15-day spaceflight. The changes for the wall-muscles were observed in situ. Decreased muscle fiber size was observed with myosin immunofluorescence and duller dense-body staining in flight samples, which suggested that muscular atrophy had happened during spaceflight. However, F-actin staining showed no differences between the spaceflight group and ground control group. Otherwise, after returning to the earth the C eleganu displayed reduced rate of movement with a lower ratio (height/width) in crawl trace wave, which indicated a functional defect. These results demonstrated that C. elegans muscular development was changed in response to microgravity, and changes also occurred at the level of gene transcription and protein translation. Expression of dys-I increased significantly in body-wall muscles, while hlh-1, myo-3, uric-54 and eg1-19 RNA levels decreased after spaceflight. Dystrophin (encoded by dys-1) is one of important components in dystrophin-glycoprotein complex (DGC). Increased dys-I expression after flight implied that the muscular cell would accept more gravity signals by DGC in mierogravity in order to keep mechanical balance within the cells. It is concluded that DGC was involved into the mechanical transduction in body-wall muscles of C. elegans when gravity varied, which potentially played a vital role in gravisensing. The changes ofhlh-l, myo-3, tmc-54 and egl-19 suggested that they had the effects of promoting microgravity-induced muscular atrophy in strcture and function aspects. Result of Western blotting showed that the level of myosin A in spaceflight group decreased, further confirmed that atrophy happened during flight.

Metabolic characteristics of 39 human brain tumor tissues, including 15 astrocytomas, 13 fibroblastic meningiomas and 11 transitional meningiomas from 39 individual patients, have been studied using high resolution magic-angle spinning (HRMAS) 1H NMR spectroscopy in conjunction with principal component analysis (PCA). With rich metabolite information, 1H NMR spectra showed that the tumor-tissuc metabonome was dominated by lipids, lactate, myo-inositol, ereatine, choline metabolites such as choline, phosphocholine and glycerophosphocholine, amino acids such as alanine, glutamate, glutamine, taurine, N-acetyl-aspartate and glutathione. PCA of the tumor NMR spectra clearly showed metabonomic differences between low-grade astrocytomas and meningiomas whereas such differences were more moderate between fibroblastic and transitional meningiomas. Compared with meningiomas, the low-grade astrocytomas had higher levels of glycerophosphocholine, phosphocholine, myo-inositol and creatine but lower levels of alanine, glutamate, glutamine, glutathione and taurine. The N-acetyl-aspartate level was low but detectable in low-grade astrocytomas whereas it was not detectable in meningiomas. It is concluded that tissue metabonomics technology consisting of HRMAS 1H NMR spectroscopy and multivariate data analysis (MVDA) offers a useful tool (1) for distinguishing different types of brain tumors, (2) for providing the metabolic information for human brain tumors, which are potentially useful for understanding biochemistry of tumor progression.