Abstract:Although the structure of hippocampus in the brain of mammals has been discovered for several centuries, the function was identified just several decades ago. Now the hippocampus has become a key model for studying the cellular and molecular bases of cognition such as learning and memory. Here the relevant papers which were published in Progress in Biochemistry and Biophysics in recent years are reviewed.

Abstract:Sixty years has passed since the inaugural Science in China was published in 1950, and at the same time The Chinese Academy of Sciences was founded. Science in China, which is used to be the most important journal reporting Chinese science and technology achievements, is committed to publishing high-quality, original research results in both basic and applied researches. The advisory board of Science in China has been restructured and the editorial board has been renewed in 2008. Science in China sponsored by The Chinese Academy of Sciences and Progress in Natural Science sponsored by the National Natural Science Foundation of China were merged in 2009 and the journal is renamed Science China.
The year 2009 marked a new beginning for Science China: Life Sciences. It has a dramatic improvement in many aspects: a newly formed international editorial board, individualized color cover for each issue, articles contributed by international authors, and so on. Throughout the year 2009, six issues of the journal published articles focusing on a special topic, covering: the genomics; microRNA ; epigenetics; avian influenza virus; stem cells . In adition, total of about 200 academic articles have been published. This review will make a retrospect of Science China : Life Sciences in 2009.

Abstract:Pseudogenes, disabled copies of functional genes, are structurally similar to its parantal genes, but lost their ability to produce proteins. Pseudogene was used to be considered as a typical kind of non-coding “junk DNA”. Increasing investigations, however, have shown that pseudogenes play important roles in gene regulation and genome evolution. The progress of research on pseudogenes is summarized in light of the origin and sequence characteristics of pseudogenes, identification of pseudogenes, genomic distribution, behaviour of its molecular evolution and functioning.

Abstract:Calcium (Ca²⁺)-activated chloride channels play fundamental roles in numerous physiological processes including transepithelial ion/fluid secretion, cardiac and neuronal excitation, sensory transduction, smooth muscle contraction and fertilization, etc. Despite their physiological importance，the molecular identity of CaCC has not fully invested till now. Here the newly discovered CaCCs molecular basis TMEM16A was reviewed in the respects of the identification processes, gene structure and functions, ion channel's electrophysiological characters, related diseases, pharmocoligical functions and other current hot issues in the fields. The developmental trends of this field were discussed.

Abstract:The LASP-1 gene was initially identified from a cDNA library of metastatic axillary lymph nodes (MLN) from human breast cancer. The Lasp-1 gene encoded a putative protein containing a LIM motif at its amino terminus and a src homology 3 (SH3) domain at its C-terminal part. Overexpression of LASP-1 has been reported in many kinds of malignant tumors, such as breast cancer and ovarian cancer. LASP-1 is closely related to genesis, invasion and metastasis of tumor. Recently, LASP-1 was identified as a novel transcriptional target of tumor suppressor gene p53. On the basis of the existing data, LASP-1 is a novel tumor suppressor protein.

Abstract:As understanding of neural mechanisms gets deeper, application of neuroimaging improves as well, including its technologies, methods, and various tools. The improvement includes continuous progress in the neuroimaging technology itself and synchronized recording of neuroimaging with direct stimulation on the brain. Synchronization of TMS and fMRI, TMS and EEG technologies are being well established and provided technical support for exploring functional and effective connectivity of human brain network. These technologies suggest new ways of the brain study in the fields of neuroscience, cognitive psychology, and neural informatics. Furthermore, they can help to understand the working mechanisms of the human brain.

Abstract:Though the hypothesis of "aspecific amyloid ion channels" has been proposed by Lin, et al (University of California, Santa Barbara) to explain the mechanism of metabolic dysfunction and cell death during protein conformational diseases, the "pore-like" aggregates of misfolded neural Tau have not been observed. Revulsants involved in the formation of "pore-like" aggregates have not been found yet. According to the hypothesis "chronic impairment resulted from abnormally-increased endogenous formaldehyde is one of the important risk factors related to sporadic senile dementia", formaldehyde has been utilized to incubate with Tau protein resulting in amyloid-like deposits with marked cytotoxicity. Under the experimental conditions, 0.5% formaldehyde-treated Tau could form "pore-like" aggregates. These results may deliver a novel approach to study the mechanism of cellular metabolic disturbance, even cell death, which is induced by formaldehyde-treated neural Tau.

Abstract:Chronic obstructive pulmonary disease (COPD) development is the result of environmental factors interact with hereditary factors, and smoking is the primary cause for COPD development. Nevertheless, both the mechanisms of smoking leads to COPD and the mechanisms of COPD hereditary susceptibility are not well clarified so far. Proteomics research features high efficiency and rich information, which had provided strong help for COPD study, and considered has broad prospects in COPD research area. Two dimensional gel electrophoresis and matrix assisted laser desorption/ionization time of flight mass spectrometry were used in proteomics research to compare the lung tissue proteome of never-smokers, non-COPD smokers and COPD smokers. By combined with bioinformatics technology, 24 proteins were identified to be differentially expressioned between groups. The D4-GDI expression level in lung tissue of non-COPD smokers was 1.7 times to never-smokers, while the D4-GDI expression level in lung tissue of COPD smokers was nearly twice to non-COPD smokers. For verification, D4-GDI expression level in lung tissue was detected by immunohistochemical staining and Western-blotting, and the results was consistent with proteomics research. The results of this study for the first time to description: Smoking can up-regulate D4-GDI expression level in lung tissue, D4-GDI involved in the pathogenesis of COPD and may be associated with COPD susceptibility.

Abstract:The synthesis of optically active (R)-ketone-cyanohydrin catalyzed by (R)-oxynitrilase from Prunus salicina seed meal via enantioselective transcyanation of acetyltrimethylsilane with acetone cyanohydrin in the water/organic solvent biphasic system was studied by GC analysis on a chiral β-Cyclodextrin Column. The effects of different (R)-oxynitrilase sources, diameter size of crude enzyme, substrate concentration, the ratio of two substrates, enzyme concentration and substrate structure on the enzymatic enantioselective transcyanation were investigated systematically. The results showed that (R)-oxynitrilase from Prunus salicina could efficiently catalyze enantioselective transcyanation of acetyltrimethylsilane with acetone cyanohydrin. The optimal diameter size of crude enzyme, concentration of acetyltrimethylsilane, ratio of acetone cyanohydrin to acetyltrimethylsilane and crude enzyme concentration were 0.3～0.45 mm, 21 mmol/L, 2∶1 and 60.9 g/L, respectively. (R)-oxynitrilase from Prunus salicina could not accept 3, 3-dimethyl-2-butanone as substrate, while both high substrate conversion and high product ee% were obtained with its silicon counterpart acetyltrimethylsilane as the substrate. Under the optimal conditions, both acetyltrimethylsilane conversion and enantiomeric excess of the product were above 99%. These results demonstrated that the silicon atom in substrate served as a more effective atom than the carbon atom to enhance the activity of this enzyme.

Abstract:Xenopus tropicalis is an important model animal in immunology. Based on the available genome data, the genomic organization of all three light chain gene (ρ, σ and typeⅢ) loci were recently characterized in Xenopus tropicalis. On the basis of similarity of protein sequences, genomic organization and chromosomal location of the light chain genes among frogs and mammals, the data strongly support the previous suggestions that the ρ genes belong to the κ gene lineage, whereas the typeⅢ genes share a common origin with the λ genes. About 200 cDNA fragments from each of ρ, σ and typeⅢ genes, were cloned and sequenced respectively generating 22, 25 and 44 clones that have unique VJ junctions (after removal of redundant clones). Recombined VJ junctions of cloned light chain cDNA were analyzed, which showed a paucity of N and P nucleotides in expressed ρ, σ and typeⅢ genes. They also show that somatic VJ rearrangements of the σ gene seemed to be dependent on short stretches of homologous nucleotides (microhomology). The microhomology-directed VJ recombination obviously results in very limited diversity. However, most expressed ρ and typeⅢ VJ junctions showed direct ligation or deletions of V and J coding ends. These results help researchers to understand the generation of Ig diversity in X. tropicalis.

Abstract:It was previously demonstrated that an intein-catalyzed splicing of B-domain deleted coagulation factor Ⅷ (BDD-FⅧ) heavy and light chains could improve the secretion of heavy chain in cis and the splicing can occur independently of cellular entities exhibiting a splicing activity in and out of the cell. In order to improve the efficacy of intein-based dual-vector delivery of the BDD-FⅧ gene, here an additional acidic region-3 (AR-3) between Pro¹⁶⁴⁰ and Ser¹⁶⁹⁰ of FⅧ proven to be helpful for the secretion of heavy chain was incorporated into BDD-FⅧ heavy chain to examine its effect on secretion and bioactivity of an intein-spliced BDD-FⅧ protein. By co-transfection of the cultured HEK293 cells with genes of the ar-3 incorporated heavy chain and light chain with fused intein (HCAR3IntN and IntCLC), an ELISA and Coatest assay were performed to determine the amount of spliced BDD-FⅧ protein and coagulation activity secreted in the culture supernatant, and the intracellular BDD-FⅧ splicing was observed by Western blotting. The data showed that the amount of spliced BDD-FⅧ protein (173±26) μg/L and coagulation activity (1.31±0.15) U/ml of supernatant from gene co-transfected cells were greater than supernatant from intein-fused ar-3-free heavy and light chain genes (HCIntN and IntCLC) co-transfected cells (102 ± 12) μg/L and (0.79 ± 0.09) U/ml indicating the additional AR-3 in the heavy chain could dramatically improve the secretion and activity of intein spliced BDD-FⅧ. A spliced BDD-FⅧ protein ((35±7) μg/L) and coagulation activity ((0.28±0.08) U/ml) was also detected in the culture supernatant of combined cells separately transfected with the HCAR3IntN and IntCLC genes implying the cellular entities independent BDD-FⅧ splicing of the intein. The total protein from gene co-transfected cells displayed an obvious protein band of the spliced BDD-FⅧ detected by a FⅧ polyclone antibody indicating the intracellular BDD-FⅧ splicing. It paved a way for ongoing study on protein trans-splicing based dual-adeno-associated virus (AAV) delivery of the split BDD-FⅧ gene in gene therapy for hemophilia A animals.

Abstract:Organophosphates are some the widely used pesticides in the world, their mechanism of acute toxicity is associated with inhibiting acetylcholinesterase (AChE). Recently, increasing attention has been put to paraoxonase (PON1) which hydrolyzes OPs and prevents atherosclerosis by its anti-oxidation effects on low density lipoproteins (LDLs), resulted in decreased pro-inflammatory lipid peroxides formation. Since vascular endothelial dysfunction is known as the primary step in atherogenesis, the influence of OPs on the vascular endothelial function was assessed. Results showed that trichlorfon (18 mg·kg^-1) intragastrically daily for 70 days in rabbits resulted in a significant inhibition of endothelium-dependent relaxation (EDR), a decrease of endothelium nitric oxide synthase (eNOS) activity in isolated aorta and the changes of biochemical parameters in plasma, including a decrease of superoxide dismutase (SOD), PON1 and AChE activity and nitric oxide level and an increase of malondialdehyde (MDA) level. In addition, a direct exposure of rabbit aortic rings to paraoxon also inhibited EDR. These findings suggest that subchronic toxicity dose intragastrically trichlorfon or vessels to be exposed directly to paraoxon in vitro could induce dysfunction of vascular endothelium. The mechanisms may involve an inhibition of antioxidases and oxidative stress induced by OPs.

Abstract:Understanding the initiation site and propagation of epileptiform discharges are of important significance for investigating the mechanisms of epilepsy and thereby for the clinically remedy. In order to solve the above problems, epileptiform discharges induced by low-Mg2+ artificial cerebrospinal fluid (ACSF) in Sprague- Dawley (SD) rat hippocampal slices were recorded by microelectrode array. Two components of epileptiform discharges: field potentials and multiple unit activity (MUA) were analyzed. Firstly, the onset time of field potentials in stratum pyramidale was calculated and compared to locate the initiation site and propagation of epileptiform discharges. Then cross-correlation analysis was applied to spike trains of MUA. Time delays obtained from cross-correlation function further confirmed the initiation site and propagation of epileptiform discharges in the whole hippocampal slice. The results revealed that epileptiform discharges in CA3 had larger amplitudes and longer duration than that in CA1, which indicated more excitability in CA3. Field potentials as well as MUA in CA3b occurred earlier compared with the synchronous signals in CA3c and CA1. The time delays between the onset and its following areas were positive relative to the distances between them. The result demonstrated that in low-Mg²⁺ ACSF-perfused SD rat hippocampal slice, epileptiform discharges originated from CA3b and propagated to CA3c and CA1 region respectively.

Abstract:To prepare citrinin(CIT)-protein antigen, CIT was conjugated with bovine serum albumin (BSA) by 1, 4-butanediol diglycidyl ether. The spleen from the BALB/C mice immunized with CIT-BSA conjugate was used to fuse with the murine SP2/0. By subcloning, a hybridoma cell lines excreting monoclonal antibodies(McAb) against CIT was obtained and named H2-F8. The monoclonal antibodies obtained from hybridoma H2-F8 was of IgM subclass. The affinity constant of the McAb to CIT was 4.17×10⁸ L/mol and the IC₅₀ value was 0.3 μg/L. Its linear range of the assay was between 0.05 μg/L and 1.0 μg/L. The cross-reactivity rates were less than 0.1% of other toxins such as ochratoxin A, aflatoxin B1, deoxynivalenol, zearalenone and were less than 0.01% of rubropunctatine and rubropunctamine. This work would be helpful for establishing the technology and developing the kit to determine CIT-contaminated samples by ELISA.