Science in China. Series C, Life Sciences / Chinese Academy of Sciences最新文献

Human ADAM19 is a recently identified member of the ADAM family. It is highly expressed in human placentas, but its dynamic change and function at the human feto-maternal interface during placentation remain to be elucidated. In this present study, the spatial and temporal expression and cellular localization of ADAM19 in normal human placentas were first demonstrated, and the effects of ADAM19 on trophoblast cell adhesion and invasion were further investigated by using a human choriocarcinoma cell line (JEG-3) as an in vitro model. The data demonstrated that ADAM19 was widely distributed in villous cytotrophoblast cells, syncytiotrophoblast cells, column trophoblasts, and villous capillary endothelial cells during early pregnancy. The mRNA and protein level of ADAM19 in placentas was high at gestational weeks 8-9, but diminished significantly at mid- and term pregnancy. In JEG-3 cells, the overexpression of ADAM19 led to diminished cell invasion, as well as increases in cell adhesiveness and the expression of E-cadherin, with no changes in beta-catenin expression observed. These data indicate that ADAM19 may participate in the coordinated regulation of human trophoblast cell behaviors during the process of placentation.

Previous studies of young people have revealed that the left dorsolateral prefrontal cortex (DLPFC) plays an important role in inductive reasoning. An fMRI experiment was performed in this study to examine whether the left DLPFC was involved in inductive reasoning of MCI patients and normal aging, and whether the activation pattern of this region was different between MCI patients and normal aging. The fMRI results indicated that MCI patients had no difference from normal aging in behavior performance (reaction time and accuracy) and the activation pattern of DLPFC. However, the BOLD response of the DLPFC region for MCI patients was weaker than that for normal aging, and the functional connectivity between the bilateral DLPFC regions for MCI patients was significantly higher than for normal aging. Taken together, these results indicated that DLPFC plays an important role in inductive reasoning of aging, and the functional abnormity of DLPFC may be an earlier marker of MCI before structural alterations.

Because plants are sessile organisms, the ability to adapt to a wide range of environmental conditions is critical for their survival. As a consequence, plants use hormones to regulate growth, mitigate biotic and abiotic stresses, and to communicate with other organisms. Many plant hormones function pleiotropically in vivo, and often work in tandem with other hormones that are chemically distinct. A newly-defined class of plant hormones, the strigolactones, cooperate with auxins and cytokinins to control shoot branching and the outgrowth of lateral buds. Strigolactones were originally identified as compounds that stimulated the germination of parasitic plant seeds, and were also demonstrated to induce hyphal branching in arbuscular mycorrhizal (AM) fungi. AM fungi form symbioses with higher plant roots and mainly facilitate the absorption of phosphate from the soil. Conforming to the classical definition of a plant hormone, strigolactones are produced in the roots and translocated to the shoots where they inhibit shoot outgrowth and branching. The biosynthesis of this class of compounds is regulated by soil nutrient availability, i.e. the plant will increase its production of strigolactones when the soil phosphate concentration is limited, and decrease production when phosphates are in ample supply. Strigolactones that affect plant shoot branching, AM fungal hyphal branching, and seed germination in parasitic plants facilitate chemical synthesis of similar compounds to control these and other biological processes by exogenous application.

To obtain high titer monoclonal antibodies (McAbs) which can react with mammalian prion protein (PrP), Balb/C mice were immunized with bovine (Bo) PrP peptide (BoPrP 209-228 aa) coupled to keyhole limpet hemocyanin (KLH). The hybridoma cell lines secreting monoclonal antibodies against the peptide were established by cell fusion and cloning. The obtained McAbs were applied to detect recombinant human, bovine and hamster PrP, cellular prion protein (PrP(c)) in normal bovine brain and pathogenic scrapie prion protein (PrP(Sc)) accumulated in the medulla oblongata of bovine spongiform encephalopathy(BSE)specimen with Western blot and immunohistochemical detection, respectively. The current procedure might offer a simple, feasible method to raise high titer antibodies for studying biological features of PrP in mammals, as well as detection of transmissible spongiform encephalopathy (TSE) and diagnosis of BSE, in particular.

The present study was designed to investigate possible relationships between the genotypes of hepatitis B virus (HBV) and the HBV-specific cytotoxic T lymphocyte (CTL) responses. HBV genotypes, HBV specific CTL HBV DNA and other markers of HBV infection were determined in 138 patients with chronic hepatitis B. The results showed that the patients infected with genotype C (n=62) had a significantly lower HBV-specific CTL response than those who were infected with HBV genotype B (P<0.01). HBV DNA titer was higher in patients infected with HBV genotype C than in those infected with HBV genotype B (P<0.01). Both alanine aminotransferase (ALT) and total bilirubin (TBIL) were higher in HBV genotype C infected patients than in those infected with genotype B (P<0.01 and <0.05, respectively). These results suggest that compared with CHB patients infected with HBV genotype B, the higher HBV DNA level and more severe liver damages in the patients infected with genotype C of HBV may be associated with genotype C of the virus.

Plants possess some desirable characteristics to synthesize recombinant glycoproteins for pharmaceutical application. However, the mammalian glycoproteins produced in plants are somewhat different from their natural counterparts in terms of N-glycoforms. The immunogenicity of plant-specific glyco-epitopes is the major concern in human therapy. Here, the distribution of N-glycans in different growth phases of tobacco BY2 cells and their immunogenicity in mice were determined. It was observed that the percentage of beta1,2-xylose and alpha1,3-fucose in proteins of growing cells increased and the corresponding protein extracts caused accelerated immune response in mice. Based on this observation, the recombinant erythropoietin in BY2 cells was expressed and characterized, and Western blot analysis showed that the recombinant erythropoietin contained a relatively small amount of plant-specific glyco-epitopes in the early phase of culture growth. This study may provide a simple but effective strategy for the production of therapeutic glycoproteins with human-like N-glycan structures in plant hosts to avoid a great allergenic risk.

In the management of lake eutrophication, the regulation effect of Fe is considered, in addition to the controlling nitrogen- and phosphorus input. Based on the "Fe hypothesis", this paper tentatively applied plant spectral response to the remote sensing early-warning mechanism of lake eutrophication. A laboratory water culture experiment with rice (Oryza sativa L.) was conducted to study Fe uptake by plants and the chlorophyll concentration and visible-near infrared spectrum of vegetable leaves as well as their interrelations under Fe(2+) stress. Three spectral indices, i.e., A (1) (integral value of the changes of spectral reflectivity in the range 460-670 nm under Fe(2+) stress), A (2) (integral value of the changes of spectral reflectivity in the range of 760-1000 nm under Fe(2+) stress) and S (blue-shift range of red edge curve under Fe(2+) stress), were used to establish quantitative models about the relationships between the rice leaf spectrum and Fe(2+) stress. With the increase of Fe(2+) in a culture solution, the Fe content in rice plants increased, while the chlorophyll concentration in vegetative leaves decreased. The spectral reflectivity of vegetable leaves increased in the visible light band but decreased in the near infrared band, and the blue-shift range of the red edge curve increased. The indices A (1), A (2) and S all had significant correlations with the Fe content in rice leaves, the correlation coefficient being respectively 0.951 (P < 0.01), -0.988 (P < 0.01) and 0.851 (P < 0.01), and simulated (multiple correlation coefficients R (2) > 0.96) and predict the Fe level in rice leaves.

The Autographa californica nucleopolyhedrovirus (AcMNPV) contains three apoptosis suppressor genes: p35, iap1 and iap2. AcMNPV P35 functions as a pancaspase inhibitor, but the function of IAP1 and IAP2 has not been entirely resolved. In this paper, we analyze the function of IAP1 and IAP2 in detail. AcMNPV with p35-deletion inhibited the apoptosis of BTI-Tn-5B1-4 (Tn-Hi5) cells induced by a Helicoverpa armigera single nucleocapsid NPV (HearNPV) infection and rescued the replication of HearNPV and BV production in these cells. Transient-expression experiments indicated that both IAP1 and IAP2 suppress apoptosis of Tn-Hi5 cells during HearNPV infection. Recombinant HearNPVs expressing AcMNPV iap1, iap2 and p35, respectively, not only prevented apoptosis but also allowed HearNPV to replicate in Tn-Hi5 cells. However, the iap1, iap2 and p35 genes when expressed in HearNPV were unable to rescue BV production. These results indicate that both AcMNPV iap1 and iap2 function independently as apoptosis inhibitors of and are potential host range factors.

Inhibitory control dysfunction is regarded as a core feature in addicts. The major objective of this study was to explore the time course of response inhibition in chronic heroin addicts and provide the neurophysiological evidence of their inhibitory control dysfunction. The amplitudes and latencies of ERP components were studied in fourteen heroin addicts (mean duration of heroin use being (13.54+/-5.71) years (Mean+/-SD), average abstinence being ((4.67+/-6.44) months)) and fourteen matched healthy controls with a visual Go/Nogo task. Our results showed that heroin addicts demonstrated significantly larger Go-N2 amplitudes which results in a decreased N2 Go/Nogo effect, but no statistically significant differences were found between heroin addicts and controls in P3. The ERP data suggest that fronto-central areas of heroin addicts were impaired during the inhibition process (200-300 ms) and over-activated to targets. The impaired early process might reflect an abnormal conflict monitoring process in heroin addicts. These results consolidate the inhibitory control dysfunction hypothesis in chronic heroin users.

Although prefrontal and hippocampal neurons are critical for spatial working memory, the function of glial cells in spatial working memory remains uncertain. In this study we investigated the function of glial cells in rats' working memory. The glial cells of rat brain were inhibited by intracerebroventricular (icv) injection of fluorocitrate (FC). The effects of FC on the glial cells were examined by using electroencephalogram (EEG) recordings and delayed spatial alternation tasks. After icv injection of 10 microL of 0.5 nmol/L or 5 nmol/L FC, the EEG power spectrum recorded from the hippocampus increased, but the power spectrum for the prefrontal cortex did not change, and working memory was unaffected. Following an icv injection of 10 microL of 20 nmol/L FC, the EEG power spectra in both the prefrontal cortex and the hippocampus increased, and working memory improved. The icv injection of 10 microL of 50 nmol/L FC, the EEG power spectra in both the prefrontal cortex and in the hippocampus decreased, and working memory was impaired. These results suggest that spatial working memory is affected by centrally administered FC, but only if there are changes in the EEG power spectrum in the prefrontal cortex. Presumably, the prefrontal glial cells relate to the working memory.