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Combining Goldenveizer-Novozhilov shell theory, thin plate theory and electro-elastic surface theory, the size-dependent vibration of nano-sized piezoelectric double-shell structures under simply supported boundary condition is presented, and the surface energy effect on the natural frequencies is discussed. The displacement components of the cylindrical nano-shells and annular nano-plates are expanded as the superposition of standard Fourier series based on Hamilton's principle. The total stresses with consideration of surface energy effect are derived, and the total energy function is obtained by using Rayleigh-Ritz energy method. The free vibration equation is solved, and the natural frequency is analyzed. In numerical examples, it is found that the surface elastic constant, piezoelectric constant and surface residual stress show different effects on the natural frequencies. The effect of surface piezoelectric constant is the maximum. The effect of dimensions of the double-shell under different surface material properties is also examined.

Background This study is to investigate the effect of fenofibrate on the bone quality of Type 2 diabetes mellitus (T2DM) mouse model. Methods T2DM mouse model was induced by high-fat-diet, and the mice were treated with fenofibrate (100 mg/kg) (DIO-FENO) or PBS (DIO-PBS) for 4 weeks. The bone microstructure and biomechanical properties of femora were analyzed by micro-CT and 3-Point bending test. The protein expression was detected by immunohistochemical staining and Western blot. The cell apoptosis was evaluated by TUNEL staining. The Bcl2, caspase 3, and osteoblast marker genes were detected by RT-qPCR. Results The biomechanical properties of bones from DIO-FENO group were significantly lower than those in the control and DIO-PBS groups. Besides, the trabecular number was lower than those of the other groups, though the cortical porosity was decreased compared with that of DIO-PBS group because of the increase of apoptotic cells. The expression of osteocalcin and collagen I were decreased after treatment with fenofibrate in T2DM mice. Moreover, the cell viability was decreased after treated with different concentrations of fenofibrate, and the expression of Runx2 decreased after treated with high dose of fenofibrate. Conclusion Fenofibrate decreases the bone quality of T2DM mice through decreasing the expression of collagen I and osteocalcin, which may be resulted from the down regulation of Runx2 expression.

The propagation behavior of Love wave in 0.67Pb(Mg1/3Nb2/3)O–0.33PbTiO3 (PMN–0.33PT) single crystal layered structure with the inhomogeneous initial stress varying along thickness is studied in this paper. The interface between PMN–PT layer and elastic substrate is perfectly bonded. The surface of the layered system is free of traction and electrically shorted or open. PMN–0.33PT single crystal is considered [011]c polarized, and has macroscopic symmetry of orthogonal mm2. The Frobenius method is employed to solve governing equation with variable coefficient. The analytical dispersion equations are derived for different boundary conditions. The numerical results show that the Frobenius method can provide a good asymptotic approximation when the retained number of items in Frobenius series is sufficient. It is found that the inhomogeneous initial stress has strong effect on the dispersion characteristics comparing with constant initial stress, whereas has less effect on the cut-off frequency for the first two modes of Love wave. The gradient coefficients of inhomogeneous initial stress can obviously affect the phase velocity and corresponding electromechanical coupling factor, and can also change the distributions of mechanical displacement, electrical potential and stress. The obtained results can provide a predictable and theoretical basis for design and manufacture of high performance surface acoustic wave devices.

In this paper, the multiple scattering of anti-plane shear waves around a coated nanowire with surfaces/interfaces embedded in a half solid is studied, and the dynamic stress at the two surfaces/interfaces is presented. The boundary condition at the edge of the half solid is satisfied by the image method. The analytical solutions of displacements in the two half solids, in the coating layers, and inside the nanowire are expressed by wave function expansion method. The expanded mode coefficients are determined by satisfying the boundary conditions at the two surfaces/interfaces of the coated nanowire and the straight edge of the structure. The addition theorem for cylindrical wave function is employed to accomplish the superposition of displacement fields in the two half solids. Analyses show that the properties of the outer and inner interfaces show different effect on the dynamic stress around the nanowire. The dynamic stress distribution around the nanowire is also significantly related to the interfacial properties at the edge and the position of the nanowire.

Based on a surface/interface continuum theory, a theoretical study of predicting the effective dynamics properties of nanocomposites with elliptical nano-fibers is presented. The extended version of effective medium method and coherent interface model are introduced to simplify the composites with randomly distributed elliptical nano-fibers. The conformal mapping method is applied to solve the problem of typical elliptical nano-fiber. The effective elastic modulus of nanocomposites is obtained on the basis of the derived imperfect interface conditions. High accuracy of the method is demonstrated by comparing with the solutions of cylindrical nano-fibers. The effects of the shape of the nano-fibers, the material properties of interface, and the wave frequency on the dynamic shear modulus are analyzed. It is found that the interface effect is significantly related to the shape of elliptical nano-fibers. The interacting effects of the shape and the incident direction of stress waves are also examined.

The use of electromagnetic relief valve with high pressure and large flow rate in hydraulic system is usually easy to bring vibration and noise issues, especially while water or high water based fluid (HWBF) is used as the fluid medium. In this paper, a HWBF electromagnetic relief valve with a cushion valve was presented and its simulation model was built based on AMESim software. Through simulation, it is found that the cushion valve can significantly reduce the peak pressure gradient of the electromagnetic relief valve during unloading process compared with that without a cushion valve. This research provides a new solution for solving the vibration and noise issues of a hydraulic system with electromagnetic relief valve.

Safety valves play very important role in protecting the safety of hydraulic support in coal mine. However, its development is greatly limited by the corresponding test bench for the dynamic experiment. In this paper, an experimental system for testing the dynamic performance of the safety valve with rated pressure up to 50MPa and rated flow rate up to 2000L/min, is introduced. Based on AMEsim software, modeling and simulation on the designed system is carried out. Some parameters of the system are also analyzed and their influences to the tested valve’s dynamic performance are obtained by simulation. It is found that the designed system, which adopting the combination of a piston and a plunger cylindersas well as accumulators, can fulfill the demands of the relevant standard. Among all the investigated factors, both the volume and pre-charged gas pressure of the accumulators have optimum values matching with the other parameters of the system. The stroke of the plunger cylinder, the rated flow rates of the cartridge valve and its pilot control valve, are required to be higher than a certain value to avoid negative effects on the dynamic performance of the tested valve. The research presented in this paper is helpful to the design of the test system.

FTSZ and MIN proteins play important roles in plastid division. Having previously identified FTSZ genes in Chlamydomonas reinhardtii, we have now isolated the nucleus-encoded MIND and MINE1 genes from this species. Sequence analyses showed that MIND is highly conserved, while MINE1 is less well conserved. Both proteins were localized to chloroplasts, probably due to their N-terminal transit peptides. The transcription levels of FTSZ and MIN genes in synchronous cultures of C. reinhardtii, in which the chloroplasts divided synchronously with their host cells, were examined. Semi-quantitative reverse transcription PCR (RT-PCR) analyses showed that mRNA abundance displayed a circadian pattern under light-dark cycles and continuous light and dark conditions. Maximal mRNA levels correlated with cell division, and thus, chloroplast division. This work indicates that plastid division is regulated by the circadian expression of FTSZ and MIN genes.

Microarray analysis is used to identify transcriptional targets. However, the direct targets of transcription factors cannot be distinguished from indirect ones; further, genes with low-expression levels cannot be identified by this method. In the present study, we exploit the cis -element dehydration-responsive element (DRE) that is known to be responsible for the transcription of DRE binding factor 1 (DREB1) targets in the promoter region of all Arabidopsis genes. Putative targets whose promoters contain the elements were verified by both microarray and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Five new DREB1/CBF direct targets were identified. Compared with traditional microarray analysis, our method is convenient and cost-effective for identifying the downstream targets of transcription factors.

Physcomitrella patens is well known because of its importance in the study of plant systematics and evolution. The tolerance of P. patens for high-salinity environments also makes it an ideal candidate for studying the molecular mechanisms by which plants respond to salinity stresses. We measured changes in the proteome of P. patens gametophores that were exposed to high-salinity (250, 300, and 350 mM NaCl) using two-dimensional gel electrophoresis (2-DE) via liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sixty-five protein spots were significantly altered by exposure to the high-salinity environment. Among them, 16 protein spots were down-regulated and 49 protein spots were up-regulated. These proteins were associated with a variety of functions, including energy and material metabolism, protein synthesis and degradation, cell defense, cell growth/division, transport, signal transduction, and transposons. Specifically, the up-regulated proteins were primarily involved in defense, protein folding, and ionic homeostasis. In summary, we outline several novel insights into the response of P. patens to high-salinity; (1) HSP70 is likely to play a significant role in protecting proteins from denaturation and degradation during salinity stress, (2) signaling proteins, such as 14-3-3 and phototropin, may work cooperatively to regulate plasma membrane H(+)-ATPase and maintain ion homeostasis, (3) an increase in photosynthetic activity may contribute to salinity tolerance, and (4) ROS scavengers were up-regulated suggesting that the antioxidative system may play a crucial role in protecting cells from oxidative damage following exposure to salinity stress in P. patens.

MinD is a ubiquitous ATPase that plays a crucial role in selection of the division site in eubacteria, chloroplasts, and probably Archaea. In four green algae, Mesostigma viride, Nephroselmis olivacea, Chlorella vulgaris and Prototheca wickerhamii, MinD homologues are encoded in the plastid genome. However, in Arabidopsis, MinD is a nucleus-encoded, chloroplast-targeted protein involved in chloroplast division, which suggests that MinD has been transferred to the nucleus in higher land plants. Yet the lateral gene transfer (LGT) of MinD from plastid to nucleus during plastid evolution remains poorly understood. Here, we identified a nucleus-encoded MinD homologue from unicellular green alga Chlamydomonas reinhardtii, a basal species in the green plant lineage. Overexpression of CrMinD in wild type E. coli inhibited cell division and resulted in the filamentous cell formation, clearly demonstrated the conservation of the MinD protein during the evolution of photosynthetic eukaryotes. The transient expression of CrMinD-egfp confirmed the role of CrMinD protein in the regulation of plastid division. Searching all the published plastid genomic sequences of land plants, no MinD homologues were found, which suggests that the transfer of MinD from plastid to nucleus might have occurred before the evolution of land plants.

Oligonucleotide microarrays were used to study the differences of gene expressions in high (H) and low (L) metastatic ovarian cancer cell lines and in normal ovarian tissues (C). Bioinformatics was used to identify novel genes and their functions as well as chromosomal localizations. A total of 409 genes were differentially expressed between the high and low metastatic ovarian cancer cell lines. Of them, 271 genes were up regulated (Signal Log Ratio[SLR] ≥1), and 138 genes were down regulated (SLR≤-1). Except one gene whose location was unknown, all these genes were localized randomly on all the chromosomes, with a majority of them localized to Chromosomes 1, 6, 2, 17, 3, 5 and 11. Chromosome 1 contained, 43 of them (10.7%), the most for a single chromosome. A total of 264 genes (64.7%) were localized on the short arm of the chromosome (q). Functional classification showed that the 104 (25.4%) genes coding for enzymes and enzyme regulators made up the largest functional group, followed by signal transduction activity genes (43, 10.5%), nucleic acid binding activity genes (42, 10.3%), and proteins binding activity genes (34, 8.3%). These four groups accounted for 54.5% of all the differentially expressed genes. In addition, the functions of 76 genes (18.6%) were unknown. Tumor metastasis is the result of a number of genes acting in concert. The four functional groups of genes classified among these genes and their abnormalities would be the focus of further studies on ovarian cancer metastasis.

A new algorithm is developed to compute a smooth and accurate satellite orbit on the basis of a kinematic orbit and a force model. Such a smoothed orbit is needed e.g. in the gravity field modeling procedure that is based on satellite accelerations. The procedure makes use of residual satellite accelerations defined as the difference between the observed accelerations and the reference ones. Computation of the reference accelerations requires an accurately determined set of satellite positions, which can be taken over from the smoothed orbit. The algorithm for computing the smoothed orbit is based on B-splines. A component of the orbit (i.e. a set of X-, Y -, or Z- coordinates in an inertial frame) is parameterized as a linear combination of B-spline functions with corresponding coefficients. These coefficients are determined by means of a least-square adjustment scheme. A force model is exploited to compute satellite accelerations, which are used as additional constraints. In order to find the balance between errors in the positions and unaccuracies of the computed accelerations, the generalized cross-validation technique is implemented. Thanks to the property of a local support of B-splines, the procedure is very efficient numerically. A numerical example demonstrates a performance of the proposed procedure. Furthermore, it shows that the solution with acceleration constraints is better than the solution based on the kinematic orbit only. The more precise the force model is, the more accurate smoothed orbit is obtained. Finally, a set of real CHAMP data is considered in the context of gravity field modeling. Smoothed orbits, which are computed both with and without acceleration constraints, as well as the original kinematic orbit are employed for calculating reference accelerations. The “Delft approach” is applied to recover gravity field models, which are compared with the EIGEN-CG01C model. The results show that usage of the smoothed orbit obviously improves the gravity field model, especially if the smoothed orbit is computed with acceleration constraints.

The role of dislocation scattering in electron mobility in ZnMgO/ZnO heterostructures was studied. It was found that dislocation scattering was dominant in the low-electron concentration region. The total low-temperature mobility was calculated by considering dislocation scattering and interface-roughness scattering (IRS) together. The sheet density of dislocations was chosen as Ndis=1.5 × 108 cm-2 and the IRS parameters were Δ = 5.206 and Λ = 30 Å. We obtained a good fit between our calculated results and experimental data reported in the works referenced.

Interface between the constituents plays an important role in the non-destructive detection of smart piezoelectric/piezomagnetic devices. The propagation of SH waves in nano-sized cylindrically multiferroic composites consisting of a piezoelectric layer and a piezomagnetic central cylinder is investigated, and the size-dependent dispersion relation with interface effect is derived. The general solutions of decoupled governing equation in different regions are expressed by using Bessel functions, and the unknown coefficients are determined by satisfying the boundary conditions at the inner interface with negligible thickness and the outer surface of the structure. Through the numerical examples of dispersion relation, it is found that the interface around the nano-cylinder may remarkably reduce the phase velocity, depending on the combination of the value of thickness ratio and the surface condition. The interface shows different effect on the first and second modes of dispersion relation.

To isolate Fe-deficient related (Fdr) genes, an expression cDNA library of 4.5×105 pfu/μg has been constructed from maize roots in iron-stress. 6 clones have been screened from the cDNA library by differential hybridization screening. It is proved that anFdr3 cDNA clone expressed stronger under iron-deficient condition than under iron-sufficient one by Northern blot and Western blot.

We investigate the plasmon mode coupling and depolarization shifts in AlGaAs/GaAs asymmetric step quantum wells (ASQWs) of the two-subband model with the Bohm–Pine’s random-phase approximation with and without an applied electric field. By adjusting the well geometry parameters and material composition systematically, various characteristics of plasmons in ASQWs are found for different asymmetric cases. We find that (i) the intersubband plasmon has a large negative dispersion in long wavelength limit; (ii) the step width related depolarization shift depends on the number of subbands in the deep well; and (iii) the influence of electric field effect on depolarization shift and the coupling of the two plasmon modes is quite asymmetric with its minimum at +8 kV/cm by changing the electrical field and the ASQW structure parameters. The coupling and decoupling of the intersubband and intrasubband plasmon modes can be realized by adjusting the polarity and the strength of the external electric field and changing the ASQW structure parameters.

The explants cells of Nicotiana Tobacum undergo the process of dedifferentiation and redifferentiation under the treatment of phytohormone with different contentrations. By monitoring the change of plastids and the expression of FtsZ protein, which functions in the progress of chloroplast division, we show that chloroplasts turn into amyloid and hypostasis when explants dedifferent and at the same time the expression of FtsZ proteins decreases. When explants redifferent and bud, hypostasis turn back into the chloroplast and the expression of FtsZ protein restores. The concurrence of fluctuant expression of FtsZ protein and the progress of bud differentiation and formation of chloroplast play essential roles in the growth of green plant.

To investigate the relationship of the metastasis-associated genes and its copy numbers variation in the highly metastatic human epithelial ovarian cancer cell line HO-8910PM.The differentially expressed genes and its copy number variation between HO-8910PM cell line and normal ovarian tissues was detected by human genome U133A 2.0 gene chip and human mapping 10K array 2.0 gene chip, and the data was analyzed by bioinformatics. Some of metastasis-associated genes were validated the results of single nucleotide polymorphism (SNP) and cDNA chips by fluorescence in situ hybridization (FISH) and real-time quantitative PCR.Integrate analysis of two gene chips data showed that there were 385 differentially expressed genes in the same and 379 SNP positional point (6 of them, included 2 genes) between HO-8910PM cell line and normal ovarian tissues, these copy number amplification of 379 SNP positional point of chromosome wereor = 3, which had 240, deletionor = 1 had 139. Chromosome location analysis showed that there were 385 differentially expressed genes located at all chromosomes, and 261 of them (67.8%, 261/385) located at 10 chromosomes, included that 34 (8.8%), 33 (8.6%), 28 (7.3%), 27 (7.0%), 25 (6.5%), 24 (6.2%) of them located at chromosome 3, 2, 9, 10, 1 and 11 respectively, and 23 (6.0%) of them at chromosome 6 and 12 each, 22 (5.7%) of them at chromosome 4 and 5 each. For the function of differentially expressed genes, the results showed that 99 (25.7%) genes belonged to the family of enzymes and their regulators, 54 (14.0%) genes associated with signal transduction, 50 (13.0%) genes associated with nucleic acid binding, and 36 (9.4%) genes associated with protein binding.We have demonstrated that there are 4 kinds of differentially expressed genes related to metastasis of ovarian cancer, which belonged to the families enzyme and its regulator, nucleic acid binding, signal transduction and protein binding, and located at chromosome 1, 2, 3, 4, 5, 6, 9, 10, 11 and 12.

Chloroplasts are a vital group of organelles of plants, yet the molecular mechanisms associated with their division remain poorly understood. Recent studies have revealed that the FtsZ protein, known as a key component in prokaryotic cell division, is involved in chloroplast division process. The NtFtsZ2-1 gene was isolated from Nicotiana tabacum by RT-PCR, and the sense and antisense expression plasmids were used to examine the function of NtFtsZ2-1 gene in transgenic tobacco. Light and confocal observations revealed that the normal chloroplast division process was severely disrupted in transgenic plants with enhanced or reduced expression of NtFtsZ2-1 gene. These chloroplasts were abnormally larger in size and fewer in number compared with that of the wild-type tobacco. But the total chloroplast plan area per mesophyll cell was conserved in sense, antisense and wild type tobaccos. Analyses of electron micrographs and chlorophyll content of different transgenic plants showed that constitutively enhancing or inhibiting the expression of NtFtsZ2-1 gene had no direct influence on the ultrastructure and photosynthetic ability of chloroplasts. Basing on these results, we suggest that NtFtsZ2-1 gene is involved in chloroplast division and expansion; the fluctuation of NtFtsZ2-1 expression level would alter normal chloroplast number and size in plant cells. In addition, the similarities of ultrastructure and photosynthetic ability of chloroplasts among sense, antisense and wild type tobaccos implies that a special mechanism regulate the relationship between chloroplast number and size to maximize photosynthetic rate.

The dehydration-responsive element binding (DREB) transcription factors play central roles in regulating expression of stress-inducible genes under abiotic stresses. In the present work, PpDBF1 (Physcomitrella patens DRE-binding Factor1) containing a conserved AP2/ERF domain was isolated from the moss P. patens. Sequence comparison and phylogenetic analysis revealed that PpDBF1 belongs to the A-5 group of DREB transcription factor subfamily. The transcriptional activation activity and DNA-binding specificity of PpDBF1 were verified by yeast one-hybrid and electrophoretic mobility shift assay experiments, and its nuclear localization was demonstrated by particle biolisitics. PpDBF1 transcripts were accumulated under various abiotic stresses and phytohormones treatments in P. patens, and transgenic tobacco plants over-expressing PpDBF1 gained higher tolerance to salt, drought and cold stresses. These results suggest that PpDBF1 may play a role in P. patens as a DREB transcription factor, implying that similar regulating systems are conserved in moss and higher plants.

To screen the carcinogenesis associated genes in gastric carcinoma by gene chip.U133A (Affymetrix Santa Clara, CA) gene chip was used to detect differentially expressed genes in tumor tissues, paratumor mucosa and normal mucosa. Bioinformatics was used to analyze the screened results.A total of 150 genes were detected with a difference of expression levels more than 3 times in paratumor mucosa compared with normal gastric mucosa, 130 of which were up-regulated and 20 down-regulated. According to the function classifications of the differentially expressed genes, the most common ones were enzyme and enzyme regulon activity associated genes(28, 18.7% ). The frequencies of nuclei acid binding activity associated genes,signal transduction associated genes and protein binding associated genes were 11.3%, 10%, and 8.7% respectively. Seventy-one differentially expressed genes were detected both in tumor tissues and paratumor mucosa compared with normal mucosa, 61 of which were up-regulated and 10 down-regulated. Among these 71 genes,e leven genes were localized on chromosome 19, 6 on chromosome 1, 2, 16, 17 respectively. No abnormal differentially expressed gene were detected on chromosome 5, 14, 22 and Y.These 71 genes differentially expressed both in tumor tissues and paratumor mucosa may be associated with carcinogenesis of gastric carcinoma. The four kinds of genes associated with enzyme and enzyme regulon activity, nuclei acid binding activity, signal transduction, and protein binding should be the main genes for the study of carcinogenesis in gastric carcinoma.

Arabidopsis thaliana contains five identified blue light photoreceptors and at least one unidentified blue/UV-A light photoreceptor. Cryptochromes (CRY1 and CRY2) modulate photomorphological processes, flowering time, and circadian timing while phototrophins (PHOT1 and PHOT2) modulate phototropism, chloroplast movement, and stomatal opening. Flavins are the chromophores and absorb in the blue and UV-A range. Considerable information is known about the structure and mode of action of these photoreceptors. The moss Physcomitrella patens contains two identified cryptochromes (CRY1a and CRY1b) which modulate side branch formation and auxin metabolism. Blue light-induced chloroplast movement was mediated by four phototropins. Transduction of the blue/UV-A stimulus does involve calcium signaling in moss cells.

To study the difference of gene expression profiles in gastric cancer (T), pericancerous mucosa (P) and the gastric mucosa from distant cutting margin (C), and to screen an associated novel gene in early gastric carcinogenesis by oligonucleotide microarray.U133A (Affymetrix, Santa Clara, CA) gene chip was used to detect the gene expression profile difference in T, P and C, respectively. Bioinformatics was used to analyze the detected results.When gastric cancer was compared with normal gastric mucosa, 766 genes were found,with a difference of more than four times in expression levels, including 530 up-regulated [Signal Log Ratio (SLR)2], and 236 down-regulated (SLR-2). When P was compared with C, 64 genes were found, with a difference of more than four times in expression levels, including 50 up-regulated (SLR2), and 14 down-regulated (SLR-2). Compared with C, a total of 143 genes with a difference of more than four times in expression levels both in T and P tissues. Of the 143 genes, 108 were up-regulated (SLR2), and 35 were down-regulated (SLR-2).Gene chip can reveal 143 same genes both in pericancerous mucosa and gastric mucosa. These genes may be related to the carcinogenesis and development of early gastric cancer.

Plant cells response to water deficit through a variety of physiological processes. In this work, we studied the function of microtubule cytoskeleton during dehydration/rehydration cycle in moss (Atrichum undulatum) protonemal cells as a model system. The morphological and cytological change of protonemal cells during dehydration and rehydration cycle were first investigated. Under normal conditions, protonemal cells showed bright green colour and appeared wet and fresh. Numerous chloroplasts distributed regularly throughout the cytoplasm in each cell. After dehydration treatment, protonemal cells lost most of their chlorophylls and turned to look yellow and dry. In addition, dehydration caused plasmolysis in these cells. Upon rehydration, the cells could recover completely from the dehydrated state. These results indicated that moss had a remarkable intrinsic ability to survive from the extreme drought stress. Microtubule, an important component of cytoskeleton, is considered to play crucial roles in the responses to some environmental stresses such as cold and light. To see if it is also involved in the drought tolerance, dynamic organization of microtubules in protonemal cells of Atrichum undulatum subjected to drought and rehydration were examined by indirect immunofluorescence combined with confocal lasersharp scanning microscopy. The cortical microtubules were arranged into a fine structure with a predominant orientation parallel to the long axis of the cells in the control cells. After dehydration, the microtubule organization was remarkablly altered and the fine microtubule structure disappeared whereas some thicker cables formed. When the cells were grown under rehydration conditions, the fine microtubule arrays reappeared. These results provided a piece of evidence that microtubules play a role in the cellular responses to drought stress in moss. Furthermore, we analyzed the effects of the microtubule-disrupting agent colchicine on the morphology recovery of the protonemal cells during rehydration process. The cells were incubated with colchicine, followed by drought stress treatment and rehydration in the presence of colchicine to prevent recovery of microtubule organization. Results from immunofluorescence showed that microtubule arrays were broken down into smaller fragments. Compared to the cells treated with drought stress alone, the cells treated with drought stress in the presence of colchicine could not recover after rehydration treatment. The morphology resembled those of the drought treated cells, with obvious plasmolysis phenomena and loss of chlorophyll content. These results support the notion that microtubules were involved in the deccication tolerance mechanism in Atrichum undulatum.

To establish a human lung cancer cell line expressing human interferon-gamma.The full-length gene of human interferon-gamma (IFN-gamma) was introduced into the human lung adenocarcinoma cell line A549 through retroviral vector pLXSN. The established cell line A549-IFN-gamma was tested for expression of MHC class I and class II by flow cytometer (FCM) and tested for expression of IFN-gamma by enzyme-lined immunoadsorbent assay (ELISA ). The tumorigenesis of cell line A549-IFN-gamma was tested on nude mice.A high level of IFN-gamma protein was detected in the culture supernatants of cell line A549-IFN-gamma. The expressions of MHC class I and class II on A549-IFN-gamma cells increased significantly (P0.01), when compared with parental cell line A549. However, there was no significant difference (P0.05) between the growth of cell line A549-IFN-gamma and A549. Finally, the tumorigenesis test showed that A549-IFN-gamma had lower tumorigenetic effects than A549.The results indicate that introduction of human IFN-gamma gene into cell line A549 could increase its immunogenicity and decrease its tumorigenesis. With the established cell line A549-IFN-gamma, a tumor vaccine for human lung cancer may be developed.