The leaves of Bt (Bacillus thuringiensis) transgenic poplar (Populus nigra L.) and CpTI (Cowpea trypsin inhibitor) transgenic poplar ((P. tomentosa×P. bolleana)×P. Tomentosa) were taken to feed the 4th-5th-i...The leaves of Bt (Bacillus thuringiensis) transgenic poplar (Populus nigra L.) and CpTI (Cowpea trypsin inhibitor) transgenic poplar ((P. tomentosa×P. bolleana)×P. Tomentosa) were taken to feed the 4th-5th-instar larvae of American white moth (Hyphantria cunea (Drury)) for determination of the activities of the protective enzyme system inside larvae’s body. The physiological and biochemical effects of the transgenic poplars on the larvae were studied. The results showed that the two kinds of transgenic poplars had similar effects on the protective enzyme system in the midgut of larvae. The activities of superoxide dismutase, catalase, and peroxidase in midgut of the larvae increased gradually, reached the highest value at a certain time, and then decreased suddenly. For the larvae that were fed with the leaves of Bt transgenic poplar, the peak value of superoxide dismutase and catalase presented at the time of 24-h feeding, while the peak of peroxidase took place at the time of 12-h feeding. The activities of these protective enzymes for the larvae that were fed with leaves of CpTI transgenic poplar peaked 12 h later than that of those fed with leaves of Bt transgenic poplar. The comparison of activities of the protective enzymes was also carried out between the larvae with different levels of intoxication. It was found that the activities of protective enzyme of the seriously intoxicant larvae were higher than that of the lightly intoxicant larvae. This difference was more obvious in the group treated with CpTI transgenic poplar.展开更多
Photodynamic therapy(PDT) employs accumulation of photosensitizers(PSs) in malignant tumor tissue followed by the light-induced generation of cytotoxic reactive oxygen species to kill the tumor cells. The success of P...Photodynamic therapy(PDT) employs accumulation of photosensitizers(PSs) in malignant tumor tissue followed by the light-induced generation of cytotoxic reactive oxygen species to kill the tumor cells. The success of PDT depends on optimal PS dosage that is matched with the ideal power of light. This in turn depends on PS accumulation in target tissue and light administration time and period.As theranostic nanomedicine is driven by multifunctional therapeutics that aim to achieve targeted tissue delivery and image-guided therapy, fluorescent PS nanoparticle(NP)accumulation in target tissues can be ascertained through fluorescence imaging to optimize the light dose and administration parameters. In this regard, zebrafish larvae provide a unique transparent in vivo platform to monitor fluorescent PS bio-distribution and their therapeutic efficiency. Using fluorescent PS NPs with unique aggregation-induced emission characteristics, we demonstrate for the first time the real-time visualization of polymeric NP accumulation in tumor tissue and, more importantly, the best time to conduct PDT using transgenic zebrafish larvae with inducible liver hyperplasia as an example.展开更多
Extensive planting of Bacillus thuringiensis （Bt）-transgenic plants economically benefits society; how-ever, the potential risk they pose is receiving increasing attention. This study used enzyme-linked immunosorben...Extensive planting of Bacillus thuringiensis （Bt）-transgenic plants economically benefits society; how-ever, the potential risk they pose is receiving increasing attention. This study used enzyme-linked immunosorbent assay and fluorescence quantitative PCR （RT-PCR） to monitor the temporal and spatial dynamics of the expression of Bt toxic protein in a forest of 6- to 8-year-old trees of transgenic insect-resistant poplar 741 for three consec- utive years. The enrichment, distribution, and degradation of Bt toxic protein and the influence of transgenic poplars on the targeted insect population, Hyphantria cunea, were investigated. The content of CrylAc toxic protein dynamically changed in transgenic poplar. During the annual growth cycle, the content initially increased, then decreased in the long and the short branches of the crown and in the root system, peaking in August. During the study, the protein did not accumulate overtime. The mRNA transcription of gene CrylAc was almost consistent with the level of the protein, but transcription peaked in July. In the transgenic and control forestland, microscale levels of the CrylAc toxic protein were detected from the soil, but increased accumulation was not observed with the planting year of transgenic poplar. Meanwhile, Bt was isolated and detected molecularly from the soil in the experimental forestland. A systematic investigation of the density of H. cunea in the experimental transgenic poplar forest indi- cated that transgenic Pb29 poplar could resist insects to a certain degree. At peak occurrence of the targeted insects, the density of H. cunea in the experimental forest was significantly lower than in the nontransgenic poplar forest.展开更多
Transgenic trees as a new source for biofuel have brought a great interest in tree biotechnology. Genetically modifying forest trees for ethanol production have advantages in technical challenges, costs, environmental...Transgenic trees as a new source for biofuel have brought a great interest in tree biotechnology. Genetically modifying forest trees for ethanol production have advantages in technical challenges, costs, environmental concerns, and financial problems over some of crops. Genetic engineering of forest trees can be used to reduce the level of lignin, to produce the fast-growing trees, to develop trees with higher cellulose, and to allow the trees to be grown more widely. Trees can establish themselves in the field with less care of farmers, compared to most of crops. Transgenic crops as a new source for biofuel have been recently reviewed in several reviews. Here, we overview transgenic woody plants as a new source for biofuel including genetically modified woody plants and environment; main focus of woody plants genetic modifications; solar to chemical energy transfer; cellulose biosynthesis; lignin biosynthesis; and cellulosic ethanol as biofuel.展开更多
To have a preliminary insight into biosafety of genetically transformed hybrid triploid poplars （Populus tomentosa × P bolleana）× P. tomentosa with the cowpea trypsin inhibitor （CpTD gene, two layers of r...To have a preliminary insight into biosafety of genetically transformed hybrid triploid poplars （Populus tomentosa × P bolleana）× P. tomentosa with the cowpea trypsin inhibitor （CpTD gene, two layers of rhizospheric soil （from 0 to 20cm deep and from 20 to 40cm deep, respectively） were collected for microorganism culture, counting assay and PCR analysis to assess the potential impact of transgenic poplars on non-target microorganism population and transgene dispersal. When the same soil layer of suspension stock solution was diluted at both 1：1000 and 1：10000 rates, there were no significant differences in bacterium colony numbers between the inoculation plates of both transgenic and non-transgenic poplars. The uniform results were revealed for both soil layer suspension solutions of identical poplars at both dilution rates except for non-transgenic poplars at 1：10000 dilution rates from the same type of soil. No significant variation in morphology of both Gram-positive and Gram-negative bacteria was observed under the microscope. The potential transgene dispersal from root exudates or fallen leaves to non-target microbes was repudiated by PCR analysis, in which no CpTI gene specific DNA band was amplified for 15 sites of transgenic rhizospheric soil samples. It can be concluded that transgenic poplar with the CpTI gene has no severe impact on rhizospheric microorganisms and is tentatively safe to surrounding soil micro-ecosystem.展开更多
The possible horizomal transfer of transgenes is of great concern when the transgenic plants are released imo the field. To test the possible transfer of nptII of transgenic trees into soil bacteria, we have used a st...The possible horizomal transfer of transgenes is of great concern when the transgenic plants are released imo the field. To test the possible transfer of nptII of transgenic trees into soil bacteria, we have used a stool DNA preparation kit to isolate the DNA from the soils in the rhizospheres of two non- and eight transgenic Eucalyptus camaldulensis trees. All the samples have provided the corresponding PCR products in the amplification with bacterial 16S RNA specific sequences, which indicates that the quality of the isolated DNA is adequate for amplification. The nptⅡ specific band has been amplified in three soil samples from the transgenic trees and even treated with filtration before the DNA isolation. This indicates that nptII DNA exists in the soil, although it is still unclear whether the DNA was in the soil particles, in the soil bacteria or in the Agrobacterium comamination which was used for the E. camaldulensis transformation. Two approaches on isolation of bacterial DNA have been suggested for testing the possibility of this event in the future.展开更多
Objective ： To construct plant transformation vector containing Escherichia coli heat-labile enterotoxin B subunit （LT-B） gene and generate LT-B transgenic tobacco plants. Methods： The LT-B coding sequence was amp...Objective ： To construct plant transformation vector containing Escherichia coli heat-labile enterotoxin B subunit （LT-B） gene and generate LT-B transgenic tobacco plants. Methods： The LT-B coding sequence was amplified from pMMB68 by PCR, subcloned into middle vector pUCmT and binary vector pBI121 to obtain plant expression vector pBI-LTB, in which LT-B expression was controlled under the Cauliflower mosaic virus （CaMV） 35S promoter. The tobacco plants （Nicotiana tobacum L. Cuttivar Xanthi） were transformed by co-cultivating leaf discs method via Agrobacterium tumefaciens LBA4404 harboring the plant expression vector. The regenerated transgenic tobacco plants were selected by kanamycin and confirmed by PCR, Southern blot, Western blot and ELISA. Resuits： LT-B gene integrated in the tobacco genomic DNA and were expressed in 9 strains of transgenic tobacco plants. The yield was varied from 3. 36-10. 56 ng/mg total soluble tobacco leaf protein. Conclusion： The plant binary expression vector pBI-LTB was constructed successfully, and transgenic LT-B tobacco plants was generated, and confirmed by Southern blot. The protein LT-B expressed by engineered plants was identified by Western blot analysis and had the expected molecular weight of LT-B pentamer protein. This result is an important step close to developing an edible vaccine and supplying a mucasal immunoajuvant, which will contribute to the preven- tion of mucosaroute evading pathogen.展开更多
Laboratory feeding experiments with the poplar aphid, Chaitophorus populeti （Panzer）, feeding on transgenic poplar （P. alba × P. glandulosa） varieties C13-5 and C013-5, were carried out to study the effect of...Laboratory feeding experiments with the poplar aphid, Chaitophorus populeti （Panzer）, feeding on transgenic poplar （P. alba × P. glandulosa） varieties C13-5 and C013-5, were carried out to study the effect of transgenic poplar on the ladybird Harmonia axyridis （Pallas）. The mortality and development time of the immature stages, the eclosion rate and body mass of H. axyridis were measured. The results indicated that C. populeti feeding on different varieties of transgenic plants had no statistically significant ef- fect on the mortality ofH. axyridis larvae. The development time of larval and pupal stages were not significantly different between the two transgenic poplars and a non-transgenic poplar. Furthermore, the body mass and eclosion rate did not show any difference between the H. axyridis feeding on aphids reared on transgenic plants and those from non-transgenic plants. It is suggested that transgenic plants have no deleterious effect on the predatory ladybird.展开更多
Cellulose is one of many important polymers in plants. Cellulose is made of repeat units of the monomer glucose. Cellulose is a major industrial biopolymer in the forest products, textile, and chemical industries. It ...Cellulose is one of many important polymers in plants. Cellulose is made of repeat units of the monomer glucose. Cellulose is a major industrial biopolymer in the forest products, textile, and chemical industries. It also forms a large portion of the biomass useful in the generation of energy. Moreover, cellulose-based biomass is a renewable energy source that can be used for the generation of ethanol as a fuel. Cellulose is synthesized by a variety of living organisms such as plants and algae. It is the major component of plant cell walls with secondary cell walls having a much higher content of cellulose. The relationship between cellulose and lignin biosynthesis is complicated, but it is confirmed that inhibition of lignin biosynthesis in transgenic trees will increase cellulose biosynthesis and plant growth. Cellulose accumulation may be increased by down-regulating 4-coumarate:coenzyme A ligase (4CL, EC 6.2.1.12) as shown in transgenic aspen. There is no similar reports on down-regulating 4CL in transgenic conifers. Based on our established Agrobacterium tumefaciens-mediated transformation system in loblolly pine, we are able to produce antisense 4-CL transgenic loblolly pine which is predicted to have increas- ing cellulose accumulation. The overall objective of this project is to genetically engineer forest tree species such as loblolly pine with re- duced amount of lignin and increased cellulose content. The research strategy includes: (1) isolate the 4-coumarate:coenzyme A ligase gene from loblolly pine seedlings by reverse transcription-polymerase chain reaction (RT-PCR) and Rapid Amplification of cDNA Ends-Polymerase Chain Reaction (RACE-PCR) techniques from the cDNA library; (2) construct binary expression vectors with antisense 4CL coding sequences and introduce antisense constructs of the 4-coumarate:coenzyme A ligase gene cloned from loblolly pine into the loblolly pine to down regulate the 4-coumarate:coenzyme A ligase gene expression; (3) study the effect of the antisense transgene expres- sion on lignin content, cellulose accumulation, and loblolly pine biomass; and (4) select fast growth and high cellulose accumulation transgenic loblolly pine lines for future commercial application.展开更多
Objective: To establish transgenic mouse lineages containing copies of a stably integratedpSPORT1 plasmid by microinjection into fertilized eggs and to provide an efficient animal model for studyinggene mutations in v...Objective: To establish transgenic mouse lineages containing copies of a stably integratedpSPORT1 plasmid by microinjection into fertilized eggs and to provide an efficient animal model for studyinggene mutations in vivo. Methods and Results: 2594 fertilized eggs from KM white mice were injected withpSPORT1 DNA and transferred into the oviducts of 103 pseudopregnant females. from which 237 offspringswere obtained. 40 of these offsprings were identified positive for the forgeign gene by PCR analysis and 38were reproved positive by Southern blot analysis. Finally, eight of the stout mice whose genornes were integrated with intact pSPORT1 vectors, verified by Southern blotting analysis, were chosen as founders to establish the transgenic mouse lineages. The experimental results inchoated that the pregnant rate of recipientfemales and the Positive rate of offsprings were dramatically influenced by the structure of the transgene(linearized or circular ) and the mode of egg-transfer. The integration rate of linearized transgene was significantly higher than that of the circular transgene,and female with two-side oviduct transfer of fertilized eggs waseasy to have baby mice. Conclusion: (1 ) Transgenic mouse lineages containing copies of a stably integratedPSPORT 1 plasmid were established; (2 ) The linearized transgene and two-side oviduct transfer of fertilizedeggs is more efficient in preparing transgenic mice.展开更多
The role of late embryogenesis abundant （LEA） proteins in stress tolerance was examined by using a yeast expression system. LEA protein tolerance to the abotic stresses in plants involved in salt, drought and freezi...The role of late embryogenesis abundant （LEA） proteins in stress tolerance was examined by using a yeast expression system. LEA protein tolerance to the abotic stresses in plants involved in salt, drought and freezing stresses and additional tolerance to heat, NaHCO3 （salt-alkali） and ultraviolet radiation was also investigated. The transgenic yeast harboring the Tamarix LEA gene （DQ663481） was generated under the control of inducible GAL promoter （pYES2 vector）, yeast cells transformed with pYES2 empty vector were also generated as a control. Stress tolerance tests showed that LEA yeast transformants exhibited a higher survival rates than the control transformants under high temperature, NaHCO3, ultraviolet radiation, salt （NaCl）, drought and freezing, indicating that the LEA gene is tolerant to these abiotic stresses. These results suggest that the LEA gene is resistant to a wider repertoire of stresses and may play a common role in plant acclimation to the examined stress conditions.展开更多
Cardiomyopathies are diseases that primarily affect the myocardium, leading to serious cardiac dysfunction and heart failure. Out of the three major categories of cardiomyopathies （hypertrophic, dilated and restrict...Cardiomyopathies are diseases that primarily affect the myocardium, leading to serious cardiac dysfunction and heart failure. Out of the three major categories of cardiomyopathies （hypertrophic, dilated and restrictive）, restrictive cardiomyopathy （RCM） is less common and also the least studied. However, the prognosis for RCM is poor as some patients dying in their childhood. The molecular mechanisms behind the disease development and progression are not very clear and the treatment of RCM is very difficult and often ineffective. In this article, we reviewed the recent progress in RCM research from the clinical studies and the translational studies done on diseased transgenic animal models. This will help for a better understanding of the mechanisms underlying the etiology and development of RCM and for the design of better treatments for the disease.展开更多
BACKGROUND： Apoptosis plays an important role in central neural diseases and trauma. B-cell lymphoma/Leukemia-2 （Bcl-2） can inhibit apoptosis in a wide variety of cells including neurons. In this experiment, by stu...BACKGROUND： Apoptosis plays an important role in central neural diseases and trauma. B-cell lymphoma/Leukemia-2 （Bcl-2） can inhibit apoptosis in a wide variety of cells including neurons. In this experiment, by studying Bcl-2 over-expression transgenic （TG） mice subjected to spinal cord injury （SCI）, we investigated whether Bcl-2 could reduce posttraumatic neuronal apoptosis, reduce the range of damage, and improve the behavioral functional recovery after contusive SCI.METHODS： Nine Bcl-2 TG mice and nine control mice were subjected to SCI of moderate severity at T10, with the use of weight dropping （WD） method （impact force 2.5×3.0 g/cm）. At times up to 1 day, 7 days and 14 days after SCI, functional defi cits were evaluated with Basso, Beattie, and Bresnahan （BBB） scales, and apoptosis of neurons was investigated by using the TUNEL method. Another three control mice only underwent lamina opening, but were not subjected to SCI, to provide blank comparison.RESULTS： The mean functional scores for the control mice （5.05 ±0.35） were lower than those for the Bcl-2 TG mice （5.45 ±0.15）, although the unpaired T-test revealed no signifi cant difference （P=0.67）. On the other hand, the number of TUNEL positive neurons and integrated option density （IOD） scores for the Bcl-2 TG mice were both signifi cantly lower than those for the control mice （P〈0.05）.CONCLUSIONS： This experiment suggests that overexpression of Bcl-2 may suppress neuronal apoptosis after SCI. Bcl-2 may be an important factor within the central nervous system that can relieve the damage after trauma.展开更多
The VirE2-interaction protein 1(VIP1)serves as a regulator of mitogen-activated protein kinase 3(MPK3)-mediated stress gene modulation under biotic stress,which in turn activates the MPK3 pathway in Arabidopsis.The mo...The VirE2-interaction protein 1(VIP1)serves as a regulator of mitogen-activated protein kinase 3(MPK3)-mediated stress gene modulation under biotic stress,which in turn activates the MPK3 pathway in Arabidopsis.The mode of action of the VIP1 protein in Populus in response to biotic stress remains unknown.In this study,we cloned the full-length cDNA of the PtVIP1 gene from Populus trichocarpa(accession number of GenBank:KY793105).The VIP1 protein harboured a conserved bZIP(basic leucine zipper)domain located in the C-terminus.The VIP1 subcellular localization assay indicated that the VIP1 protein was present in the cytoplasm and nucleus under normal conditions,and that an increase in the amount of the protein in the nucleus occurred after treatment with flg22,the elicitor-active epitope of flagellin which triggers the innate immune response in plants.Transgenic Populus plants overexpressing VIP1 genes(PtVIP1 of Populus;or AtVIP1 of Arabidopsis,as positive control)were generated to investigate the role of VIP1 in vivo.The expression of poplar pathogenesis-related protein 1(PR1)genes was upregulated in transgenic-PtVIP1 or AtVIP1 poplar plants.The transgenic poplar plants overexpressing PtVIP1 or AtVIP1 also showed enhanced resistance to Brenneria salicis infection.These results suggest that the VIP1 protein accumulates in the nucleus in response to biotic stress,and that the pathogen resistance of transgenic VIP1 poplar may be associated with the induced expression of PR1 genes in response to pathogen challenge.展开更多
Objective To characterize early afterdepolarizations （EADs） caused triggered activity （TA） among calsequestrin-2 （CASQ2） knock-in （CASQ2 KI） mice and its relationship with aging. Methods Electrophysiological p...Objective To characterize early afterdepolarizations （EADs） caused triggered activity （TA） among calsequestrin-2 （CASQ2） knock-in （CASQ2 KI） mice and its relationship with aging. Methods Electrophysiological properties of ventricular myocytes from 3- month （mo, young）, 9-mo （adult-l） and 12-too （adult-2） in wild-type （WT） and CASQ2 KI mice were investigated with patch-clamp technique. Results The incidences of EADs and TA in CASQ2 KI cardiomyocytes increased with increasing age. In contrast, WT mice cardiomyocytes showed no significant change in matched-age groups. Compared with that in 3-mo CASQ2 KI mice, the 50% repolarization of action potential （APD50） showed prolongation in both 9-mo and 12-mo ones （9.2±0.9 ms of 9-mo and 10.3 ± 1.2 ms of 12- mo vs. 5.6± 0.3 ms of 3-mo）, while the 90 % repolarization of action potential （APD90） was similar among 3 age groups. Compared with 3-mo mice, the 9-mo and 12-mo CASQ2 KI mice showed markedly reduced transient outward potassium current （Ito） densities but increased L-type calcium current （ICa-L） densities. Conlcusion This study suggested that events of EADs and TA in CASQ2 KI mice increased with increasing age, It might be associated partly with the augment of cellular calcium concentration and the prolongation of APD50 induced by decrease of Ito and increase of ICa-L in adult CASQ2 KI mice展开更多
Genetic engineering of forest tree species is regarded as a strategy to reduce worldwide pressure on natural forests, to conserve genetic resources and ameliorate stress on global climate, and to meet growing demand f...Genetic engineering of forest tree species is regarded as a strategy to reduce worldwide pressure on natural forests, to conserve genetic resources and ameliorate stress on global climate, and to meet growing demand for forest wood and timber products. Genetic engineering approaches toward the control or management of fungal pathogens, arthropod herbivores, bacterial and viral diseases, the use of pest resistance genes, and weed competitors are being studied. Although the production of transgenic trees is relatively recent and only a few species have been successfully genetically engineered in forest tree species, very useful and valuable information is available on the application of transgenic trees. Genes involved in important agricultural traits such as herbicide resistance, insect resistance, and wood quality have been isolated and have been used to genetically engineer trees. New technologies of plant molecular biology and genomics now make it possible high-efficient genetic improvement of forest trees. Genetic engineering promises to expand greatly the potential for genetic manipulation as new genes of commercial interest are discovered and utilized. Lignification is a process essential to the nature and evolution of vascular plants that is still poorly understood, even though it has been studied for more than a century. Recent studies on mutant and transgenic plants indicate that lignification may be far more flexible than previously realized. Rines with a mutation affecting the biosynthesis of the major lignin precursor, coniferyl alcohol, show a high level of an unusual subunit, dihydroconiferyl alcohol. It is also unusual as a plant polymer in that there are no plant enzymes for its degradation. These results have significant implications regarding the tradiational definition of lignin, and highlight the need for a better understanding of the lignin precursor biosynthetic pathway. In this review, we describe the progress made recently in genetic engineering of forest tree species.展开更多
A 3 125 bp cellulose synthase gene, PtoCesA1, which has a 98% identity to PtrCesA1 from Populus tremuloides, was cloned from cDNA prepared from secondary xylem of P tomentosa. Four anti-expression vectors with differe...A 3 125 bp cellulose synthase gene, PtoCesA1, which has a 98% identity to PtrCesA1 from Populus tremuloides, was cloned from cDNA prepared from secondary xylem of P tomentosa. Four anti-expression vectors with different fragments of PtoCesAl, named as pBIPF, pBICC1, pBIPR and pBIBR, were constructed. Some traits of transformed tobacco of pBICC1, pBIPR and pBIBR differed from wild types, such as small leaves, ＂dwarf＂ phenotype and thinner xylem and fiber cell walls than wild plants consistent with a loss of cellulose. It indicated that the growth of transgenic tobacco was restrained by the expression of anti-PtoCesA1. Transgenic tobacco was obtained and the contents of cellulose and lignin were analyzed as well as the width and length of fiber cells, and xylem thickness for both transgenic and control plants. Transformed tobacco showed a different phenotype from control plants and it implied that PtoCesA1 was essential for the cellulose biosynthesis in poplar stems.展开更多
The ethylene-responsive factor family is one of the largest families of plant-specific transcription factors that are involved in plant development and stress responses. Previously, we demonstrated that the gene Th ER...The ethylene-responsive factor family is one of the largest families of plant-specific transcription factors that are involved in plant development and stress responses. Previously, we demonstrated that the gene Th ERF1,encoding a novel ethylene-responsive factor from Tamarix hispida, negatively modulates abiotic stress tolerance. In the present study, Arabidopsis plants overexpressing Th ERF1 had decreased oxidative tolerance and increased transpirational water loss rate compared with wild-type plants, leading to sensitivity to abiotic stress. Real-time RT-PCR showed that the upstream regulator of Th ERF1,Th WRKY2, is involved in responses to different abiotic stresses. Furthermore, both Th WRKY2 and Th ERF1 shared similar expression patterns in the stems and leaves of T.hispida when exposed to salinity, drought and abscisic acid. Chromatin immunoprecipitation assays further confirmed that Th WRKY2 can directly bind to the promoter of Th ERF1 and regulate its expression. This study revealed the regulatory mechanism of Th ERF1 expression in response to abiotic stresses in T. hispida.展开更多
SQUAMOSA-promoter binding protein-like (SPL) proteins are plant-specific transcription factors and participate in different pathways, including the vegetative to reproductive transition, male sterility, biosynthesis o...SQUAMOSA-promoter binding protein-like (SPL) proteins are plant-specific transcription factors and participate in different pathways, including the vegetative to reproductive transition, male sterility, biosynthesis of gibberellic acid (GA), plant morphogenesis and response to environmental stress. In this study, we generated transgenic Arabidopsis that overexpressed Betula BplSPL8 and confirmed that BplSPL8 is a transcription factor with transcriptional activation activity and is located in the nucleus. Functional analysis of BplSPL8 showed that it is involved in regulating different development processes: (1) BplSPL8 can delay flowering by reducing sensitivity to GA under short days; (2) BplSPL8 controls the number and morphogenesis of leaves, including up-rolling leaves under long days and folded leaves mediated by GA under short days; (3) BplSPL8 can promote root elongation during late development of roots and inhibit lateral root formation; (4) BplSPL8 may be involved in regulating carotenoid biosynthesis and secretion metabolism. These results show that there is a complex regulatory network for the SPL family genes that is mediated by other components and may provide a new insights for the functional research of SPL genes.展开更多
With specific designed prmers. CYP2B6 and CYP1A1 cDNA were generatecl by reverse transcrlI7tion-Polymerase chain reaction(RT-PCR )technlque Performed on total RNAs isolated frorn hum1ln liver and 3-rnethylch(,lanthren...With specific designed prmers. CYP2B6 and CYP1A1 cDNA were generatecl by reverse transcrlI7tion-Polymerase chain reaction(RT-PCR )technlque Performed on total RNAs isolated frorn hum1ln liver and 3-rnethylch(,lanthrene(3-Mtt)induc human amnion FL, cells. Cell llnes (CHL, 2B6 and CtHL-1A1 ) capableof expressing hunlan cytochome P 15O (CYP ) 2B6 and 1A1 were establishecl after transfection of corre-sponding eukaryotic reconlbinant expression plasmid with human CYP2ll6 and 1A1 cDNA lnserts respectlvely. These cell lines stably expressed the mRNAs and the enzymatic activltles cc)rresI’onding to ttYP2B6and CYP1A1, respectively’ Compared with Chinese hamster lung (CHL) cells, the n1icr()nucleus frecluencyin CHl,-2B6 cells is markedly lncreased when exPosed to nitrosamines,aflatoxln B, (AFB1) and cyclophos-Phamide (CPA). Thls is also in CHL-1A1 cells,when exposed to carcinogenic polycycllc aromatic hydrocar-bons.展开更多
文摘The leaves of Bt (Bacillus thuringiensis) transgenic poplar (Populus nigra L.) and CpTI (Cowpea trypsin inhibitor) transgenic poplar ((P. tomentosa×P. bolleana)×P. Tomentosa) were taken to feed the 4th-5th-instar larvae of American white moth (Hyphantria cunea (Drury)) for determination of the activities of the protective enzyme system inside larvae’s body. The physiological and biochemical effects of the transgenic poplars on the larvae were studied. The results showed that the two kinds of transgenic poplars had similar effects on the protective enzyme system in the midgut of larvae. The activities of superoxide dismutase, catalase, and peroxidase in midgut of the larvae increased gradually, reached the highest value at a certain time, and then decreased suddenly. For the larvae that were fed with the leaves of Bt transgenic poplar, the peak value of superoxide dismutase and catalase presented at the time of 24-h feeding, while the peak of peroxidase took place at the time of 12-h feeding. The activities of these protective enzymes for the larvae that were fed with leaves of CpTI transgenic poplar peaked 12 h later than that of those fed with leaves of Bt transgenic poplar. The comparison of activities of the protective enzymes was also carried out between the larvae with different levels of intoxication. It was found that the activities of protective enzyme of the seriously intoxicant larvae were higher than that of the lightly intoxicant larvae. This difference was more obvious in the group treated with CpTI transgenic poplar.
基金financial support from National Research Foundation Investigatorship (R279-000-444-281)National University of Singapore (R279-000-482-133)
文摘Photodynamic therapy(PDT) employs accumulation of photosensitizers(PSs) in malignant tumor tissue followed by the light-induced generation of cytotoxic reactive oxygen species to kill the tumor cells. The success of PDT depends on optimal PS dosage that is matched with the ideal power of light. This in turn depends on PS accumulation in target tissue and light administration time and period.As theranostic nanomedicine is driven by multifunctional therapeutics that aim to achieve targeted tissue delivery and image-guided therapy, fluorescent PS nanoparticle(NP)accumulation in target tissues can be ascertained through fluorescence imaging to optimize the light dose and administration parameters. In this regard, zebrafish larvae provide a unique transparent in vivo platform to monitor fluorescent PS bio-distribution and their therapeutic efficiency. Using fluorescent PS NPs with unique aggregation-induced emission characteristics, we demonstrate for the first time the real-time visualization of polymeric NP accumulation in tumor tissue and, more importantly, the best time to conduct PDT using transgenic zebrafish larvae with inducible liver hyperplasia as an example.
基金supported by the National High Technology Research and Development Program of China(863 Program)(Grant No.2013AA102703)
文摘Extensive planting of Bacillus thuringiensis （Bt）-transgenic plants economically benefits society; how-ever, the potential risk they pose is receiving increasing attention. This study used enzyme-linked immunosorbent assay and fluorescence quantitative PCR （RT-PCR） to monitor the temporal and spatial dynamics of the expression of Bt toxic protein in a forest of 6- to 8-year-old trees of transgenic insect-resistant poplar 741 for three consec- utive years. The enrichment, distribution, and degradation of Bt toxic protein and the influence of transgenic poplars on the targeted insect population, Hyphantria cunea, were investigated. The content of CrylAc toxic protein dynamically changed in transgenic poplar. During the annual growth cycle, the content initially increased, then decreased in the long and the short branches of the crown and in the root system, peaking in August. During the study, the protein did not accumulate overtime. The mRNA transcription of gene CrylAc was almost consistent with the level of the protein, but transcription peaked in July. In the transgenic and control forestland, microscale levels of the CrylAc toxic protein were detected from the soil, but increased accumulation was not observed with the planting year of transgenic poplar. Meanwhile, Bt was isolated and detected molecularly from the soil in the experimental forestland. A systematic investigation of the density of H. cunea in the experimental transgenic poplar forest indi- cated that transgenic Pb29 poplar could resist insects to a certain degree. At peak occurrence of the targeted insects, the density of H. cunea in the experimental forest was significantly lower than in the nontransgenic poplar forest.
基金supported by the East Carolina Christmas Tree Program
文摘Transgenic trees as a new source for biofuel have brought a great interest in tree biotechnology. Genetically modifying forest trees for ethanol production have advantages in technical challenges, costs, environmental concerns, and financial problems over some of crops. Genetic engineering of forest trees can be used to reduce the level of lignin, to produce the fast-growing trees, to develop trees with higher cellulose, and to allow the trees to be grown more widely. Trees can establish themselves in the field with less care of farmers, compared to most of crops. Transgenic crops as a new source for biofuel have been recently reviewed in several reviews. Here, we overview transgenic woody plants as a new source for biofuel including genetically modified woody plants and environment; main focus of woody plants genetic modifications; solar to chemical energy transfer; cellulose biosynthesis; lignin biosynthesis; and cellulosic ethanol as biofuel.
文摘To have a preliminary insight into biosafety of genetically transformed hybrid triploid poplars （Populus tomentosa × P bolleana）× P. tomentosa with the cowpea trypsin inhibitor （CpTD gene, two layers of rhizospheric soil （from 0 to 20cm deep and from 20 to 40cm deep, respectively） were collected for microorganism culture, counting assay and PCR analysis to assess the potential impact of transgenic poplars on non-target microorganism population and transgene dispersal. When the same soil layer of suspension stock solution was diluted at both 1：1000 and 1：10000 rates, there were no significant differences in bacterium colony numbers between the inoculation plates of both transgenic and non-transgenic poplars. The uniform results were revealed for both soil layer suspension solutions of identical poplars at both dilution rates except for non-transgenic poplars at 1：10000 dilution rates from the same type of soil. No significant variation in morphology of both Gram-positive and Gram-negative bacteria was observed under the microscope. The potential transgene dispersal from root exudates or fallen leaves to non-target microbes was repudiated by PCR analysis, in which no CpTI gene specific DNA band was amplified for 15 sites of transgenic rhizospheric soil samples. It can be concluded that transgenic poplar with the CpTI gene has no severe impact on rhizospheric microorganisms and is tentatively safe to surrounding soil micro-ecosystem.
文摘The possible horizomal transfer of transgenes is of great concern when the transgenic plants are released imo the field. To test the possible transfer of nptII of transgenic trees into soil bacteria, we have used a stool DNA preparation kit to isolate the DNA from the soils in the rhizospheres of two non- and eight transgenic Eucalyptus camaldulensis trees. All the samples have provided the corresponding PCR products in the amplification with bacterial 16S RNA specific sequences, which indicates that the quality of the isolated DNA is adequate for amplification. The nptⅡ specific band has been amplified in three soil samples from the transgenic trees and even treated with filtration before the DNA isolation. This indicates that nptII DNA exists in the soil, although it is still unclear whether the DNA was in the soil particles, in the soil bacteria or in the Agrobacterium comamination which was used for the E. camaldulensis transformation. Two approaches on isolation of bacterial DNA have been suggested for testing the possibility of this event in the future.
基金Supported by the National Natural Science Foundation ofChina (No. 30070848)
文摘Objective ： To construct plant transformation vector containing Escherichia coli heat-labile enterotoxin B subunit （LT-B） gene and generate LT-B transgenic tobacco plants. Methods： The LT-B coding sequence was amplified from pMMB68 by PCR, subcloned into middle vector pUCmT and binary vector pBI121 to obtain plant expression vector pBI-LTB, in which LT-B expression was controlled under the Cauliflower mosaic virus （CaMV） 35S promoter. The tobacco plants （Nicotiana tobacum L. Cuttivar Xanthi） were transformed by co-cultivating leaf discs method via Agrobacterium tumefaciens LBA4404 harboring the plant expression vector. The regenerated transgenic tobacco plants were selected by kanamycin and confirmed by PCR, Southern blot, Western blot and ELISA. Resuits： LT-B gene integrated in the tobacco genomic DNA and were expressed in 9 strains of transgenic tobacco plants. The yield was varied from 3. 36-10. 56 ng/mg total soluble tobacco leaf protein. Conclusion： The plant binary expression vector pBI-LTB was constructed successfully, and transgenic LT-B tobacco plants was generated, and confirmed by Southern blot. The protein LT-B expressed by engineered plants was identified by Western blot analysis and had the expected molecular weight of LT-B pentamer protein. This result is an important step close to developing an edible vaccine and supplying a mucasal immunoajuvant, which will contribute to the preven- tion of mucosaroute evading pathogen.
基金supported by the National Premier Special Funds for Study and Industrialization of Transgenic Plants (J2002-B-004)the National Natural Science and Technology Support Plan of China "the technology researchdemonstration of forestry-paper integrate project" (Grant No. 2006BAD32B)
文摘Laboratory feeding experiments with the poplar aphid, Chaitophorus populeti （Panzer）, feeding on transgenic poplar （P. alba × P. glandulosa） varieties C13-5 and C013-5, were carried out to study the effect of transgenic poplar on the ladybird Harmonia axyridis （Pallas）. The mortality and development time of the immature stages, the eclosion rate and body mass of H. axyridis were measured. The results indicated that C. populeti feeding on different varieties of transgenic plants had no statistically significant ef- fect on the mortality ofH. axyridis larvae. The development time of larval and pupal stages were not significantly different between the two transgenic poplars and a non-transgenic poplar. Furthermore, the body mass and eclosion rate did not show any difference between the H. axyridis feeding on aphids reared on transgenic plants and those from non-transgenic plants. It is suggested that transgenic plants have no deleterious effect on the predatory ladybird.
文摘Cellulose is one of many important polymers in plants. Cellulose is made of repeat units of the monomer glucose. Cellulose is a major industrial biopolymer in the forest products, textile, and chemical industries. It also forms a large portion of the biomass useful in the generation of energy. Moreover, cellulose-based biomass is a renewable energy source that can be used for the generation of ethanol as a fuel. Cellulose is synthesized by a variety of living organisms such as plants and algae. It is the major component of plant cell walls with secondary cell walls having a much higher content of cellulose. The relationship between cellulose and lignin biosynthesis is complicated, but it is confirmed that inhibition of lignin biosynthesis in transgenic trees will increase cellulose biosynthesis and plant growth. Cellulose accumulation may be increased by down-regulating 4-coumarate:coenzyme A ligase (4CL, EC 6.2.1.12) as shown in transgenic aspen. There is no similar reports on down-regulating 4CL in transgenic conifers. Based on our established Agrobacterium tumefaciens-mediated transformation system in loblolly pine, we are able to produce antisense 4-CL transgenic loblolly pine which is predicted to have increas- ing cellulose accumulation. The overall objective of this project is to genetically engineer forest tree species such as loblolly pine with re- duced amount of lignin and increased cellulose content. The research strategy includes: (1) isolate the 4-coumarate:coenzyme A ligase gene from loblolly pine seedlings by reverse transcription-polymerase chain reaction (RT-PCR) and Rapid Amplification of cDNA Ends-Polymerase Chain Reaction (RACE-PCR) techniques from the cDNA library; (2) construct binary expression vectors with antisense 4CL coding sequences and introduce antisense constructs of the 4-coumarate:coenzyme A ligase gene cloned from loblolly pine into the loblolly pine to down regulate the 4-coumarate:coenzyme A ligase gene expression; (3) study the effect of the antisense transgene expres- sion on lignin content, cellulose accumulation, and loblolly pine biomass; and (4) select fast growth and high cellulose accumulation transgenic loblolly pine lines for future commercial application.
文摘Objective: To establish transgenic mouse lineages containing copies of a stably integratedpSPORT1 plasmid by microinjection into fertilized eggs and to provide an efficient animal model for studyinggene mutations in vivo. Methods and Results: 2594 fertilized eggs from KM white mice were injected withpSPORT1 DNA and transferred into the oviducts of 103 pseudopregnant females. from which 237 offspringswere obtained. 40 of these offsprings were identified positive for the forgeign gene by PCR analysis and 38were reproved positive by Southern blot analysis. Finally, eight of the stout mice whose genornes were integrated with intact pSPORT1 vectors, verified by Southern blotting analysis, were chosen as founders to establish the transgenic mouse lineages. The experimental results inchoated that the pregnant rate of recipientfemales and the Positive rate of offsprings were dramatically influenced by the structure of the transgene(linearized or circular ) and the mode of egg-transfer. The integration rate of linearized transgene was significantly higher than that of the circular transgene,and female with two-side oviduct transfer of fertilized eggs waseasy to have baby mice. Conclusion: (1 ) Transgenic mouse lineages containing copies of a stably integratedPSPORT 1 plasmid were established; (2 ) The linearized transgene and two-side oviduct transfer of fertilizedeggs is more efficient in preparing transgenic mice.
基金National Key Program on Basic Research and Development of China (G1999016003)
文摘The role of late embryogenesis abundant （LEA） proteins in stress tolerance was examined by using a yeast expression system. LEA protein tolerance to the abotic stresses in plants involved in salt, drought and freezing stresses and additional tolerance to heat, NaHCO3 （salt-alkali） and ultraviolet radiation was also investigated. The transgenic yeast harboring the Tamarix LEA gene （DQ663481） was generated under the control of inducible GAL promoter （pYES2 vector）, yeast cells transformed with pYES2 empty vector were also generated as a control. Stress tolerance tests showed that LEA yeast transformants exhibited a higher survival rates than the control transformants under high temperature, NaHCO3, ultraviolet radiation, salt （NaCl）, drought and freezing, indicating that the LEA gene is tolerant to these abiotic stresses. These results suggest that the LEA gene is resistant to a wider repertoire of stresses and may play a common role in plant acclimation to the examined stress conditions.
文摘Cardiomyopathies are diseases that primarily affect the myocardium, leading to serious cardiac dysfunction and heart failure. Out of the three major categories of cardiomyopathies （hypertrophic, dilated and restrictive）, restrictive cardiomyopathy （RCM） is less common and also the least studied. However, the prognosis for RCM is poor as some patients dying in their childhood. The molecular mechanisms behind the disease development and progression are not very clear and the treatment of RCM is very difficult and often ineffective. In this article, we reviewed the recent progress in RCM research from the clinical studies and the translational studies done on diseased transgenic animal models. This will help for a better understanding of the mechanisms underlying the etiology and development of RCM and for the design of better treatments for the disease.
文摘BACKGROUND： Apoptosis plays an important role in central neural diseases and trauma. B-cell lymphoma/Leukemia-2 （Bcl-2） can inhibit apoptosis in a wide variety of cells including neurons. In this experiment, by studying Bcl-2 over-expression transgenic （TG） mice subjected to spinal cord injury （SCI）, we investigated whether Bcl-2 could reduce posttraumatic neuronal apoptosis, reduce the range of damage, and improve the behavioral functional recovery after contusive SCI.METHODS： Nine Bcl-2 TG mice and nine control mice were subjected to SCI of moderate severity at T10, with the use of weight dropping （WD） method （impact force 2.5×3.0 g/cm）. At times up to 1 day, 7 days and 14 days after SCI, functional defi cits were evaluated with Basso, Beattie, and Bresnahan （BBB） scales, and apoptosis of neurons was investigated by using the TUNEL method. Another three control mice only underwent lamina opening, but were not subjected to SCI, to provide blank comparison.RESULTS： The mean functional scores for the control mice （5.05 ±0.35） were lower than those for the Bcl-2 TG mice （5.45 ±0.15）, although the unpaired T-test revealed no signifi cant difference （P=0.67）. On the other hand, the number of TUNEL positive neurons and integrated option density （IOD） scores for the Bcl-2 TG mice were both signifi cantly lower than those for the control mice （P〈0.05）.CONCLUSIONS： This experiment suggests that overexpression of Bcl-2 may suppress neuronal apoptosis after SCI. Bcl-2 may be an important factor within the central nervous system that can relieve the damage after trauma.
基金supported by the National Natural Science Foundation of China(Grant No.31570639)the Distinguished Young Scholars Fund of Nanjing Forestry University,the Priority Academic Program Development of Nanjing Forestry University the Poplar Germplasm Nursery Project(Jiangsu Provincial Platform for Conservation and Utilizations for Agricultural Germplasm)
文摘The VirE2-interaction protein 1(VIP1)serves as a regulator of mitogen-activated protein kinase 3(MPK3)-mediated stress gene modulation under biotic stress,which in turn activates the MPK3 pathway in Arabidopsis.The mode of action of the VIP1 protein in Populus in response to biotic stress remains unknown.In this study,we cloned the full-length cDNA of the PtVIP1 gene from Populus trichocarpa(accession number of GenBank:KY793105).The VIP1 protein harboured a conserved bZIP(basic leucine zipper)domain located in the C-terminus.The VIP1 subcellular localization assay indicated that the VIP1 protein was present in the cytoplasm and nucleus under normal conditions,and that an increase in the amount of the protein in the nucleus occurred after treatment with flg22,the elicitor-active epitope of flagellin which triggers the innate immune response in plants.Transgenic Populus plants overexpressing VIP1 genes(PtVIP1 of Populus;or AtVIP1 of Arabidopsis,as positive control)were generated to investigate the role of VIP1 in vivo.The expression of poplar pathogenesis-related protein 1(PR1)genes was upregulated in transgenic-PtVIP1 or AtVIP1 poplar plants.The transgenic poplar plants overexpressing PtVIP1 or AtVIP1 also showed enhanced resistance to Brenneria salicis infection.These results suggest that the VIP1 protein accumulates in the nucleus in response to biotic stress,and that the pathogen resistance of transgenic VIP1 poplar may be associated with the induced expression of PR1 genes in response to pathogen challenge.
文摘Objective To characterize early afterdepolarizations （EADs） caused triggered activity （TA） among calsequestrin-2 （CASQ2） knock-in （CASQ2 KI） mice and its relationship with aging. Methods Electrophysiological properties of ventricular myocytes from 3- month （mo, young）, 9-mo （adult-l） and 12-too （adult-2） in wild-type （WT） and CASQ2 KI mice were investigated with patch-clamp technique. Results The incidences of EADs and TA in CASQ2 KI cardiomyocytes increased with increasing age. In contrast, WT mice cardiomyocytes showed no significant change in matched-age groups. Compared with that in 3-mo CASQ2 KI mice, the 50% repolarization of action potential （APD50） showed prolongation in both 9-mo and 12-mo ones （9.2±0.9 ms of 9-mo and 10.3 ± 1.2 ms of 12- mo vs. 5.6± 0.3 ms of 3-mo）, while the 90 % repolarization of action potential （APD90） was similar among 3 age groups. Compared with 3-mo mice, the 9-mo and 12-mo CASQ2 KI mice showed markedly reduced transient outward potassium current （Ito） densities but increased L-type calcium current （ICa-L） densities. Conlcusion This study suggested that events of EADs and TA in CASQ2 KI mice increased with increasing age, It might be associated partly with the augment of cellular calcium concentration and the prolongation of APD50 induced by decrease of Ito and increase of ICa-L in adult CASQ2 KI mice
文摘Genetic engineering of forest tree species is regarded as a strategy to reduce worldwide pressure on natural forests, to conserve genetic resources and ameliorate stress on global climate, and to meet growing demand for forest wood and timber products. Genetic engineering approaches toward the control or management of fungal pathogens, arthropod herbivores, bacterial and viral diseases, the use of pest resistance genes, and weed competitors are being studied. Although the production of transgenic trees is relatively recent and only a few species have been successfully genetically engineered in forest tree species, very useful and valuable information is available on the application of transgenic trees. Genes involved in important agricultural traits such as herbicide resistance, insect resistance, and wood quality have been isolated and have been used to genetically engineer trees. New technologies of plant molecular biology and genomics now make it possible high-efficient genetic improvement of forest trees. Genetic engineering promises to expand greatly the potential for genetic manipulation as new genes of commercial interest are discovered and utilized. Lignification is a process essential to the nature and evolution of vascular plants that is still poorly understood, even though it has been studied for more than a century. Recent studies on mutant and transgenic plants indicate that lignification may be far more flexible than previously realized. Rines with a mutation affecting the biosynthesis of the major lignin precursor, coniferyl alcohol, show a high level of an unusual subunit, dihydroconiferyl alcohol. It is also unusual as a plant polymer in that there are no plant enzymes for its degradation. These results have significant implications regarding the tradiational definition of lignin, and highlight the need for a better understanding of the lignin precursor biosynthetic pathway. In this review, we describe the progress made recently in genetic engineering of forest tree species.
基金Supported by the Hi-Tech Research and Development Program of China (863) (2001AA244060 and 2003AA244020) and National Basic Research Program of China (973) (J1999016003)
文摘A 3 125 bp cellulose synthase gene, PtoCesA1, which has a 98% identity to PtrCesA1 from Populus tremuloides, was cloned from cDNA prepared from secondary xylem of P tomentosa. Four anti-expression vectors with different fragments of PtoCesAl, named as pBIPF, pBICC1, pBIPR and pBIBR, were constructed. Some traits of transformed tobacco of pBICC1, pBIPR and pBIBR differed from wild types, such as small leaves, ＂dwarf＂ phenotype and thinner xylem and fiber cell walls than wild plants consistent with a loss of cellulose. It indicated that the growth of transgenic tobacco was restrained by the expression of anti-PtoCesA1. Transgenic tobacco was obtained and the contents of cellulose and lignin were analyzed as well as the width and length of fiber cells, and xylem thickness for both transgenic and control plants. Transformed tobacco showed a different phenotype from control plants and it implied that PtoCesA1 was essential for the cellulose biosynthesis in poplar stems.
基金supported by the National Natural Science Foundation of China(No.31270703)the Special Fund for Outstanding Talented Person of Harbin City(2012RFXXN023)100 Talents Program of The Chinese Academy of Sciences
文摘The ethylene-responsive factor family is one of the largest families of plant-specific transcription factors that are involved in plant development and stress responses. Previously, we demonstrated that the gene Th ERF1,encoding a novel ethylene-responsive factor from Tamarix hispida, negatively modulates abiotic stress tolerance. In the present study, Arabidopsis plants overexpressing Th ERF1 had decreased oxidative tolerance and increased transpirational water loss rate compared with wild-type plants, leading to sensitivity to abiotic stress. Real-time RT-PCR showed that the upstream regulator of Th ERF1,Th WRKY2, is involved in responses to different abiotic stresses. Furthermore, both Th WRKY2 and Th ERF1 shared similar expression patterns in the stems and leaves of T.hispida when exposed to salinity, drought and abscisic acid. Chromatin immunoprecipitation assays further confirmed that Th WRKY2 can directly bind to the promoter of Th ERF1 and regulate its expression. This study revealed the regulatory mechanism of Th ERF1 expression in response to abiotic stresses in T. hispida.
基金financially supported by the National Science and Technology Program of China(2013AA102704)the National Natural Science Foundation of China(J1210053)the Fundamental Research Funds for the Central Universities(2572015EA05)
文摘SQUAMOSA-promoter binding protein-like (SPL) proteins are plant-specific transcription factors and participate in different pathways, including the vegetative to reproductive transition, male sterility, biosynthesis of gibberellic acid (GA), plant morphogenesis and response to environmental stress. In this study, we generated transgenic Arabidopsis that overexpressed Betula BplSPL8 and confirmed that BplSPL8 is a transcription factor with transcriptional activation activity and is located in the nucleus. Functional analysis of BplSPL8 showed that it is involved in regulating different development processes: (1) BplSPL8 can delay flowering by reducing sensitivity to GA under short days; (2) BplSPL8 controls the number and morphogenesis of leaves, including up-rolling leaves under long days and folded leaves mediated by GA under short days; (3) BplSPL8 can promote root elongation during late development of roots and inhibit lateral root formation; (4) BplSPL8 may be involved in regulating carotenoid biosynthesis and secretion metabolism. These results show that there is a complex regulatory network for the SPL family genes that is mediated by other components and may provide a new insights for the functional research of SPL genes.
文摘With specific designed prmers. CYP2B6 and CYP1A1 cDNA were generatecl by reverse transcrlI7tion-Polymerase chain reaction(RT-PCR )technlque Performed on total RNAs isolated frorn hum1ln liver and 3-rnethylch(,lanthrene(3-Mtt)induc human amnion FL, cells. Cell llnes (CHL, 2B6 and CtHL-1A1 ) capableof expressing hunlan cytochome P 15O (CYP ) 2B6 and 1A1 were establishecl after transfection of corre-sponding eukaryotic reconlbinant expression plasmid with human CYP2ll6 and 1A1 cDNA lnserts respectlvely. These cell lines stably expressed the mRNAs and the enzymatic activltles cc)rresI’onding to ttYP2B6and CYP1A1, respectively’ Compared with Chinese hamster lung (CHL) cells, the n1icr()nucleus frecluencyin CHl,-2B6 cells is markedly lncreased when exPosed to nitrosamines,aflatoxln B, (AFB1) and cyclophos-Phamide (CPA). Thls is also in CHL-1A1 cells,when exposed to carcinogenic polycycllc aromatic hydrocar-bons.
