Suspension cell cultures of Maytenus hookeri Loos. (Celastraceae) in SH media were established from the calli induced from the leaves and young steins of M. hookeri on MS media with the supplement of 2 mg/L 2,4-D and ...Suspension cell cultures of Maytenus hookeri Loos. (Celastraceae) in SH media were established from the calli induced from the leaves and young steins of M. hookeri on MS media with the supplement of 2 mg/L 2,4-D and 0.1 mg/L KIN (kinetin). Ethyl acetate extract of the cultures showed inhibitory activities against Penicillium avellaneum UC-4376 which was sensitive to maytansinoids. Exhaustive isolation of natural products from a large scale of suspension cell cultures did not yield maytansine instead of affording nine compounds including one novel triterpenoid, named 2, 3-diacetoxyl maytenusone (1), and eight known ones including squalene (2), beta-sitosterol (3), 2', 3', 4-triacetyl-sitoindoside I (4), salaspermic acid (5), maytenonic acid (6), 2alpha-hydroxy-maytenonic acid (7), 6, 11,12-trihydroxy-8, 11, 13-abietrien-7-one (8) and 11, 12-dihydroxy-8, 11, 13-abietatrien-7-one (9) elucidated on the basis of 1D and 2D NMR data. The H-1-NMR and C-13-NMR assignments were made for 1, 5, 6 and 7, while the C-13-NMR assignments for 5 and 6 were revised. The chemical results suggested that the suspension cell cultures of M. hookeri did not produce maytansinoids under the reported experiment conditions.展开更多
The teaching objective of vocational business English is not only to improve students' English language competence, but also to develop their intercultural communication competence. Based on an analysis of the outcom...The teaching objective of vocational business English is not only to improve students' English language competence, but also to develop their intercultural communication competence. Based on an analysis of the outcome of a survey on cultivation of English majors' intercultural competence among vocational colleges in Guangxi, the paper aims at exploring the framework and cultivating modes of intercultural communication competence for business English majors in vocational colleges.展开更多
Objective The aim was to explore callus induction and plant regeneration of perennial ryegrass, as well as provide the foundation for transgenic research on perennial ryegrass.[ Methed] Mature seeds of perennial ryegr...Objective The aim was to explore callus induction and plant regeneration of perennial ryegrass, as well as provide the foundation for transgenic research on perennial ryegrass.[ Methed] Mature seeds of perennial ryegrass were used as explants to study the effects of different hormone compositions on callus induction, proliferation and plant differentiation. Result The result showed that the induction rate achieved its highest on 2,4-D of 8 mg/L combining with 6-BA of 0.025 mg/L, which was up to 56.42%. Callus were differentiated after two to three generations, the highest differentiation rate 34.14% was achieved in the medium contained MS medium with 6-BA of 2 mg/L, and the differentiation rate was obviously affected by the callus condition after proliferation. The root inducing medium, containing 0.5 mg/L NAA and MS medium with half of macroelement, gained 98% root inducing rate. Conclusien A high frequency genetic regeneration system was established.展开更多
[Objective] The aim was to analyze sugar components in fermented rice wine by ion chromatography. [Method] The optimal condition for chromatography system of sugar analysis was selected by measuring sugars in fermente...[Objective] The aim was to analyze sugar components in fermented rice wine by ion chromatography. [Method] The optimal condition for chromatography system of sugar analysis was selected by measuring sugars in fermented rice wine with ion chromatography and pulsed amperometric detection. [Result] The optimal measurement conditions were as follows: Leacheate (Leachate), consisting of NaOH and CH3COONa, was eluted by gradient concentrations, with column temperature at 35 ℃ and flow rate at 0.4 ml/min. In the condition, sugars in rice wine were ana- lyzed and the results showed that the method is featured by low detection limit, good repetition and high recovery rate. [Conclusion] The research establishes and determines the approaches and optimum conditions for sugar analysis in rice wine by ion chromatography and pulsed amperometric detection, providing references for advancement of research on quality improvement of fermented rice wine.展开更多
To understand the genetic background of root growth of rice ( Oryza sativa L.) seedlings under different water supply conditions, quantitative trait loci (QTLs) and epistatic effect on seminal root length, maximum adv...To understand the genetic background of root growth of rice ( Oryza sativa L.) seedlings under different water supply conditions, quantitative trait loci (QTLs) and epistatic effect on seminal root length, maximum adventitious root length, adventitious root number, total root dry weight and ratio of root to shoot were detected using molecular map including 103 restriction fragment length polymorphism (RFLP) markers and 104 amplified fragment length polymorphism (AFLP) markers mapped on a recombinant inbred line (RIL) population with 150 lines derived from a cross between an lowland rice IR1552 and an upland rice Azucena in both solution culture (lowland condition) and paper culture (upland condition). Six QTLs and twenty-two pairs of epistatic loci for the four parameters were detected. Three QTLs detected for maximum adventitious root length in solution culture (MARLS), total root dry weight in both solution culture and paper culture (TRDWS and TRDWP) accounted for about 20%, 23% and 13% of the total variations, respectively. Only epistatic loci were found for maximum adventitious root length and adventitious root number in paper culture (MARLP and ARNP), and for ratio of root to shoot in both paper and solution culture (R/SP and R/SS), which accounted for about 12%-61% of the total variations in the parameters, respectively. No identical QTL or epistatic loci were found for the parameters in both solution and paper culture. The results indicate that there is a different genetic system responsible to root growth of rice seedlings under lowland and upland conditions and epistasis might be the major genetic basis for MARLP, ARNP, R/SP and R/SS.展开更多
[Objective]This study was to screen out suitable genotypes and basic medium for the culture of maize mature embryos.[Method]Using mature embryos of nine maize genotypes as explants,the effects of genotypes and basic m...[Objective]This study was to screen out suitable genotypes and basic medium for the culture of maize mature embryos.[Method]Using mature embryos of nine maize genotypes as explants,the effects of genotypes and basic medium on callus induction and subculture were investigated.[Result]The genotypes performed better in callus induction and subculture were found in turn 853-35,853-209,Dan 34 and 81162.MS medium is better than N6 medium in the callus induction from maize embryos,while N6 medium is more suitable for callus subculture.[Conclusion]Our study further improved the tissue culture system in maize with mature embryos as explants.展开更多
A full habituated cell line C_ 20hi was screened from 2,4_D dependent line (C_ 20D) of Catharanthus roseus (L.) G. Don. The investigation involved the cell growth, ajmalicine production and enzyme activity related t...A full habituated cell line C_ 20hi was screened from 2,4_D dependent line (C_ 20D) of Catharanthus roseus (L.) G. Don. The investigation involved the cell growth, ajmalicine production and enzyme activity related to indole alkaloid biosynthesis in both cell lines. These results indicated that C_ 20hi cells grew faster than C_ 20D cells, and average ajmalicine content in C_ 20hi cells was 18.4 times more than that in C_ 20D when cultured in the production medium. In the growth medium, average ajmalicine content in C_ 20hi cells was 31.9 times more than that in C_ 20D cells, while the cell growth has no obvious difference. The comparison of enzyme activities in C_ 20hi and C_ 20D cells indicated that tryptophan decarboxylase (TDC), strictosidine synthase (SSS) and geraniol_10_dehydrogenase (G10H) activities have no close relation to ajmalicine accumulation, although the activities of these enzymes were higher when cells were cultured in the production medium than in the growth medium. The C_ 20hi cells are relatively stable in five years of culture.展开更多
The transcatheter aortic valve implantation (TAVI) consist an altemative treatment in patients with severe aortic stenosis. Multimodality imaging using transthoracic echocardiography (TTE) or transesophageal echoc...The transcatheter aortic valve implantation (TAVI) consist an altemative treatment in patients with severe aortic stenosis. Multimodality imaging using transthoracic echocardiography (TTE) or transesophageal echocardiography (TOE) and multislice CT (MSCT) constitute cornerstone techniques for the pre-operative management, peri-procedural guidance, follow up and recognition of possible transcatheter valve related complications. CT angiography is much more accurate regarding the total definition of aortic annulus diameter and circumferential area. Two-dimensional (2D) echocardiography, underestimates the aortic valve annulus diameter compared to 3D imaging techniques (MSCT, MRI and 3D TOE). Three-dimensional TOE imaging provides measurements of the aortic valve annulus similar to those delivered by MSCT. The pre-procedural MSCT constitutes the gold standard modality minimizing the presence of paravalvular aortic regurgitation, one of the most frequent complications. TOE/TTE and MSCT performance could predict the possibility of pacemaker implantation post-procedural. The presence of a new transient or persisting MR can be assessed well by TOE. Both TTE and TOE, consist initially the basic examination for post TAVI evaluation. In case of transcatheter heart valve failure, the MSCT could be used as additional imaging technique.展开更多
In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to fres...In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to freshwater. Differentially expressed genes were mainly assigned to the degradation of cell components, ion transportation, and ribosomal biogenesis. These find- ings indicate that the algal cells degrade its components (mainly amino acids and fatty acids) to yield excessive energy (ATP) to maintain cellular ion (mainly K+ and Ca〉) homeostasis, while the depletion of amino acids and ATP, and the reduction of ribosomes attenuate the protein translation and finally slow down the cell growth.展开更多
The influence of KH\-2PO\-4, peptone and brown sugar on \%Termitomyces fuliginosu's\% mycelium formation was studied with the application of the design of quadratic rotation general combination based on determinin...The influence of KH\-2PO\-4, peptone and brown sugar on \%Termitomyces fuliginosu's\% mycelium formation was studied with the application of the design of quadratic rotation general combination based on determining the growth curve. A quadratic regression model of biomass to the doses of the above three factors was established. The model fit well and therefore the optimum fermentation condition was obtained. Responses of biomass to the three single factors and to their interactions were discussed. Thus, the highest level of biomass, 21.1 g/L, appeared under the optimized conditions when the initial KH\-2PO\-4, peptone and brown sugar were 1 g/L, 4 g/L and 72 g/L respectively.展开更多
Background: Safflower regeneration through tissue culture has long been limited to low frequency and lack of an efficient protocol that suitable for most safflower cultivars. In past decades, researches had been carri...Background: Safflower regeneration through tissue culture has long been limited to low frequency and lack of an efficient protocol that suitable for most safflower cultivars. In past decades, researches had been carried out to investigate safflower regeneration through tissue culture and great progress had been made. Objective: To investigate factors that affect safflower regeneration through tissue culture principally. Methods: This article summarized available literatures about advancements in safflower regeneration, especially discussed factors affecting safflower tissue culture in detail. Results: Safflower regeneration was fairly hard than other congeneric plants, such as chrysanthemum. The genotype, seedling age, type of explants, medium components, plant growth regulators and other additives all had specific influences on safflower tissue culture. More deepgoing researches need to be undertaken to establish an effective safflower regeneration system.展开更多
Harmful algal blooms(HABs) have led to extensive ecological and environmental issues and huge economic losses.Various HAB control techniques have been developed,and biological methods have been paid more attention.Alg...Harmful algal blooms(HABs) have led to extensive ecological and environmental issues and huge economic losses.Various HAB control techniques have been developed,and biological methods have been paid more attention.Algicidal bacteria is a general designation for bacteria which inhibit algal growth in a direct or indirect manner,and kill or damage the algal cells.A metabolite which is strongly toxic to the dinoflagellate Alexandrium tamarense was produced by strain DH46 of the alga-lysing bacterium Alteromonas sp.The culture conditions were optimized using a single-factor test method.Factors including carbon source,nitrogen source,temperature,initial pH value,rotational speed and salinity were studied.The results showed that the cultivation of the bacteria at 28℃ and 180 r min-1with initial pH 7 and 30 salt contcentration favored both the cell growth and the lysing effect of strain DH46.The optimal medium composition for strain DH46 was determined by means of uniform design experimentation,and the most important components influencing the cell density were tryptone,yeast extract,soluble starch,NaNO3 and MgSO4.When the following culture medium was used(tryptone 14.0g,yeast extract 1.63g,soluble starch 5.0 g,NaNO3 1.6 g,MgSO4 2.3 g in 1L),the largest bacterial dry weight(7.36 g L-1) was obtained,which was an enhancement of 107% compared to the initial medium;and the algal lysis rate was as high as 98.4% which increased nearly 10% after optimization.展开更多
[Objective] Abscisic acid (ABA), a plant endogenous hormone, plays an important role in plant responses to adverse environments. This study was to explore the effects of exogenous ABA on the drought resistmlce of ap...[Objective] Abscisic acid (ABA), a plant endogenous hormone, plays an important role in plant responses to adverse environments. This study was to explore the effects of exogenous ABA on the drought resistmlce of apple rootstocks under simulated drought condition induced by polyethylene glycol (PEG). [Method] Apple (Malus baccata) seedlings were employed as test material. There were five treatments (T1-5) designed as ABA application rates at 0 (T1), 25 (T2), 50 (T3), 75 (T4) and 100 (T5) μmol/L in the hydroponic experiments. The changes of the relative leaf water content (RLWC), root activity, malondialdehyde (MDA) content, proline (Pro) content, superoxide dismutase (SOD) activity and peroxidase (POD) activity were assayed under PEG stress. All indices were analyzed by principal component analysis (PCA) to evaluate the optimal ABA concentration alleviating drought stress. [Result] The different concentration of ABA could increase Pro content and antioxidant enzyme activities, relieve the descent of RLWC and decrease MDA content. Low levels of ABA increased root activity, whereas the high concentrations (T3-T5) inhibited it. Statistical analysis based on the PCA indicated that the cumulative contribution rate of the first two principal components was raised to 96.457%, and the PCA in the T2 scored the highest. [Conclusion] The exogenous ABA could decrease the damage caused by drought stress to Malus baccata seedlings and enhance the ability of drought tolerance by increasing osmolyte content, anti- oxidative enzyme activity and reducing the level of membrane lipid peroxidation. The optimal concentration of ABA was 25 μmol/L.展开更多
Three field trials, one for establishment and two for mature phases respectively, were conducted to develop weed management strategies for cashew cultivation in Ghana. The treatments for the establishment phase consis...Three field trials, one for establishment and two for mature phases respectively, were conducted to develop weed management strategies for cashew cultivation in Ghana. The treatments for the establishment phase consisted of hoe weeding of whole plot, hoe weeding of cashew lines and slashing of inter-rows, herbicide application with glyphosate of whole plot or cashew lines with slashing of inter-rows, relay cropping of the cashew plot with sorghum and a legume and intercropping with a legume. In one trial of the mature phase, the treatments were hoe weeding of whole plot two or three times a year, high slashing of whole plot three times a year, herbicide application (glyphosate) of whole plot and ring application of herbicide (glyphosate) plus high slashing of inter-rows twice a year. In the other trial, which was carried out on farmers' fields, glyphosate (Roundup) at 2.0 l/ha was tested against manual slashing. In the study of the establishment phase, neither the girth nor height of the cashew seedlings was significantly affected by the treatments. The first year and four year cumulative cashew yields were significantly affected by treatments with the intercrops giving higher yields than the glyphosate-treated plots. Intercropping as a weed control measure was generally more costly than glyphosate application or manual weeding. In the mature trials, chemical weed control slightly improved cashew nut yield and was cheaper to apply. It is recommended to adopt chemical weed control in cashew cultivation in Ghana.展开更多
Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Exper...Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Experiments were conducted with the composition of medium components obtained by genetic algorithm, and the experimental data were used to build a BP (back propagation) neural network model. The concentrations of six medium components were used as input vectors, and the nitrite oxidization rate was used as output vector of the model. The BP neural network model was used as the objective function of genetic algorithm to find the optimum medium composition for the maximum nitrite oxidization rate. The maximum nitrite oxidization rate was 0.952 g 2 NO-2-N·(g MLSS)-1·d-1 , obtained at the genetic algorithm optimized concentration of medium components (g·L-1 ): NaCl 0.58, MgSO 4 ·7H 2 O 0.14, FeSO 4 ·7H 2 O 0.141, KH 2 PO 4 0.8485, NaNO 2 2.52, and NaHCO 3 3.613. Validation experiments suggest that the experimental results are consistent with the best result predicted by the model. A scale-up experiment shows that the nitrite degraded completely after 34 h when cultured in the optimum medium, which is 10 h less than that cultured in the initial medium.展开更多
AIM: To establish a novel coculture system for ex vivo expansion of umbilical cord blood(UCB) hematopoietic progenitors using thrombopoietin (TPO)/FIt-3 ligand (FL)-transduced human marrow-derived mesenchymal s...AIM: To establish a novel coculture system for ex vivo expansion of umbilical cord blood(UCB) hematopoietic progenitors using thrombopoietin (TPO)/FIt-3 ligand (FL)-transduced human marrow-derived mesenchymal stem cells (tfhMSCs) as feeder. METHODS: UCB CD34^+ cells were isolated and cultured using four culture systems in serum-containing or serumfree medium. Suitable aliquots of cultured cells were used to monitor cell production, clonogenic activity, and long-term culture-initiating culture (LTC-IC) output. Finally, the severe-combined immunodeficient (SCID) mouse-repopulating cell (SRC) assay was performed to confirm ability of the cultured cells to reconstitute longterm hematopoiesis. RESULTS: There were no significant differences in the number of total nudeated cells among different culture systems in serum-containing medium during 21-d culture. However, on d 14, the outputs of CD34^+ cells, CFU-C and CFU-GEMM in tfhMSCs coculture system were significantly enhanced. LTC-IC assay demonstrated that the tfhMSCs coculture system had the most powerful activity. The severe-combined immunodeficient (SCID) mouse repopulating cell (SRC) assay confirmed extensive ability of the expanded cells to reconstitute long-term hematopoiesis. Furthermore, PCR analysis demonstrated the presence of human hematopoietic cells in the bone marrow and peripheral blood cells of NOD/SCID mice.CONCLUSION: The TPO/FL-transduced hMSCs, in combination with additive cytokines, can effectively expand hematopoietic progenitors from UCB in vitro and the tfhMSCs coculture system may be a suitable system for ex vivo manipulation of primitive progenitor cells under contact culture conditions.展开更多
[Objective] Iron deficiency is one of the most important crop element deficiencies in the Loess Plateau of northwestern China. The selection for crop cultivars that are tolerant to low iron levels could be one of the ...[Objective] Iron deficiency is one of the most important crop element deficiencies in the Loess Plateau of northwestern China. The selection for crop cultivars that are tolerant to low iron levels could be one of the approaches to solving the problem and improving crop production. [Method] Three major apple root stock species (Malus prunifolia, Malus sieversii and Malus baccata) were selected to evaluate their tolerance to iron defciency in hydroponic system. A 3×2 factorial pot experiment was conducted with three replicates in a greenhouse at Gansu Agricultural University, Lanzhou, China. [Result] The SOD, POD and CAT activities in roots and stems of the 3 root stock species in Fe-defcient Hoagland solution decreased, however Malus sieversii got the less reduction and had better root architecture and growth than the other species. The aboveground biomass, plant height, chlorophyll content, total root length and lateral root number were correlated positively with iron-defciency stress tolerance. The species’ tolerance to iron-defciency from high to low was M. sieversii’s〉M. baccata’s〉M. prunifolia’s. Moreover, the improvement of some morphological features such as root length, above-ground biomass, plant height and lateral root number in apple could be conducive to breeding cultivars with tolerance to iron-defciency stress. [Conclusion] Malus sieversii had better tolerance to iron-defciency stress than the others in this study.展开更多
The successful experiences that cause Peking Female Higher Normal College (PKFHNC) to complete a relatively large scale of talents training task and become the birthplace of modern female intellectuals in early 20th...The successful experiences that cause Peking Female Higher Normal College (PKFHNC) to complete a relatively large scale of talents training task and become the birthplace of modern female intellectuals in early 20th century China in spite of disorder of social circumstance outside and regular educational system inside are as follows. First, with the endeavor of Chen Zhongfan, Dean of Chinese Department, PKFHNC gathered lots of leading scholars both from old school and new school during May Fourth Movement; second, these leading scholars' diversified academic thoughts, political ideas, and educational experiences encouraged students to think freely and critically; finally, their deep concerns about the future of China society, academic disciplines, and women's liberation and education caused all superficial changes and differences of PKFHNC to form an united spiritual power, which promoted this group of female students' development deeply.展开更多
文摘Suspension cell cultures of Maytenus hookeri Loos. (Celastraceae) in SH media were established from the calli induced from the leaves and young steins of M. hookeri on MS media with the supplement of 2 mg/L 2,4-D and 0.1 mg/L KIN (kinetin). Ethyl acetate extract of the cultures showed inhibitory activities against Penicillium avellaneum UC-4376 which was sensitive to maytansinoids. Exhaustive isolation of natural products from a large scale of suspension cell cultures did not yield maytansine instead of affording nine compounds including one novel triterpenoid, named 2, 3-diacetoxyl maytenusone (1), and eight known ones including squalene (2), beta-sitosterol (3), 2', 3', 4-triacetyl-sitoindoside I (4), salaspermic acid (5), maytenonic acid (6), 2alpha-hydroxy-maytenonic acid (7), 6, 11,12-trihydroxy-8, 11, 13-abietrien-7-one (8) and 11, 12-dihydroxy-8, 11, 13-abietatrien-7-one (9) elucidated on the basis of 1D and 2D NMR data. The H-1-NMR and C-13-NMR assignments were made for 1, 5, 6 and 7, while the C-13-NMR assignments for 5 and 6 were revised. The chemical results suggested that the suspension cell cultures of M. hookeri did not produce maytansinoids under the reported experiment conditions.
文摘The teaching objective of vocational business English is not only to improve students' English language competence, but also to develop their intercultural communication competence. Based on an analysis of the outcome of a survey on cultivation of English majors' intercultural competence among vocational colleges in Guangxi, the paper aims at exploring the framework and cultivating modes of intercultural communication competence for business English majors in vocational colleges.
基金Supported by National Natural Science Foundation of China(30471274)~~
文摘Objective The aim was to explore callus induction and plant regeneration of perennial ryegrass, as well as provide the foundation for transgenic research on perennial ryegrass.[ Methed] Mature seeds of perennial ryegrass were used as explants to study the effects of different hormone compositions on callus induction, proliferation and plant differentiation. Result The result showed that the induction rate achieved its highest on 2,4-D of 8 mg/L combining with 6-BA of 0.025 mg/L, which was up to 56.42%. Callus were differentiated after two to three generations, the highest differentiation rate 34.14% was achieved in the medium contained MS medium with 6-BA of 2 mg/L, and the differentiation rate was obviously affected by the callus condition after proliferation. The root inducing medium, containing 0.5 mg/L NAA and MS medium with half of macroelement, gained 98% root inducing rate. Conclusien A high frequency genetic regeneration system was established.
基金Supported by Changsha Key Project in Hunan Province(K1005007-21)~~
文摘[Objective] The aim was to analyze sugar components in fermented rice wine by ion chromatography. [Method] The optimal condition for chromatography system of sugar analysis was selected by measuring sugars in fermented rice wine with ion chromatography and pulsed amperometric detection. [Result] The optimal measurement conditions were as follows: Leacheate (Leachate), consisting of NaOH and CH3COONa, was eluted by gradient concentrations, with column temperature at 35 ℃ and flow rate at 0.4 ml/min. In the condition, sugars in rice wine were ana- lyzed and the results showed that the method is featured by low detection limit, good repetition and high recovery rate. [Conclusion] The research establishes and determines the approaches and optimum conditions for sugar analysis in rice wine by ion chromatography and pulsed amperometric detection, providing references for advancement of research on quality improvement of fermented rice wine.
文摘To understand the genetic background of root growth of rice ( Oryza sativa L.) seedlings under different water supply conditions, quantitative trait loci (QTLs) and epistatic effect on seminal root length, maximum adventitious root length, adventitious root number, total root dry weight and ratio of root to shoot were detected using molecular map including 103 restriction fragment length polymorphism (RFLP) markers and 104 amplified fragment length polymorphism (AFLP) markers mapped on a recombinant inbred line (RIL) population with 150 lines derived from a cross between an lowland rice IR1552 and an upland rice Azucena in both solution culture (lowland condition) and paper culture (upland condition). Six QTLs and twenty-two pairs of epistatic loci for the four parameters were detected. Three QTLs detected for maximum adventitious root length in solution culture (MARLS), total root dry weight in both solution culture and paper culture (TRDWS and TRDWP) accounted for about 20%, 23% and 13% of the total variations, respectively. Only epistatic loci were found for maximum adventitious root length and adventitious root number in paper culture (MARLP and ARNP), and for ratio of root to shoot in both paper and solution culture (R/SP and R/SS), which accounted for about 12%-61% of the total variations in the parameters, respectively. No identical QTL or epistatic loci were found for the parameters in both solution and paper culture. The results indicate that there is a different genetic system responsible to root growth of rice seedlings under lowland and upland conditions and epistasis might be the major genetic basis for MARLP, ARNP, R/SP and R/SS.
基金Supported by National Natural Science Foundation of China(31070224)National Natural Science Foundation of China(30970219)Key Project from Science and Technology Department in Jilin Province(20080203)~~
文摘[Objective]This study was to screen out suitable genotypes and basic medium for the culture of maize mature embryos.[Method]Using mature embryos of nine maize genotypes as explants,the effects of genotypes and basic medium on callus induction and subculture were investigated.[Result]The genotypes performed better in callus induction and subculture were found in turn 853-35,853-209,Dan 34 and 81162.MS medium is better than N6 medium in the callus induction from maize embryos,while N6 medium is more suitable for callus subculture.[Conclusion]Our study further improved the tissue culture system in maize with mature embryos as explants.
文摘A full habituated cell line C_ 20hi was screened from 2,4_D dependent line (C_ 20D) of Catharanthus roseus (L.) G. Don. The investigation involved the cell growth, ajmalicine production and enzyme activity related to indole alkaloid biosynthesis in both cell lines. These results indicated that C_ 20hi cells grew faster than C_ 20D cells, and average ajmalicine content in C_ 20hi cells was 18.4 times more than that in C_ 20D when cultured in the production medium. In the growth medium, average ajmalicine content in C_ 20hi cells was 31.9 times more than that in C_ 20D cells, while the cell growth has no obvious difference. The comparison of enzyme activities in C_ 20hi and C_ 20D cells indicated that tryptophan decarboxylase (TDC), strictosidine synthase (SSS) and geraniol_10_dehydrogenase (G10H) activities have no close relation to ajmalicine accumulation, although the activities of these enzymes were higher when cells were cultured in the production medium than in the growth medium. The C_ 20hi cells are relatively stable in five years of culture.
文摘The transcatheter aortic valve implantation (TAVI) consist an altemative treatment in patients with severe aortic stenosis. Multimodality imaging using transthoracic echocardiography (TTE) or transesophageal echocardiography (TOE) and multislice CT (MSCT) constitute cornerstone techniques for the pre-operative management, peri-procedural guidance, follow up and recognition of possible transcatheter valve related complications. CT angiography is much more accurate regarding the total definition of aortic annulus diameter and circumferential area. Two-dimensional (2D) echocardiography, underestimates the aortic valve annulus diameter compared to 3D imaging techniques (MSCT, MRI and 3D TOE). Three-dimensional TOE imaging provides measurements of the aortic valve annulus similar to those delivered by MSCT. The pre-procedural MSCT constitutes the gold standard modality minimizing the presence of paravalvular aortic regurgitation, one of the most frequent complications. TOE/TTE and MSCT performance could predict the possibility of pacemaker implantation post-procedural. The presence of a new transient or persisting MR can be assessed well by TOE. Both TTE and TOE, consist initially the basic examination for post TAVI evaluation. In case of transcatheter heart valve failure, the MSCT could be used as additional imaging technique.
基金financially supported by the National Natural Science Foundation of China(31270408)National High Technology Research and Development Program(863 Program)of China(2014AA022001)
文摘In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to freshwater. Differentially expressed genes were mainly assigned to the degradation of cell components, ion transportation, and ribosomal biogenesis. These find- ings indicate that the algal cells degrade its components (mainly amino acids and fatty acids) to yield excessive energy (ATP) to maintain cellular ion (mainly K+ and Ca〉) homeostasis, while the depletion of amino acids and ATP, and the reduction of ribosomes attenuate the protein translation and finally slow down the cell growth.
文摘The influence of KH\-2PO\-4, peptone and brown sugar on \%Termitomyces fuliginosu's\% mycelium formation was studied with the application of the design of quadratic rotation general combination based on determining the growth curve. A quadratic regression model of biomass to the doses of the above three factors was established. The model fit well and therefore the optimum fermentation condition was obtained. Responses of biomass to the three single factors and to their interactions were discussed. Thus, the highest level of biomass, 21.1 g/L, appeared under the optimized conditions when the initial KH\-2PO\-4, peptone and brown sugar were 1 g/L, 4 g/L and 72 g/L respectively.
基金Supported by the National Natural Science Foundation of China Granted Project(81173484)
文摘Background: Safflower regeneration through tissue culture has long been limited to low frequency and lack of an efficient protocol that suitable for most safflower cultivars. In past decades, researches had been carried out to investigate safflower regeneration through tissue culture and great progress had been made. Objective: To investigate factors that affect safflower regeneration through tissue culture principally. Methods: This article summarized available literatures about advancements in safflower regeneration, especially discussed factors affecting safflower tissue culture in detail. Results: Safflower regeneration was fairly hard than other congeneric plants, such as chrysanthemum. The genotype, seedling age, type of explants, medium components, plant growth regulators and other additives all had specific influences on safflower tissue culture. More deepgoing researches need to be undertaken to establish an effective safflower regeneration system.
基金financially supported by the National Natural Science Foundation(40930847,31070442)the Natural Science Foundation of Fujian Province(2012J01150)Public science and technology research funds projects of ocean(201305016,201305041,201305022) and MELRI1003
文摘Harmful algal blooms(HABs) have led to extensive ecological and environmental issues and huge economic losses.Various HAB control techniques have been developed,and biological methods have been paid more attention.Algicidal bacteria is a general designation for bacteria which inhibit algal growth in a direct or indirect manner,and kill or damage the algal cells.A metabolite which is strongly toxic to the dinoflagellate Alexandrium tamarense was produced by strain DH46 of the alga-lysing bacterium Alteromonas sp.The culture conditions were optimized using a single-factor test method.Factors including carbon source,nitrogen source,temperature,initial pH value,rotational speed and salinity were studied.The results showed that the cultivation of the bacteria at 28℃ and 180 r min-1with initial pH 7 and 30 salt contcentration favored both the cell growth and the lysing effect of strain DH46.The optimal medium composition for strain DH46 was determined by means of uniform design experimentation,and the most important components influencing the cell density were tryptone,yeast extract,soluble starch,NaNO3 and MgSO4.When the following culture medium was used(tryptone 14.0g,yeast extract 1.63g,soluble starch 5.0 g,NaNO3 1.6 g,MgSO4 2.3 g in 1L),the largest bacterial dry weight(7.36 g L-1) was obtained,which was an enhancement of 107% compared to the initial medium;and the algal lysis rate was as high as 98.4% which increased nearly 10% after optimization.
文摘[Objective] Abscisic acid (ABA), a plant endogenous hormone, plays an important role in plant responses to adverse environments. This study was to explore the effects of exogenous ABA on the drought resistmlce of apple rootstocks under simulated drought condition induced by polyethylene glycol (PEG). [Method] Apple (Malus baccata) seedlings were employed as test material. There were five treatments (T1-5) designed as ABA application rates at 0 (T1), 25 (T2), 50 (T3), 75 (T4) and 100 (T5) μmol/L in the hydroponic experiments. The changes of the relative leaf water content (RLWC), root activity, malondialdehyde (MDA) content, proline (Pro) content, superoxide dismutase (SOD) activity and peroxidase (POD) activity were assayed under PEG stress. All indices were analyzed by principal component analysis (PCA) to evaluate the optimal ABA concentration alleviating drought stress. [Result] The different concentration of ABA could increase Pro content and antioxidant enzyme activities, relieve the descent of RLWC and decrease MDA content. Low levels of ABA increased root activity, whereas the high concentrations (T3-T5) inhibited it. Statistical analysis based on the PCA indicated that the cumulative contribution rate of the first two principal components was raised to 96.457%, and the PCA in the T2 scored the highest. [Conclusion] The exogenous ABA could decrease the damage caused by drought stress to Malus baccata seedlings and enhance the ability of drought tolerance by increasing osmolyte content, anti- oxidative enzyme activity and reducing the level of membrane lipid peroxidation. The optimal concentration of ABA was 25 μmol/L.
文摘Three field trials, one for establishment and two for mature phases respectively, were conducted to develop weed management strategies for cashew cultivation in Ghana. The treatments for the establishment phase consisted of hoe weeding of whole plot, hoe weeding of cashew lines and slashing of inter-rows, herbicide application with glyphosate of whole plot or cashew lines with slashing of inter-rows, relay cropping of the cashew plot with sorghum and a legume and intercropping with a legume. In one trial of the mature phase, the treatments were hoe weeding of whole plot two or three times a year, high slashing of whole plot three times a year, herbicide application (glyphosate) of whole plot and ring application of herbicide (glyphosate) plus high slashing of inter-rows twice a year. In the other trial, which was carried out on farmers' fields, glyphosate (Roundup) at 2.0 l/ha was tested against manual slashing. In the study of the establishment phase, neither the girth nor height of the cashew seedlings was significantly affected by the treatments. The first year and four year cumulative cashew yields were significantly affected by treatments with the intercrops giving higher yields than the glyphosate-treated plots. Intercropping as a weed control measure was generally more costly than glyphosate application or manual weeding. In the mature trials, chemical weed control slightly improved cashew nut yield and was cheaper to apply. It is recommended to adopt chemical weed control in cashew cultivation in Ghana.
基金Supported by the National Natural Science Foundation of China (21076090)
文摘Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Experiments were conducted with the composition of medium components obtained by genetic algorithm, and the experimental data were used to build a BP (back propagation) neural network model. The concentrations of six medium components were used as input vectors, and the nitrite oxidization rate was used as output vector of the model. The BP neural network model was used as the objective function of genetic algorithm to find the optimum medium composition for the maximum nitrite oxidization rate. The maximum nitrite oxidization rate was 0.952 g 2 NO-2-N·(g MLSS)-1·d-1 , obtained at the genetic algorithm optimized concentration of medium components (g·L-1 ): NaCl 0.58, MgSO 4 ·7H 2 O 0.14, FeSO 4 ·7H 2 O 0.141, KH 2 PO 4 0.8485, NaNO 2 2.52, and NaHCO 3 3.613. Validation experiments suggest that the experimental results are consistent with the best result predicted by the model. A scale-up experiment shows that the nitrite degraded completely after 34 h when cultured in the optimum medium, which is 10 h less than that cultured in the initial medium.
基金Supported by the grants of NIH-Heart,Lung & Blood,No.IR014L70593-01 and Zhejiang Scientific Foundation,No.2003C23015
文摘AIM: To establish a novel coculture system for ex vivo expansion of umbilical cord blood(UCB) hematopoietic progenitors using thrombopoietin (TPO)/FIt-3 ligand (FL)-transduced human marrow-derived mesenchymal stem cells (tfhMSCs) as feeder. METHODS: UCB CD34^+ cells were isolated and cultured using four culture systems in serum-containing or serumfree medium. Suitable aliquots of cultured cells were used to monitor cell production, clonogenic activity, and long-term culture-initiating culture (LTC-IC) output. Finally, the severe-combined immunodeficient (SCID) mouse-repopulating cell (SRC) assay was performed to confirm ability of the cultured cells to reconstitute longterm hematopoiesis. RESULTS: There were no significant differences in the number of total nudeated cells among different culture systems in serum-containing medium during 21-d culture. However, on d 14, the outputs of CD34^+ cells, CFU-C and CFU-GEMM in tfhMSCs coculture system were significantly enhanced. LTC-IC assay demonstrated that the tfhMSCs coculture system had the most powerful activity. The severe-combined immunodeficient (SCID) mouse repopulating cell (SRC) assay confirmed extensive ability of the expanded cells to reconstitute long-term hematopoiesis. Furthermore, PCR analysis demonstrated the presence of human hematopoietic cells in the bone marrow and peripheral blood cells of NOD/SCID mice.CONCLUSION: The TPO/FL-transduced hMSCs, in combination with additive cytokines, can effectively expand hematopoietic progenitors from UCB in vitro and the tfhMSCs coculture system may be a suitable system for ex vivo manipulation of primitive progenitor cells under contact culture conditions.
基金Supported by University Research Project of Education Dpartment(2018A-035)~~
文摘[Objective] Iron deficiency is one of the most important crop element deficiencies in the Loess Plateau of northwestern China. The selection for crop cultivars that are tolerant to low iron levels could be one of the approaches to solving the problem and improving crop production. [Method] Three major apple root stock species (Malus prunifolia, Malus sieversii and Malus baccata) were selected to evaluate their tolerance to iron defciency in hydroponic system. A 3×2 factorial pot experiment was conducted with three replicates in a greenhouse at Gansu Agricultural University, Lanzhou, China. [Result] The SOD, POD and CAT activities in roots and stems of the 3 root stock species in Fe-defcient Hoagland solution decreased, however Malus sieversii got the less reduction and had better root architecture and growth than the other species. The aboveground biomass, plant height, chlorophyll content, total root length and lateral root number were correlated positively with iron-defciency stress tolerance. The species’ tolerance to iron-defciency from high to low was M. sieversii’s〉M. baccata’s〉M. prunifolia’s. Moreover, the improvement of some morphological features such as root length, above-ground biomass, plant height and lateral root number in apple could be conducive to breeding cultivars with tolerance to iron-defciency stress. [Conclusion] Malus sieversii had better tolerance to iron-defciency stress than the others in this study.
基金Project funded by China Postdoctoral Science Foundation (2016M590648).
文摘The successful experiences that cause Peking Female Higher Normal College (PKFHNC) to complete a relatively large scale of talents training task and become the birthplace of modern female intellectuals in early 20th century China in spite of disorder of social circumstance outside and regular educational system inside are as follows. First, with the endeavor of Chen Zhongfan, Dean of Chinese Department, PKFHNC gathered lots of leading scholars both from old school and new school during May Fourth Movement; second, these leading scholars' diversified academic thoughts, political ideas, and educational experiences encouraged students to think freely and critically; finally, their deep concerns about the future of China society, academic disciplines, and women's liberation and education caused all superficial changes and differences of PKFHNC to form an united spiritual power, which promoted this group of female students' development deeply.