Seed morphology,germination and seedlings growth of Acacia auriculiformis were studied.The experiment was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds ...Seed morphology,germination and seedlings growth of Acacia auriculiformis were studied.The experiment was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of the species were collected from healthy trees of road side plantation from different areas of Khulna District,Bangladesh and treated with five pre-sowing treatments（control,immersion in cold water,immersion in hot water,scarification with sand paper and immersion in concentrated H2SO4）.The average length,breadth and thickness were found to be（0.58±0.017） cm,（0.44±0.007） cm and（0.20±0.089） cm,respectively.Germination was conducted in polybags with a mixture of top soil,coconut husk,coarse sand,and fine sand in a ratio of 3：4：1：1.Results reveal that pre-sowing treatments influences the germination rates of seeds that significantly increase the percentage germination compared with those in control（43%） and cold water treatment（52%）.The highest germination success rate was found 83% in hot water treatment followed by 78% in scarification with sand paper,and 75% with immersion in H2SO4.Germination started from 7 to 12 days and completed between 28 and 35 days period in all treatments.ANOVA showed the significant difference（p0.05） among the treatments in seed germination,but no significant difference among treatment with regard to starting day,closing day and total germination period.In case of height and diameter growth,seedlings originated from the seeds with hot water treatment shows significantly higher in wet season（from May to July）.Hot water treatment can be recommended on seed germination of the species in rural Bangladesh.展开更多
Albizia saman （Jacq.） F. Muell. commonly known as rain tree seeds were treated with five pre-sowing treatments to study the effect of pre-sowing treatments on germination and initial seedling development in the nurs...Albizia saman （Jacq.） F. Muell. commonly known as rain tree seeds were treated with five pre-sowing treatments to study the effect of pre-sowing treatments on germination and initial seedling development in the nursery.The experiment was established in the nursery of the Institute of Forestry and Environmental Sciences.University of Chittagong, Chittagong, Bangladesh. Results revealed that Nail clipping in one side of the seed （at the distal end of the seed） （T4） provides the highest （50%） seed germination. The second highest germination （42%） was obtained for the seeds treated with immersion in cold water for 24 h （T1）. Germination was completely inhibited when the seeds immersed in boiled water for 30 s followed in cold water soaking for 24 h. Other germination parameter and initial morphological growth and biomass production of the seedlings was also higher for the treatments T4and Ti in comparison to the control （Ta）treatment. Pre-sowing treatments of T4 e.g. Nail clipping in one side of the seed （at the distal end of the seed） and T1 （Seeds immersed in cold water for 24 h） may be recommended for maximum germination and initial vigorous seedlings growth of Albizia sarnan in the nursery.展开更多
Interferon-gamma （IFN-γ） is a major proinflammatory effector and regulatory cytokine produced by activated T cells and NK cells. IFN-γ has been shown to play pivotal roles in fundamental immunological processes su...Interferon-gamma （IFN-γ） is a major proinflammatory effector and regulatory cytokine produced by activated T cells and NK cells. IFN-γ has been shown to play pivotal roles in fundamental immunological processes such as inflammatory reactions, cell-mediated immunity and autoimmunity. A variety of human disorders have now been linked to irregular IFN-γ expression. In order to achieve proper IFN-γ-mediated immunological effects, IFN-γ expression in T cells is subject to both positive and negative regulation. In this study, we report for the first time the negative regulation of IFN-γ expression by Prospero-related Homeobox （Proxl）. In Jurkat T cells and primary human CD4＋ T cells, Proxl expression decreases quickly upon T cell activation, concurrent with a dramatic increase in IFN-γ expression. Reporter analysis and chromatin immunoprecipitation （CHIP） revealed that Proxl associates with and inhibits the transcription activity of IFN-γ promoter in activated Jurkat T cells. Co-immunoprecipitation and GST pull-down assay demonstrated a direct binding between Proxl and the nuclear receptor peroxisome proliferator-activated receptor gamma （PPARγ）, which is also an IFN-γ repressor in T cells. By introducing deletions and mutations into Proxl, we show that the repression of IFN-γ promoter by Proxl is largely dependent upon the physical interaction between Proxl and PPARγ. Furthermore, PPARγ antagonist treatment removes Proxl from IFN-γ promoter and attenuates repression of IFN-γ expression by Proxl. These findings establish Proxl as a new negative regulator of IFN-γ expression in T cells and will aid in the understanding of IFN-γ transcription regulation mechanisms.展开更多
LSD1 （KDM1 under the new nomenclature） was the first identified lysine-specific histone demethylase belonging to the flavin-dependent amine oxidase family. Here, we report that AOF1 （KDM1B under the new nomenclatur...LSD1 （KDM1 under the new nomenclature） was the first identified lysine-specific histone demethylase belonging to the flavin-dependent amine oxidase family. Here, we report that AOF1 （KDM1B under the new nomenclature）, a mammalian protein related to LSD1, also possesses histone demethylase activity with specificity for H3K4mel and H3K4me2. Like LSD1, the highly conserved SWIRM domain is required for its enzymatic activity. However, AOF1 differs from LSD1 in several aspects. First, AOF1 does not appear to form stable protein complexes containing histone deacetylases. Second, AOF1 is found to localize to chromosomes during the mitotic phase of the cell cycle, whereas LSD1 does not. Third, AOF1 represses transcription when tethered to DNA and this repression activity is independent of its demethylase activity. Structural and functional analyses identified its unique N-terminal Zf-CW domain as essential for the demethylase activity-independent repression function. Collectively, our study identifies AOF1 as the second histone demethylase in the family of flavin-dependent amine oxidases and reveals a demethylase-independent repression function of AOF1.展开更多
A germination experiment of pre-treated seeds of Melia azedarach was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of Melia azedarach were collected fro...A germination experiment of pre-treated seeds of Melia azedarach was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of Melia azedarach were collected from healthy trees of National Botanical Garden,Bangladesh and were treated with five pre-sowing treatments（control,immersion in cold water,immersion in hot water,scarification with sand paper,and immersion in concentrated H2SO4） on seed germination.Results revealed that the germination rates of pre-sowing treated seeds were significantly increased compared to those in control,except for cold water treatment.The highest germination success（80%） was found in scarification with sand paper,followed by 74% and 69% in immersion in H2SO4 and hot water treatment,respectively.Germination started on 8-11 days and completed on 20-21 days of the germination period in all cases.Analysis of variance showed the significance difference in germination success among the treatments but no significance difference in germination period among the treatment.Hot water treatment may be recommended on seed germination of the species in rural Bangladesh.展开更多
Three pod lengths （ 10 cm, 10–20 cm and 20 cm） and 13 pre-sowing treatments were considered with four dates of collection （9 February, 19 February, 1 March and 11 March） to investigate their effect on germination...Three pod lengths （ 10 cm, 10–20 cm and 20 cm） and 13 pre-sowing treatments were considered with four dates of collection （9 February, 19 February, 1 March and 11 March） to investigate their effect on germination rate and growth of seedlings of Albizia lebbeck （L.） Benth. at Pundibari, West Bengal, India. The best time of pod collection was on 19 February as the germination rate of the seeds collected on this date was 92.5% without requiring any pre-sowing treatments. This clearly indicated that the seeds collected on 19 February were non-dormant, viable and physiologically mature. Significantly better seedling growth was also obtained when the seeds were sown on 19 February which was extracted from pods of length 10-20 cm. Application of thio-urea as a pre-treatment did not significantly enhanced seed germination rate, but its application in lower concentration （100 μL·L-1） resulted in better seedling growth and development.展开更多
Objective To study the regulatory roles of SIRT1 on EZH2 expression and the further ef-fects on EZH2's repression of target gene expression. Methods The stable SIRT1 RNAi and Control RNAi HeLa cells were establish...Objective To study the regulatory roles of SIRT1 on EZH2 expression and the further ef-fects on EZH2's repression of target gene expression. Methods The stable SIRT1 RNAi and Control RNAi HeLa cells were established by in-fection with retroviruses expressing shSIRT1 and shLuc respectively followed by puromycin selection. EZH2 protein level was detected by Western blot in either whole cell lysate or the fractional cell extract. Reverse transcription-polymerase chain reaction was performed to detect the mRNA level of EZH2. Cycloheximide was used to treat SIRT1 RNAi and Control RNAi cells for protein stability assay. Chromatin immunoprecipitation (ChIP) assay was applied to measure enrichment of SIRT1, EZH2, and trimethylated H3K27 (H3K27me3) at SATB1 promoter in SIRT1 RNAi and Control RNAi cells. Results Western blot results showed that EZH2 protein level increased upon SIRT1 de-pletion. Fractional extraction results showed unchanged cytoplasmic fraction and increased chromatin fraction of EZH2 protein in SIRT1 RNAi cells. The mRNA level of EZH2 was not affected by knockdown of SIRT1. SIRT1 recruitment was not detected at the promoter region of EZH2 gene locus. The protein stability assay showed that the protein stability of EZH2 increases upon SIRT1 knockdown. Upon SIRT1 depletion, EZH2 and H3K27me3 recruitment at SATB1 promoter increases and the mRNA level of SATB1 decreases. Conclusions Depletion of SIRT1 increases the protein stability of EZH2. The regulation of EZH2 protein level by SIRT1 affects the repressive effects of EZH2 on the target gene expres-sion.展开更多
Due to high cost and relatively low efficiency of cellulase enzymes used for the saccharification of pretreated lignocelluloses, the improvement of cellulase secreting microorganisms is of vital importance. Trichoderm...Due to high cost and relatively low efficiency of cellulase enzymes used for the saccharification of pretreated lignocelluloses, the improvement of cellulase secreting microorganisms is of vital importance. Trichoderma reesei QM 6a, an excellent source of cellulase was selected in the late 1960’s. at Natick Laboratories by its performance on pure cellulose (Solka Floc, Avicel) . QM 6a is the wild parent strain of best existing hypercellulolytic mutants such as Rut C30, VTT-D-80133, L27, CL-847 and others. Utilization of cheaper carbon sources (e.g., pretreated wood or straw) both in enzyme production and in hydrolysis necessitates to investigate fungal species other than T.reesei. A screening program was initiated to test 150 wild-type Trichoderma strains in shake flask for cellulase production on SO 2-impregnated and steam pretreated spruce and willow, candidate substrates for bioalcohol program in Sweden. Filter paper activity (FPA) method was used to determine the overall cellulase activity. Strain TUB F-1505 was selected as promising candidate for mutagenesis. This wild strain was isolated from a tropical rain forest area near Manaus, Brazil. Isolate F-1505 was subjected to NTG-mutation to select catabolite (glucose, glycerol) resistant mutants. A Petri plate clearing assay using Walseth cellulose, glycerol or glucose and Triton X100 (colony size inhibitor) was applied for pre-screening of the colonies. Over 6000 colonies were evaluated. Best colonies were tested in shake flask fermentation on pretreated spruce and willow as carbon sources. Mutants producing higher levels of cellulase (FPA) were further mutated by either NTG or UV-light. At least 4 mutants were obtained and freeze-dried exhibiting equivalent or higher cellulase production as compared to Trichoderma reesei Rut C30.展开更多
As a genre that expressed women＇s dark protests, fantasies and the fear, female Gothic was not theorized until the late 1960s, and before its theorization, this convention was adopted by many women writers in their w...As a genre that expressed women＇s dark protests, fantasies and the fear, female Gothic was not theorized until the late 1960s, and before its theorization, this convention was adopted by many women writers in their works. Charlotte Perkins Gilman＇s The yellow wallpaper is one of the many examples. As the epitome of female gothic, The yellow wallpaper utilized the female gothic conventions--the grotesque symbol of yellow wallpaper, the hysteric narrative format and the archetype image of madwoman, to express women＇s status of her time--their repression, rebellion and quest for the ＂true self＂.展开更多
This paper carries out empirical analysis of the ration behavior of rural credit cooperatives in less developed regions in providing loan services to rural households. It also inspects the interaction between rural ho...This paper carries out empirical analysis of the ration behavior of rural credit cooperatives in less developed regions in providing loan services to rural households. It also inspects the interaction between rural households＇ demand for credit and the loan supply from rural credit cooperatives with simultaneous discrete model. The performance of supporting agriculture through a new round reform of rural credit cooperatives is doubtable in this sample region.展开更多
Increasing density is one of the important factors for producing high quality powder metallurgy （PM） parts, which has beneficial effect on mechanical properties. One of the common techniques for achieving this goal ...Increasing density is one of the important factors for producing high quality powder metallurgy （PM） parts, which has beneficial effect on mechanical properties. One of the common techniques for achieving this goal is double compacting, which seems to be a potentially attractive method in PM route, also for Cr-Mo alloyed-steels. The objective of this research was to investigate the effect of first compacting pressure and intermediate annealing temperature on attaining higher densities and minimum interconnected porosity for Cr-Mo pre-alloyed steel. The effect of mentioned parameters was studied by measuring density, transverse rupture strength and macrohardness of repressed samples. The results show that for each first compacting pressure, the density range of repressed samples increases with the increasing annealing temperature up to a certain limit, due to C dissolution which causes free porosity and further densifieation. Annealing temperatures higher than optimum one should be avoided, since too much carbon dissolution results in harder and less deformable compacts. On the other hand, with regard to repressed density and other resulted properties, the amount of first compacting pressure offers considerable advantage in obtaining higher level of density and consequently improved mechanical properties.展开更多
Polycomb repressive complex 2(PRC2)contributes to catalyze the methylation of histone H3 at lysine 27 and plays vital roles in transcriptional silencing and growth development in various organisms.In Magnaporthe oryza...Polycomb repressive complex 2(PRC2)contributes to catalyze the methylation of histone H3 at lysine 27 and plays vital roles in transcriptional silencing and growth development in various organisms.In Magnaporthe oryzae,histone H3K27 is found to associate with altered transcription of in planta induced genes.However,it is still unknown whether and how H3K27me3 modification is involved in pathogenicity to rice and stress response.In this study,we found that core subunits of PRC2,Kmt6-Suz12-Eed,were required for fungal pathogenicity to rice in M.oryzae.Kmt6-Suz12-Eed localized in the nuclei and was necessary for the establishment of H3K27me3 modification.With ChIP-seq analysis,9.0%of genome regions enriched with H3K27me3 occupancy,which corresponded to 1033 genes in M.oryzae.Furthermore,deletion of Kmt6,Suz12 or Eed altered genome-wide transcriptional expression,while the de-repression genes in theΔkmt6 strain were highly associated with H3K27me3 occupancy.Notably,plenty of genes which encode effectors and secreted enzymes,secondary metabolite synthesis genes,and cell wall stress-responsive genes were directly occupied with H3K27me3 modification and de-repression in theΔkmt6 strain.These results elaborately explained how PRC2 was required for pathogenicity,which is closely related to effector modulated host immunity and host environment adaption.展开更多
Rice grain size is an important trait that affects rice yield and quality, and thus the identification of genes related to grain size is of great significance for improving rice yield and quality. Many genes related t...Rice grain size is an important trait that affects rice yield and quality, and thus the identification of genes related to grain size is of great significance for improving rice yield and quality. Many genes related to grain size, such as DEP1(Huang et al., 2009),GW5(Liu et al., 2017).展开更多
The rice false smut disease, caused by Ustilaginoidea virens, has emerged as a significantglobal threat to rice production. The mechanism of carbon catabolite repression plays a crucial role in theefficient utilizatio...The rice false smut disease, caused by Ustilaginoidea virens, has emerged as a significantglobal threat to rice production. The mechanism of carbon catabolite repression plays a crucial role in theefficient utilization of carbon nutrients and enzyme regulation in the presence of complex nutritionalconditions. Although significant progress has been made in understanding carbon catabolite repression infungi such as Aspergillus nidulans and Magnaporthe oryzae, its role in U. virens remains unclear. Toaddress this knowledge gap, we identified UvCreA, a pivotal component of carbon catabolite repression,in U. virens. Our investigation revealed that UvCreA localized to the nucleus. Deletion of UvCreA resultedin decreased growth and pathogenicity in U. virens. Through RNA-seq analysis, it was found that theknockout of UvCreA led to the up-regulation of 514 genes and down-regulation of 640 genes. Moreover,UvCreA was found to be involved in the transcriptional regulation of pathogenic genes and genesassociated with carbon metabolism in U. virens. In summary, our findings indicated that UvCreA isimportant in fungal development, virulence, and the utilization of carbon sources through transcriptionalregulation, thus making it a critical element of carbon catabolite repression.展开更多
Studies have provided indirect evidence that cellulolytic activity of some anaerobic bacteria is repressed by carbohydrates, such as glucose. This effect is known as carbon catabolite repression （CCR）. Previous work...Studies have provided indirect evidence that cellulolytic activity of some anaerobic bacteria is repressed by carbohydrates, such as glucose. This effect is known as carbon catabolite repression （CCR）. Previous work has found that cellulolytic activity of Clostridium cellulovorans and Eubacterium cellulosolvens are regulated. Many cellulolytic systems of these organisms are expressed only in the presence of cellulose or cellobiose （the disaccharide of cellulose）. Some of these cellulose-induced systems also appear subject to CCR when more soluble substrates, such as glucose, are also available. To determine if such repression directly effects cellulolytic activity of C. cellulovorans and E. cellulosolvens, these organisms were cultivated in media containing a glucose analog. We then measured the ability of low levels of analog to inhibit growth of the organisms when cellobiose or cellulose were the energy substrates. Our results found that growth of both C. cellulovorans and E. cellulosolvens in cellobiose-containing medium are strongly inhibited by glucose analogs. In addition, both organisms exhibited delayed and slower growth in cellulose-containing medium when a glucose analog was added. These results provide direct demonstration that these cellulolytic bacteria are subject to CCR. This repression of cellulolysis may affect both of these organisms＇ ability to serve as industrial platforms for biomass degradation, and may interfere with the contribution of E. cellulosolvens toward animal digestion of cellulose. These results were also in sharp contrast to what has been reported regarding CCR activity in Clostridium cellulolyticum, which actively expresses cellulases in the presence of low levels of glucose.展开更多
The influence of high temperature repressing treatment on the segregation of phosphorus in the 93W alloy was carefully investigated by means of Auger electron spectroscope,EPMA, TEM and SEM.The segregation of phosphor...The influence of high temperature repressing treatment on the segregation of phosphorus in the 93W alloy was carefully investigated by means of Auger electron spectroscope,EPMA, TEM and SEM.The segregation of phosphorus has been observed at the tungsten-tungsten grain boundaries,particularly at the tungsten-matrix interphases when the specimens were kept at the temperature in the range of 1200—1500℃ ,followed by furnace cooling.However, no segregation of phosphorus was observed at the interfaces after the specimens were re- pressed at the range of temperature,followed by furnace cooling.After investigation,the dis- locations in the matrix phase of as-repressed specimens directly influenced the phosphorus segregation to the interfaces.After annealing,the mechanical properties were reduced because of the phosphorus segregation at the interface boundaries.展开更多
Aiming at the corrosion issue of oil extraction equipments caused by sulfate-reducing bacteria （SRB） reproducing in oil field affusion system, we studied the dominant strains in the SRB community and the impact of f...Aiming at the corrosion issue of oil extraction equipments caused by sulfate-reducing bacteria （SRB） reproducing in oil field affusion system, we studied the dominant strains in the SRB community and the impact of four ecological factors on the growth of the dominant strains：temperature, pH, mineralization degree and concentration of PAM （Polyacrylamine）. The feasibility of repressing the growth of SRB by changing ecological factors was also discussed. The results indicate that Desutfobacter （one genus of SRB） is the preponderant strains of the system, and the order of the effect of four ecological factors is pH 〉 temperature 〉 the concentrations of PAM 〉 mineralization degree. The optimal pH for the highest growth rate of SRB is 8.0. No growth of SRB was observed when pH 〈 4 or pH 〉 12. The optimal temperature for the growth of SRB is 40 ℃ and the ecological amplitude is 20 -50 ℃. The appropriate concentration values of PAM is 400 -800 mg/L, beyond of which the multiplication rate and growth quantity 6f cell decrease obviously. The effect of mineralization degree of SO4^2- , HCO^3- and Na^＋ on the growth of SRB has reached an extremely remarkable level, and the change of three ions＇ concentration in water obviously effects SRB： The optimum values on the main ions in the system are Cl- of 200mg/L, HCO^3- of 900 mg/L,SO4^2- of 400 mg/L, Mg^2＋ of 60 mg/L and Na^＋ of 900 mg/L. Our results indicate that it is possible to repress the growth of SRB by changing the ecological factors in nil field affusion system.展开更多
文摘Seed morphology,germination and seedlings growth of Acacia auriculiformis were studied.The experiment was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of the species were collected from healthy trees of road side plantation from different areas of Khulna District,Bangladesh and treated with five pre-sowing treatments（control,immersion in cold water,immersion in hot water,scarification with sand paper and immersion in concentrated H2SO4）.The average length,breadth and thickness were found to be（0.58±0.017） cm,（0.44±0.007） cm and（0.20±0.089） cm,respectively.Germination was conducted in polybags with a mixture of top soil,coconut husk,coarse sand,and fine sand in a ratio of 3：4：1：1.Results reveal that pre-sowing treatments influences the germination rates of seeds that significantly increase the percentage germination compared with those in control（43%） and cold water treatment（52%）.The highest germination success rate was found 83% in hot water treatment followed by 78% in scarification with sand paper,and 75% with immersion in H2SO4.Germination started from 7 to 12 days and completed between 28 and 35 days period in all treatments.ANOVA showed the significant difference（p0.05） among the treatments in seed germination,but no significant difference among treatment with regard to starting day,closing day and total germination period.In case of height and diameter growth,seedlings originated from the seeds with hot water treatment shows significantly higher in wet season（from May to July）.Hot water treatment can be recommended on seed germination of the species in rural Bangladesh.
文摘Albizia saman （Jacq.） F. Muell. commonly known as rain tree seeds were treated with five pre-sowing treatments to study the effect of pre-sowing treatments on germination and initial seedling development in the nursery.The experiment was established in the nursery of the Institute of Forestry and Environmental Sciences.University of Chittagong, Chittagong, Bangladesh. Results revealed that Nail clipping in one side of the seed （at the distal end of the seed） （T4） provides the highest （50%） seed germination. The second highest germination （42%） was obtained for the seeds treated with immersion in cold water for 24 h （T1）. Germination was completely inhibited when the seeds immersed in boiled water for 30 s followed in cold water soaking for 24 h. Other germination parameter and initial morphological growth and biomass production of the seedlings was also higher for the treatments T4and Ti in comparison to the control （Ta）treatment. Pre-sowing treatments of T4 e.g. Nail clipping in one side of the seed （at the distal end of the seed） and T1 （Seeds immersed in cold water for 24 h） may be recommended for maximum germination and initial vigorous seedlings growth of Albizia sarnan in the nursery.
文摘Interferon-gamma （IFN-γ） is a major proinflammatory effector and regulatory cytokine produced by activated T cells and NK cells. IFN-γ has been shown to play pivotal roles in fundamental immunological processes such as inflammatory reactions, cell-mediated immunity and autoimmunity. A variety of human disorders have now been linked to irregular IFN-γ expression. In order to achieve proper IFN-γ-mediated immunological effects, IFN-γ expression in T cells is subject to both positive and negative regulation. In this study, we report for the first time the negative regulation of IFN-γ expression by Prospero-related Homeobox （Proxl）. In Jurkat T cells and primary human CD4＋ T cells, Proxl expression decreases quickly upon T cell activation, concurrent with a dramatic increase in IFN-γ expression. Reporter analysis and chromatin immunoprecipitation （CHIP） revealed that Proxl associates with and inhibits the transcription activity of IFN-γ promoter in activated Jurkat T cells. Co-immunoprecipitation and GST pull-down assay demonstrated a direct binding between Proxl and the nuclear receptor peroxisome proliferator-activated receptor gamma （PPARγ）, which is also an IFN-γ repressor in T cells. By introducing deletions and mutations into Proxl, we show that the repression of IFN-γ promoter by Proxl is largely dependent upon the physical interaction between Proxl and PPARγ. Furthermore, PPARγ antagonist treatment removes Proxl from IFN-γ promoter and attenuates repression of IFN-γ expression by Proxl. These findings establish Proxl as a new negative regulator of IFN-γ expression in T cells and will aid in the understanding of IFN-γ transcription regulation mechanisms.
基金We thank Dr Ramin Shiekhattar （Wistar Institute, USA） for the baculoviruses expressing Flag-LSD1 and Drs Jianguo Song and Degui Chen （Shanghai Institute of Biochemistry and Cell Biol- ogy, China） for anti-HDAC1 antibody and H3K36me2 antibody, respectively. This study was partially supported by grants from the National Natural Science Foundation of China （90919025, 30871381）, the Ministry of Science and Technology of China （2009CB918402, 2009CB825601） and the Research Platform for Cell Signaling Networks from the Science and Technology Com- mission of Shanghai Municipality （06DZ22923）.
文摘LSD1 （KDM1 under the new nomenclature） was the first identified lysine-specific histone demethylase belonging to the flavin-dependent amine oxidase family. Here, we report that AOF1 （KDM1B under the new nomenclature）, a mammalian protein related to LSD1, also possesses histone demethylase activity with specificity for H3K4mel and H3K4me2. Like LSD1, the highly conserved SWIRM domain is required for its enzymatic activity. However, AOF1 differs from LSD1 in several aspects. First, AOF1 does not appear to form stable protein complexes containing histone deacetylases. Second, AOF1 is found to localize to chromosomes during the mitotic phase of the cell cycle, whereas LSD1 does not. Third, AOF1 represses transcription when tethered to DNA and this repression activity is independent of its demethylase activity. Structural and functional analyses identified its unique N-terminal Zf-CW domain as essential for the demethylase activity-independent repression function. Collectively, our study identifies AOF1 as the second histone demethylase in the family of flavin-dependent amine oxidases and reveals a demethylase-independent repression function of AOF1.
文摘A germination experiment of pre-treated seeds of Melia azedarach was conducted in the nursery of Forestry and Wood Technology Discipline,Khulna University,Bangladesh.Matured seeds of Melia azedarach were collected from healthy trees of National Botanical Garden,Bangladesh and were treated with five pre-sowing treatments（control,immersion in cold water,immersion in hot water,scarification with sand paper,and immersion in concentrated H2SO4） on seed germination.Results revealed that the germination rates of pre-sowing treated seeds were significantly increased compared to those in control,except for cold water treatment.The highest germination success（80%） was found in scarification with sand paper,followed by 74% and 69% in immersion in H2SO4 and hot water treatment,respectively.Germination started on 8-11 days and completed on 20-21 days of the germination period in all cases.Analysis of variance showed the significance difference in germination success among the treatments but no significance difference in germination period among the treatment.Hot water treatment may be recommended on seed germination of the species in rural Bangladesh.
文摘Three pod lengths （ 10 cm, 10–20 cm and 20 cm） and 13 pre-sowing treatments were considered with four dates of collection （9 February, 19 February, 1 March and 11 March） to investigate their effect on germination rate and growth of seedlings of Albizia lebbeck （L.） Benth. at Pundibari, West Bengal, India. The best time of pod collection was on 19 February as the germination rate of the seeds collected on this date was 92.5% without requiring any pre-sowing treatments. This clearly indicated that the seeds collected on 19 February were non-dormant, viable and physiologically mature. Significantly better seedling growth was also obtained when the seeds were sown on 19 February which was extracted from pods of length 10-20 cm. Application of thio-urea as a pre-treatment did not significantly enhanced seed germination rate, but its application in lower concentration （100 μL·L-1） resulted in better seedling growth and development.
基金Supported by National Natural Science Foundation of China (30721063)National Basic Research Program of China (973 Program) (2005CB522402, 2006CB910403)+1 种基金National Laboratory of Medical Molecular Biology grant (2060204)Beijing municipal government grant (YB20081002301)
文摘Objective To study the regulatory roles of SIRT1 on EZH2 expression and the further ef-fects on EZH2's repression of target gene expression. Methods The stable SIRT1 RNAi and Control RNAi HeLa cells were established by in-fection with retroviruses expressing shSIRT1 and shLuc respectively followed by puromycin selection. EZH2 protein level was detected by Western blot in either whole cell lysate or the fractional cell extract. Reverse transcription-polymerase chain reaction was performed to detect the mRNA level of EZH2. Cycloheximide was used to treat SIRT1 RNAi and Control RNAi cells for protein stability assay. Chromatin immunoprecipitation (ChIP) assay was applied to measure enrichment of SIRT1, EZH2, and trimethylated H3K27 (H3K27me3) at SATB1 promoter in SIRT1 RNAi and Control RNAi cells. Results Western blot results showed that EZH2 protein level increased upon SIRT1 de-pletion. Fractional extraction results showed unchanged cytoplasmic fraction and increased chromatin fraction of EZH2 protein in SIRT1 RNAi cells. The mRNA level of EZH2 was not affected by knockdown of SIRT1. SIRT1 recruitment was not detected at the promoter region of EZH2 gene locus. The protein stability assay showed that the protein stability of EZH2 increases upon SIRT1 knockdown. Upon SIRT1 depletion, EZH2 and H3K27me3 recruitment at SATB1 promoter increases and the mRNA level of SATB1 decreases. Conclusions Depletion of SIRT1 increases the protein stability of EZH2. The regulation of EZH2 protein level by SIRT1 affects the repressive effects of EZH2 on the target gene expres-sion.
文摘Due to high cost and relatively low efficiency of cellulase enzymes used for the saccharification of pretreated lignocelluloses, the improvement of cellulase secreting microorganisms is of vital importance. Trichoderma reesei QM 6a, an excellent source of cellulase was selected in the late 1960’s. at Natick Laboratories by its performance on pure cellulose (Solka Floc, Avicel) . QM 6a is the wild parent strain of best existing hypercellulolytic mutants such as Rut C30, VTT-D-80133, L27, CL-847 and others. Utilization of cheaper carbon sources (e.g., pretreated wood or straw) both in enzyme production and in hydrolysis necessitates to investigate fungal species other than T.reesei. A screening program was initiated to test 150 wild-type Trichoderma strains in shake flask for cellulase production on SO 2-impregnated and steam pretreated spruce and willow, candidate substrates for bioalcohol program in Sweden. Filter paper activity (FPA) method was used to determine the overall cellulase activity. Strain TUB F-1505 was selected as promising candidate for mutagenesis. This wild strain was isolated from a tropical rain forest area near Manaus, Brazil. Isolate F-1505 was subjected to NTG-mutation to select catabolite (glucose, glycerol) resistant mutants. A Petri plate clearing assay using Walseth cellulose, glycerol or glucose and Triton X100 (colony size inhibitor) was applied for pre-screening of the colonies. Over 6000 colonies were evaluated. Best colonies were tested in shake flask fermentation on pretreated spruce and willow as carbon sources. Mutants producing higher levels of cellulase (FPA) were further mutated by either NTG or UV-light. At least 4 mutants were obtained and freeze-dried exhibiting equivalent or higher cellulase production as compared to Trichoderma reesei Rut C30.
文摘As a genre that expressed women＇s dark protests, fantasies and the fear, female Gothic was not theorized until the late 1960s, and before its theorization, this convention was adopted by many women writers in their works. Charlotte Perkins Gilman＇s The yellow wallpaper is one of the many examples. As the epitome of female gothic, The yellow wallpaper utilized the female gothic conventions--the grotesque symbol of yellow wallpaper, the hysteric narrative format and the archetype image of madwoman, to express women＇s status of her time--their repression, rebellion and quest for the ＂true self＂.
文摘This paper carries out empirical analysis of the ration behavior of rural credit cooperatives in less developed regions in providing loan services to rural households. It also inspects the interaction between rural households＇ demand for credit and the loan supply from rural credit cooperatives with simultaneous discrete model. The performance of supporting agriculture through a new round reform of rural credit cooperatives is doubtable in this sample region.
文摘Increasing density is one of the important factors for producing high quality powder metallurgy （PM） parts, which has beneficial effect on mechanical properties. One of the common techniques for achieving this goal is double compacting, which seems to be a potentially attractive method in PM route, also for Cr-Mo alloyed-steels. The objective of this research was to investigate the effect of first compacting pressure and intermediate annealing temperature on attaining higher densities and minimum interconnected porosity for Cr-Mo pre-alloyed steel. The effect of mentioned parameters was studied by measuring density, transverse rupture strength and macrohardness of repressed samples. The results show that for each first compacting pressure, the density range of repressed samples increases with the increasing annealing temperature up to a certain limit, due to C dissolution which causes free porosity and further densifieation. Annealing temperatures higher than optimum one should be avoided, since too much carbon dissolution results in harder and less deformable compacts. On the other hand, with regard to repressed density and other resulted properties, the amount of first compacting pressure offers considerable advantage in obtaining higher level of density and consequently improved mechanical properties.
基金the National Natural Science Foundation of China(Grant Nos.32170192 and 32000103)Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(Grant No.2021C02064)+1 种基金Key Research and Development Project of China National Rice Research Institute(Grant No.CNRRI-2020-04)the Chinese Academy of Agricultural Sciences under the‘Elite Youth’Program and the Agricultural Sciences and Technologies Innovation Program.
文摘Polycomb repressive complex 2(PRC2)contributes to catalyze the methylation of histone H3 at lysine 27 and plays vital roles in transcriptional silencing and growth development in various organisms.In Magnaporthe oryzae,histone H3K27 is found to associate with altered transcription of in planta induced genes.However,it is still unknown whether and how H3K27me3 modification is involved in pathogenicity to rice and stress response.In this study,we found that core subunits of PRC2,Kmt6-Suz12-Eed,were required for fungal pathogenicity to rice in M.oryzae.Kmt6-Suz12-Eed localized in the nuclei and was necessary for the establishment of H3K27me3 modification.With ChIP-seq analysis,9.0%of genome regions enriched with H3K27me3 occupancy,which corresponded to 1033 genes in M.oryzae.Furthermore,deletion of Kmt6,Suz12 or Eed altered genome-wide transcriptional expression,while the de-repression genes in theΔkmt6 strain were highly associated with H3K27me3 occupancy.Notably,plenty of genes which encode effectors and secreted enzymes,secondary metabolite synthesis genes,and cell wall stress-responsive genes were directly occupied with H3K27me3 modification and de-repression in theΔkmt6 strain.These results elaborately explained how PRC2 was required for pathogenicity,which is closely related to effector modulated host immunity and host environment adaption.
基金supported by the grants from the National Key Research and Development Program of China (2016YFD0100406)the Rice Molecular Design Breeding (2016YFD0101801)+1 种基金the National Natural Science Foundation of China (91535102 and 31771760)the Open Research Fund of State Key Laboratory of Hybrid Rice (Hunan Hybrid Rice Research Center) (2016KF09)
文摘Rice grain size is an important trait that affects rice yield and quality, and thus the identification of genes related to grain size is of great significance for improving rice yield and quality. Many genes related to grain size, such as DEP1(Huang et al., 2009),GW5(Liu et al., 2017).
基金the Key Projects of Zhejiang Provincial Natural Science Foundation,China(Grant No.LZ23C130002)the National Natural Science Foundation of China(Grant No.32100161)+3 种基金the Zhejiang Science and Technology Major Program on Rice New Variety Breeding,China(Grant No.2021C02063)the Key R&D Project of China National Rice Research Institute(Grant No.CNRRI-2020-04)the Chinese Academy of Agricultural Sciences under the Agricultural Sciences and Technologies Innovation Program,the Youth innovation Program of Chinese Academy of Agricultural Sciences(Grant No.Y2023QC22)the Joint Open Competitive Project of the Yazhou Bay Seed Laboratory and China National Seed Company Limited(Grant Nos.B23YQ1514 and B23CQ15EP).
文摘The rice false smut disease, caused by Ustilaginoidea virens, has emerged as a significantglobal threat to rice production. The mechanism of carbon catabolite repression plays a crucial role in theefficient utilization of carbon nutrients and enzyme regulation in the presence of complex nutritionalconditions. Although significant progress has been made in understanding carbon catabolite repression infungi such as Aspergillus nidulans and Magnaporthe oryzae, its role in U. virens remains unclear. Toaddress this knowledge gap, we identified UvCreA, a pivotal component of carbon catabolite repression,in U. virens. Our investigation revealed that UvCreA localized to the nucleus. Deletion of UvCreA resultedin decreased growth and pathogenicity in U. virens. Through RNA-seq analysis, it was found that theknockout of UvCreA led to the up-regulation of 514 genes and down-regulation of 640 genes. Moreover,UvCreA was found to be involved in the transcriptional regulation of pathogenic genes and genesassociated with carbon metabolism in U. virens. In summary, our findings indicated that UvCreA isimportant in fungal development, virulence, and the utilization of carbon sources through transcriptionalregulation, thus making it a critical element of carbon catabolite repression.
文摘Studies have provided indirect evidence that cellulolytic activity of some anaerobic bacteria is repressed by carbohydrates, such as glucose. This effect is known as carbon catabolite repression （CCR）. Previous work has found that cellulolytic activity of Clostridium cellulovorans and Eubacterium cellulosolvens are regulated. Many cellulolytic systems of these organisms are expressed only in the presence of cellulose or cellobiose （the disaccharide of cellulose）. Some of these cellulose-induced systems also appear subject to CCR when more soluble substrates, such as glucose, are also available. To determine if such repression directly effects cellulolytic activity of C. cellulovorans and E. cellulosolvens, these organisms were cultivated in media containing a glucose analog. We then measured the ability of low levels of analog to inhibit growth of the organisms when cellobiose or cellulose were the energy substrates. Our results found that growth of both C. cellulovorans and E. cellulosolvens in cellobiose-containing medium are strongly inhibited by glucose analogs. In addition, both organisms exhibited delayed and slower growth in cellulose-containing medium when a glucose analog was added. These results provide direct demonstration that these cellulolytic bacteria are subject to CCR. This repression of cellulolysis may affect both of these organisms＇ ability to serve as industrial platforms for biomass degradation, and may interfere with the contribution of E. cellulosolvens toward animal digestion of cellulose. These results were also in sharp contrast to what has been reported regarding CCR activity in Clostridium cellulolyticum, which actively expresses cellulases in the presence of low levels of glucose.
文摘The influence of high temperature repressing treatment on the segregation of phosphorus in the 93W alloy was carefully investigated by means of Auger electron spectroscope,EPMA, TEM and SEM.The segregation of phosphorus has been observed at the tungsten-tungsten grain boundaries,particularly at the tungsten-matrix interphases when the specimens were kept at the temperature in the range of 1200—1500℃ ,followed by furnace cooling.However, no segregation of phosphorus was observed at the interfaces after the specimens were re- pressed at the range of temperature,followed by furnace cooling.After investigation,the dis- locations in the matrix phase of as-repressed specimens directly influenced the phosphorus segregation to the interfaces.After annealing,the mechanical properties were reduced because of the phosphorus segregation at the interface boundaries.
文摘Aiming at the corrosion issue of oil extraction equipments caused by sulfate-reducing bacteria （SRB） reproducing in oil field affusion system, we studied the dominant strains in the SRB community and the impact of four ecological factors on the growth of the dominant strains：temperature, pH, mineralization degree and concentration of PAM （Polyacrylamine）. The feasibility of repressing the growth of SRB by changing ecological factors was also discussed. The results indicate that Desutfobacter （one genus of SRB） is the preponderant strains of the system, and the order of the effect of four ecological factors is pH 〉 temperature 〉 the concentrations of PAM 〉 mineralization degree. The optimal pH for the highest growth rate of SRB is 8.0. No growth of SRB was observed when pH 〈 4 or pH 〉 12. The optimal temperature for the growth of SRB is 40 ℃ and the ecological amplitude is 20 -50 ℃. The appropriate concentration values of PAM is 400 -800 mg/L, beyond of which the multiplication rate and growth quantity 6f cell decrease obviously. The effect of mineralization degree of SO4^2- , HCO^3- and Na^＋ on the growth of SRB has reached an extremely remarkable level, and the change of three ions＇ concentration in water obviously effects SRB： The optimum values on the main ions in the system are Cl- of 200mg/L, HCO^3- of 900 mg/L,SO4^2- of 400 mg/L, Mg^2＋ of 60 mg/L and Na^＋ of 900 mg/L. Our results indicate that it is possible to repress the growth of SRB by changing the ecological factors in nil field affusion system.
