The sea cucumber, Apostichopusjaponicus, undergoes aestivation to improve survival during periods of high-temperature. During aestivation, the metabolic rate is depressed to reduce the consumption of reserved energy. ...The sea cucumber, Apostichopusjaponicus, undergoes aestivation to improve survival during periods of high-temperature. During aestivation, the metabolic rate is depressed to reduce the consumption of reserved energy. We evaluated the role of epigenetic modification on global gene silencing during metabolic rate depression in the sea cucumber. We compared the expression of epigenetic modifiers in active and aestivating sea cucumbers. The expression of three genes involved in DNA methylation and chromatin remodeling （DNA （cytosine-5）-methyltransferase l, Methyl-CpG-binding domain protein 2）, and Chromodomain-helicase-DNA-binding protein 5） was significantly higher during aestivation （Days 20 and 40）. Similarly, we observed an increase in the expression of genes involved in histone acetylation （Histone deacetylase 3） and Histone-binding protein RBBP4） during the early （Days 5 and 10） and late phases （Days 20 and 40） of aestivation. There was no change in the expression of KAT2B, a histone acetyltransferase. However, the expression of histone methylation associated modifiers （Histone-arginine methyltransferase CARMER and Histone-lysine N-methyltransferase MLL5） was significantly higher after 5 d in the aestivating group. The results suggest that the expression of epigenetic modifiers involved in DNA methylation, chromatin remodeling, histone acetylation, and histone methylation is upregulated during aestivation. We hypothesize that these changes regulate global gene silencing during aestivation in A. japonicus.展开更多
To establish a rapid quantification method for heparinase I during its production in recombinant Escherichia coli, a translational fusion vector was constructed by fusing the N terminus of heparinase I to the C termin...To establish a rapid quantification method for heparinase I during its production in recombinant Escherichia coli, a translational fusion vector was constructed by fusing the N terminus of heparinase I to the C terminus of a green fluorescent protein mutant （GFPmutl）. As a result, not only was the functional recombinant expression of heparinase I in E. coli accomplished, but also a linear correlation was obtained between the GFP fluorescence intensity and heparinase I activity, allowing enzyme activity to be quantified rapidly during the fermentation.展开更多
Purpose： To extract protein, decrease the cellulose and facilitate the digestion and absorption of brewers＇ spent grain by animal. Topic： Discuss and optimize the hydrolysis conditions of the combined enzymatic hyd...Purpose： To extract protein, decrease the cellulose and facilitate the digestion and absorption of brewers＇ spent grain by animal. Topic： Discuss and optimize the hydrolysis conditions of the combined enzymatic hydrolysis by Novozymes. Method： The fresh brewers＇ spent grain was firstly dried, smashed and sifted. Then as indicators of the protein extraction rate in the enzyme solution and the content of cellulose in the index, the parameters of enzymatic hydrolysis, such as the solid-liquid ratio, reaction temperature, pH, enzyme dosage and reaction time, were investigated in detailed. After hydrolysis, the brewers＇ spent grain was put in the boiling water bath for inactivation for 15 minutes, and centrifuged, the supernatants were volume to 100 mL and the protein content was measured. After the precipitate was dried, the cellulose content was also measured. Achievements： The optimized conditions were with temperature of 50 ℃, pH 6.5, enzyme amount of 30 mg for Novozymes enzyme and 2.5 h for reaction time. Under these conditions, the protein extraction rate in the enzyme reaction reached 41.82%, and the cellulose content reached 13.90%, the degradation rate of cellulose was 18.86%.展开更多
Thymidylate synthase （TS, E.C.2.1.1.45） catalyzes a critical reaction in the only pathway of de novo synthesis of thymidylate （dTMP） in human cells, and is an important target of chemotherapy. To evaluate the inhi...Thymidylate synthase （TS, E.C.2.1.1.45） catalyzes a critical reaction in the only pathway of de novo synthesis of thymidylate （dTMP） in human cells, and is an important target of chemotherapy. To evaluate the inhibitory activities of novel compounds to TS, a convenient method of activity assay using 6x His-tagged recombinant human TS （rhTS） was established and 49 novel synthetic folate analogues were screened to discover potential TS inhibitors. During the process, 4 novel compounds were found to effectively inhibit TS, while the IC 50 of a positive control raltitrexed was 3.4 μM in this assay.展开更多
Recent studies on enzymes regulating dynamic N6-methyl-adenosine （m6A） in RNA together with the findings from m6A-methylated RNA immunoprecipitation followed by high-throughput sequencing （MeRIP-seq/m6A- seq） have...Recent studies on enzymes regulating dynamic N6-methyl-adenosine （m6A） in RNA together with the findings from m6A-methylated RNA immunoprecipitation followed by high-throughput sequencing （MeRIP-seq/m6A- seq） have revealed a broad biological role of m6A in RNA processing, development, differentiation, metabolism and fertility. RNA m6A methylation is catalyzed by a multi- component methyltransferase complex composed of at least three subunits： METTL3, METTL14 and Wilms tumor 1-associated protein （WTAP）, in which METTL3 and METTL14 serve as catalytic subunits, while WTAP as reg- ulatory subunit. Dioxygenases FTO and ALKBH5, as the first two known m6A demethylases, catalyze m6A removal. Five m6A-binding proteins are classified into cytoplasmic YT521-B homology （YTH） domain-containing family YT- HDF1-3 and nuclear YTHDC1-2. Perturbation of enzy- matic activities catalyzing dynamic m6A results in altered expression of thousands of genes and affects mRNA stability and splicing at the cellular level. Here, we summarize recent discoveries about m6A methyltransferases （writers）,demethylases （erasers） and binding proteins （readers）, and further discuss the potential impacts of m6A on RNA pro- cessing, especially on mRNA splicing.展开更多
The complete sequences of the mitochondrial DNA genomes of Panthera tigris,Panthera pardus,and Panthera uncia were determined using the polymerase chain reaction method.The lengths of the complete mitochondrial DNA se...The complete sequences of the mitochondrial DNA genomes of Panthera tigris,Panthera pardus,and Panthera uncia were determined using the polymerase chain reaction method.The lengths of the complete mitochondrial DNA sequences of the three species were 16990,16964,and 16773 bp,respectively.Each of the three mitochondrial DNA genomes included 13 protein-coding genes,22 tRNA,two rRNA,one O L R,and one control region.The structures of the genomes were highly similar to those of Felis catus,Acinonyx jubatus,and Neofelis nebulosa.The phylogenies of the genus Panthera were inferred from two combined mitochondrial sequence data sets and the complete mitochondrial genome sequences,by MP (maximum parsimony),ML (maximum likelihood),and Bayesian analysis.The results showed that Panthera was composed of Panthera leo,P.uncia,P.pardus,Panthera onca,P.tigris,and N.nebulosa,which was included as the most basal member.The phylogeny within Panthera genus was N.nebulosa (P.tigris (P.onca (P.pardus,(P.leo,P.uncia)))).The divergence times for Panthera genus were estimated based on the ML branch lengths and four well-established calibration points.The results showed that at about 11.3 MYA,the Panthera genus separated from other felid species and then evolved into the several species of the genus.In detail,N.nebulosa was estimated to be founded about 8.66 MYA,P.tigris about 6.55 MYA,P.uncia about 4.63 MYA,and P.pardus about 4.35 MYA.All these estimated times were older than those estimated from the fossil records.The divergence event,evolutionary process,speciation,and distribution pattern of P.uncia,a species endemic to the central Asia with core habitats on the Qinghai-Tibetan Plateau and surrounding highlands,mostly correlated with the geological tectonic events and intensive climate shifts that happened at 8,3.6,2.5,and 1.7 MYA on the plateau during the late Cenozoic period.展开更多
OBJECTIVE:To study on effects of Lichong decoction on expression of apoptosis-controlling genes,Bcl-2 and Bcl-2-associated X protein(Bax) mRNAs in hysteromyoma tissue of the hysteromyoma model rat.METHODS:Fifty Wistar...OBJECTIVE:To study on effects of Lichong decoction on expression of apoptosis-controlling genes,Bcl-2 and Bcl-2-associated X protein(Bax) mRNAs in hysteromyoma tissue of the hysteromyoma model rat.METHODS:Fifty Wistar female rats were randomly divided into a normal group,a model group,a Lichong decoction group,a Guizifuling capsule group and a Mifepristone group.The hysteromyoma rat model was established by intraperitoneal injection of exogenous estrin and progestogens.Pathological examination of uterine tissue,uterine coefficient and uterine transverse diameter were made under optic microscope and expressions of Bcl-2 and Bax mRNAs in uterine tissue in the groups were detected with real-time fluorescent quantitative polymerase chain reaction(PCR) technique.RESULTS:After treatment,under microscope it was found that in the Lichong decoction group myometrium thinned,muscle fiber slightly overgrowth or long and thin,regular arrangement,inserting phenomenon of inner circular muscle and external longitudinal muscle was occasionally or not seen in the Lichong decoction group.The uterine coefficient and the uterine transverse diameter significantly decreased(P<0.01),and Bcl-2 mRNA expression significantly decreased(P<0.01) and Bax mRNA expression significantly increased in hysteromyoma tissue(P<0.01) in the Lichong decoction group as compared with the model group.CONCLUSION:Therapeutic effects of Lichong decoction on hysteromyoma is related with decrease of Bcl-2 mRNA expression and increase of Bax mRNA expression.展开更多
Activating transcription factor 5(ATF5) is a member of the activating transcription factor/cA MP response element binding protein(ATF/CREB) family, and is highly expressed in liver and adipose tissue. Previous reports...Activating transcription factor 5(ATF5) is a member of the activating transcription factor/cA MP response element binding protein(ATF/CREB) family, and is highly expressed in liver and adipose tissue. Previous reports have shown that ATF5 promoted 3T3-L1 preadipocytes differentiation. In this study, we found that ATF5 was highly expressed in mature adipocytes, suggesting a potential role of ATF5 in mature adipocytes, which has not been reported previously. To understand the function of ATF5 in mature adipocytes, we knocked down the expression of ATF5 in 3T3-L1 mature adipocytes and observed decreased lipid droplets. Consistent with the in vitro experiment, the knockdown of ATF5 in white adipose tissue led to less adipose tissue and smaller adipocytes size. Further research revealed that the inhibition of ATF5 diminished the adipocytes size via the inhibition of fatty acid synthetase, stearyl coenzyme A desaturation enzyme 1, and the induction of carnitine palmitoyl transferase 1, one key enzyme of lipid metabolism. In addition, ATF5 knockdown in inguinal white adipose tissue improved whole body insulin sensitivity.Our work provides a new understanding of ATF5 function in mature adipocytes and a potential therapeutic target of diabetes.展开更多
Euryarchaeota and Crenarchaeota, the two main lineages of the domain Archaea, encode different chromatin proteins and differ in the use of replicative DNA polymerases. Crenarchaea possess a single family B DNA polymer...Euryarchaeota and Crenarchaeota, the two main lineages of the domain Archaea, encode different chromatin proteins and differ in the use of replicative DNA polymerases. Crenarchaea possess a single family B DNA polymerase(Pol B), which is capable of strand displacement modulated by the chromatin proteins Cren7 and Sul7 d. Euryarchaea have two distinct replicative DNA polymerases, PolB and PolD, a family D DNA polymerase. Here we characterized the strand displacement activities of Pol B and Pol D from the hyperthermophilic euryarchaeon Pyrococcus furiosus and investigated the influence of HPf A1, a homolog of eukaryotic histones from P. furiosus, on these activities. We showed that both Pol B and Pol D were efficient in strand displacement. HPf A1 inhibited DNA strand displacement by both DNA polymerases but exhibited little effect on the displacement of a RNA strand annealed to single-stranded template DNA. This is consistent with the finding that HPf A1 bound more tightly to double-stranded DNA than to a RNA:DNA hybrid. Our results suggest that, although crenarchaea and euryarchaea differ in chromosomal packaging, they share similar mechanisms in modulating strand displacement by DNA polymerases during lagging strand DNA synthesis.展开更多
Objective：Autophagy is involved in several neurodegenerative diseases and recently its role in acute brain injury has won increasing interest.Spinal cord injuries （SCIs） often lead to permanent neurological deficit...Objective：Autophagy is involved in several neurodegenerative diseases and recently its role in acute brain injury has won increasing interest.Spinal cord injuries （SCIs） often lead to permanent neurological deficit.Therefore,in this study,we examined the profiles of autophagy-linked proteins （MAP-LC3） after SCI to investigate whether the expression of autophagy contributes to neurological deficit after SCI.Methods：Adult female Sprague-Dawley rats were used and randomly divided into control and SCI groups.All the rates received laminectomy at T8-T10 level.Those in the SCI group received additional exposure of the dorsal surface of the spinal cord,followed by a weightdrop injury.Thereafter we investigated the expression levels of MAP-LC3,beclin-1,Cathepsin D and the beclin-1-binding protein bcl-2 by western blot analysis at 12 h,24 h,3 d,7 d,21 d and 28 d.One-way ANOVA with Tukey post hoc test was used to compare data between groups.Results：We observed significant increase in the level of LC3 （LC3-Ⅱ/LC3-Ⅰ） at 3 d and 7 d after SCI when compared with the sham group.While the level of beclin-1 and ratio of beclin-1/bcl-2 was found to have increased from 12 h to 24 h after injury.Cathepsin D expression was also elevated at 7 d （P＜0.01）.Conclusion：Based on the above mentioned data,we proposed that autophagy plays a role in the manifestation of cell injury following SCI.展开更多
It is in a great demand to design a biodegradable, tumor microenvironment-sensitive drug delivery system to achieve safe and highly efficacious treatment of cancer.Herein, a novel pH/enzyme sensitive dendritic pdi HPM...It is in a great demand to design a biodegradable, tumor microenvironment-sensitive drug delivery system to achieve safe and highly efficacious treatment of cancer.Herein, a novel pH/enzyme sensitive dendritic pdi HPMADOX conjugate was designed. di HPMA dendritic copolymer with GFLG segments in the branches which are sensitive to the intracellular enzyme of the tumor was prepared through RAFT polymerization. DOX was attached to dendritic di HPMA polymer through a pH-sensitive hydrazone bond. The dendritic pdi HPMA-DOX conjugate self-assembled into nanoparticles with an ideal spherical shape at a mean size of 103 nm. The DOX attached to the polymeric carrier was released in an acidic environment, and the GFLG linker for synthesizing the dendritic vehicle with a high molecular weight（M_W, 220 kDa） was cleaved to release low MWsegments（〈40 kDa） in the presence of cathepsin B. The dendritic polymeric conjugate was internalized via an endocytic pathway, and then released the anticancer drug, which led to significant cytotoxicity for tumors. The blood circulation time was profoundly prolonged, resulting in high accumulation of DOX into tumors. In vivo anti-tumor experiments with 4 T1 tumor bearing mice demonstrated that the conjugate had a better antitumor efficacy in comparison with free DOX. Additionally, body weight measurements and histological examinations indicated that the conjugate showed low toxicities to normal tissues. This dendritic polymeric drug carrier in a response to intracellular enzyme and acidic pH of tumor tissue or cells holds great promise in tumor-targeted therapy.展开更多
基金Supported by the National Key Technology Research and Development Program(No.2006AA10A411)the Agricultural Seed Project of Shandong Province
文摘The sea cucumber, Apostichopusjaponicus, undergoes aestivation to improve survival during periods of high-temperature. During aestivation, the metabolic rate is depressed to reduce the consumption of reserved energy. We evaluated the role of epigenetic modification on global gene silencing during metabolic rate depression in the sea cucumber. We compared the expression of epigenetic modifiers in active and aestivating sea cucumbers. The expression of three genes involved in DNA methylation and chromatin remodeling （DNA （cytosine-5）-methyltransferase l, Methyl-CpG-binding domain protein 2）, and Chromodomain-helicase-DNA-binding protein 5） was significantly higher during aestivation （Days 20 and 40）. Similarly, we observed an increase in the expression of genes involved in histone acetylation （Histone deacetylase 3） and Histone-binding protein RBBP4） during the early （Days 5 and 10） and late phases （Days 20 and 40） of aestivation. There was no change in the expression of KAT2B, a histone acetyltransferase. However, the expression of histone methylation associated modifiers （Histone-arginine methyltransferase CARMER and Histone-lysine N-methyltransferase MLL5） was significantly higher after 5 d in the aestivating group. The results suggest that the expression of epigenetic modifiers involved in DNA methylation, chromatin remodeling, histone acetylation, and histone methylation is upregulated during aestivation. We hypothesize that these changes regulate global gene silencing during aestivation in A. japonicus.
基金Supported by the National Natural Science Foundation of China (No.20336010 and No.20176025).
文摘To establish a rapid quantification method for heparinase I during its production in recombinant Escherichia coli, a translational fusion vector was constructed by fusing the N terminus of heparinase I to the C terminus of a green fluorescent protein mutant （GFPmutl）. As a result, not only was the functional recombinant expression of heparinase I in E. coli accomplished, but also a linear correlation was obtained between the GFP fluorescence intensity and heparinase I activity, allowing enzyme activity to be quantified rapidly during the fermentation.
文摘Purpose： To extract protein, decrease the cellulose and facilitate the digestion and absorption of brewers＇ spent grain by animal. Topic： Discuss and optimize the hydrolysis conditions of the combined enzymatic hydrolysis by Novozymes. Method： The fresh brewers＇ spent grain was firstly dried, smashed and sifted. Then as indicators of the protein extraction rate in the enzyme solution and the content of cellulose in the index, the parameters of enzymatic hydrolysis, such as the solid-liquid ratio, reaction temperature, pH, enzyme dosage and reaction time, were investigated in detailed. After hydrolysis, the brewers＇ spent grain was put in the boiling water bath for inactivation for 15 minutes, and centrifuged, the supernatants were volume to 100 mL and the protein content was measured. After the precipitate was dried, the cellulose content was also measured. Achievements： The optimized conditions were with temperature of 50 ℃, pH 6.5, enzyme amount of 30 mg for Novozymes enzyme and 2.5 h for reaction time. Under these conditions, the protein extraction rate in the enzyme reaction reached 41.82%, and the cellulose content reached 13.90%, the degradation rate of cellulose was 18.86%.
基金supported by National Natural Science Foundation of China(Grant No.20972011,21042009,21172014)
文摘Thymidylate synthase （TS, E.C.2.1.1.45） catalyzes a critical reaction in the only pathway of de novo synthesis of thymidylate （dTMP） in human cells, and is an important target of chemotherapy. To evaluate the inhibitory activities of novel compounds to TS, a convenient method of activity assay using 6x His-tagged recombinant human TS （rhTS） was established and 49 novel synthetic folate analogues were screened to discover potential TS inhibitors. During the process, 4 novel compounds were found to effectively inhibit TS, while the IC 50 of a positive control raltitrexed was 3.4 μM in this assay.
基金supported by the National BasicResearch Program of China(2011CB510103,2014CB964902)the National Science Foundation of China(91319308,31430022 and31400672)Strategic Priority Research Program of Chinese Academy ofSciences(XDB14030300)
文摘Recent studies on enzymes regulating dynamic N6-methyl-adenosine （m6A） in RNA together with the findings from m6A-methylated RNA immunoprecipitation followed by high-throughput sequencing （MeRIP-seq/m6A- seq） have revealed a broad biological role of m6A in RNA processing, development, differentiation, metabolism and fertility. RNA m6A methylation is catalyzed by a multi- component methyltransferase complex composed of at least three subunits： METTL3, METTL14 and Wilms tumor 1-associated protein （WTAP）, in which METTL3 and METTL14 serve as catalytic subunits, while WTAP as reg- ulatory subunit. Dioxygenases FTO and ALKBH5, as the first two known m6A demethylases, catalyze m6A removal. Five m6A-binding proteins are classified into cytoplasmic YT521-B homology （YTH） domain-containing family YT- HDF1-3 and nuclear YTHDC1-2. Perturbation of enzy- matic activities catalyzing dynamic m6A results in altered expression of thousands of genes and affects mRNA stability and splicing at the cellular level. Here, we summarize recent discoveries about m6A methyltransferases （writers）,demethylases （erasers） and binding proteins （readers）, and further discuss the potential impacts of m6A on RNA pro- cessing, especially on mRNA splicing.
基金supported by grants from the National Natural Science Foundation of China (Grant Nos:30470244 and 30870359)the Foundations for Excellent Youth in Anhui Province (Grant No:04043409)+1 种基金the National Natural Science Foundation of Education Department of Anhui Province (Grant No:KJ2009B015)the Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province
文摘The complete sequences of the mitochondrial DNA genomes of Panthera tigris,Panthera pardus,and Panthera uncia were determined using the polymerase chain reaction method.The lengths of the complete mitochondrial DNA sequences of the three species were 16990,16964,and 16773 bp,respectively.Each of the three mitochondrial DNA genomes included 13 protein-coding genes,22 tRNA,two rRNA,one O L R,and one control region.The structures of the genomes were highly similar to those of Felis catus,Acinonyx jubatus,and Neofelis nebulosa.The phylogenies of the genus Panthera were inferred from two combined mitochondrial sequence data sets and the complete mitochondrial genome sequences,by MP (maximum parsimony),ML (maximum likelihood),and Bayesian analysis.The results showed that Panthera was composed of Panthera leo,P.uncia,P.pardus,Panthera onca,P.tigris,and N.nebulosa,which was included as the most basal member.The phylogeny within Panthera genus was N.nebulosa (P.tigris (P.onca (P.pardus,(P.leo,P.uncia)))).The divergence times for Panthera genus were estimated based on the ML branch lengths and four well-established calibration points.The results showed that at about 11.3 MYA,the Panthera genus separated from other felid species and then evolved into the several species of the genus.In detail,N.nebulosa was estimated to be founded about 8.66 MYA,P.tigris about 6.55 MYA,P.uncia about 4.63 MYA,and P.pardus about 4.35 MYA.All these estimated times were older than those estimated from the fossil records.The divergence event,evolutionary process,speciation,and distribution pattern of P.uncia,a species endemic to the central Asia with core habitats on the Qinghai-Tibetan Plateau and surrounding highlands,mostly correlated with the geological tectonic events and intensive climate shifts that happened at 8,3.6,2.5,and 1.7 MYA on the plateau during the late Cenozoic period.
基金Supported by Beijing City Natural Science Fund (No.7082015)National Natural Science Fund (No. 81073096)"Middle-young Aged Core Talent Cultural Plant" of Beijing City University Talent Strengthening Education Plant (No.PHR201008403)
文摘OBJECTIVE:To study on effects of Lichong decoction on expression of apoptosis-controlling genes,Bcl-2 and Bcl-2-associated X protein(Bax) mRNAs in hysteromyoma tissue of the hysteromyoma model rat.METHODS:Fifty Wistar female rats were randomly divided into a normal group,a model group,a Lichong decoction group,a Guizifuling capsule group and a Mifepristone group.The hysteromyoma rat model was established by intraperitoneal injection of exogenous estrin and progestogens.Pathological examination of uterine tissue,uterine coefficient and uterine transverse diameter were made under optic microscope and expressions of Bcl-2 and Bax mRNAs in uterine tissue in the groups were detected with real-time fluorescent quantitative polymerase chain reaction(PCR) technique.RESULTS:After treatment,under microscope it was found that in the Lichong decoction group myometrium thinned,muscle fiber slightly overgrowth or long and thin,regular arrangement,inserting phenomenon of inner circular muscle and external longitudinal muscle was occasionally or not seen in the Lichong decoction group.The uterine coefficient and the uterine transverse diameter significantly decreased(P<0.01),and Bcl-2 mRNA expression significantly decreased(P<0.01) and Bax mRNA expression significantly increased in hysteromyoma tissue(P<0.01) in the Lichong decoction group as compared with the model group.CONCLUSION:Therapeutic effects of Lichong decoction on hysteromyoma is related with decrease of Bcl-2 mRNA expression and increase of Bax mRNA expression.
基金supported by the National Key Basic Research Project (2013CB530601 to X. Li)the National Natural Science Foundation of China (81270954, 31571401 to X. Li)
文摘Activating transcription factor 5(ATF5) is a member of the activating transcription factor/cA MP response element binding protein(ATF/CREB) family, and is highly expressed in liver and adipose tissue. Previous reports have shown that ATF5 promoted 3T3-L1 preadipocytes differentiation. In this study, we found that ATF5 was highly expressed in mature adipocytes, suggesting a potential role of ATF5 in mature adipocytes, which has not been reported previously. To understand the function of ATF5 in mature adipocytes, we knocked down the expression of ATF5 in 3T3-L1 mature adipocytes and observed decreased lipid droplets. Consistent with the in vitro experiment, the knockdown of ATF5 in white adipose tissue led to less adipose tissue and smaller adipocytes size. Further research revealed that the inhibition of ATF5 diminished the adipocytes size via the inhibition of fatty acid synthetase, stearyl coenzyme A desaturation enzyme 1, and the induction of carnitine palmitoyl transferase 1, one key enzyme of lipid metabolism. In addition, ATF5 knockdown in inguinal white adipose tissue improved whole body insulin sensitivity.Our work provides a new understanding of ATF5 function in mature adipocytes and a potential therapeutic target of diabetes.
基金supported by the National Natural Science Foundation of China (31130003, 30921065)
文摘Euryarchaeota and Crenarchaeota, the two main lineages of the domain Archaea, encode different chromatin proteins and differ in the use of replicative DNA polymerases. Crenarchaea possess a single family B DNA polymerase(Pol B), which is capable of strand displacement modulated by the chromatin proteins Cren7 and Sul7 d. Euryarchaea have two distinct replicative DNA polymerases, PolB and PolD, a family D DNA polymerase. Here we characterized the strand displacement activities of Pol B and Pol D from the hyperthermophilic euryarchaeon Pyrococcus furiosus and investigated the influence of HPf A1, a homolog of eukaryotic histones from P. furiosus, on these activities. We showed that both Pol B and Pol D were efficient in strand displacement. HPf A1 inhibited DNA strand displacement by both DNA polymerases but exhibited little effect on the displacement of a RNA strand annealed to single-stranded template DNA. This is consistent with the finding that HPf A1 bound more tightly to double-stranded DNA than to a RNA:DNA hybrid. Our results suggest that, although crenarchaea and euryarchaea differ in chromosomal packaging, they share similar mechanisms in modulating strand displacement by DNA polymerases during lagging strand DNA synthesis.
文摘Objective：Autophagy is involved in several neurodegenerative diseases and recently its role in acute brain injury has won increasing interest.Spinal cord injuries （SCIs） often lead to permanent neurological deficit.Therefore,in this study,we examined the profiles of autophagy-linked proteins （MAP-LC3） after SCI to investigate whether the expression of autophagy contributes to neurological deficit after SCI.Methods：Adult female Sprague-Dawley rats were used and randomly divided into control and SCI groups.All the rates received laminectomy at T8-T10 level.Those in the SCI group received additional exposure of the dorsal surface of the spinal cord,followed by a weightdrop injury.Thereafter we investigated the expression levels of MAP-LC3,beclin-1,Cathepsin D and the beclin-1-binding protein bcl-2 by western blot analysis at 12 h,24 h,3 d,7 d,21 d and 28 d.One-way ANOVA with Tukey post hoc test was used to compare data between groups.Results：We observed significant increase in the level of LC3 （LC3-Ⅱ/LC3-Ⅰ） at 3 d and 7 d after SCI when compared with the sham group.While the level of beclin-1 and ratio of beclin-1/bcl-2 was found to have increased from 12 h to 24 h after injury.Cathepsin D expression was also elevated at 7 d （P＜0.01）.Conclusion：Based on the above mentioned data,we proposed that autophagy plays a role in the manifestation of cell injury following SCI.
基金supported by the National Natural Science Foundation of China (51673127 and 8162103)International Science and Technology Cooperation Program of China (2015DFE52780 and 81220108013)International Science and Technology Cooperation Program of Chengdu (2016-GH03-00005-HZ)
文摘It is in a great demand to design a biodegradable, tumor microenvironment-sensitive drug delivery system to achieve safe and highly efficacious treatment of cancer.Herein, a novel pH/enzyme sensitive dendritic pdi HPMADOX conjugate was designed. di HPMA dendritic copolymer with GFLG segments in the branches which are sensitive to the intracellular enzyme of the tumor was prepared through RAFT polymerization. DOX was attached to dendritic di HPMA polymer through a pH-sensitive hydrazone bond. The dendritic pdi HPMA-DOX conjugate self-assembled into nanoparticles with an ideal spherical shape at a mean size of 103 nm. The DOX attached to the polymeric carrier was released in an acidic environment, and the GFLG linker for synthesizing the dendritic vehicle with a high molecular weight（M_W, 220 kDa） was cleaved to release low MWsegments（〈40 kDa） in the presence of cathepsin B. The dendritic polymeric conjugate was internalized via an endocytic pathway, and then released the anticancer drug, which led to significant cytotoxicity for tumors. The blood circulation time was profoundly prolonged, resulting in high accumulation of DOX into tumors. In vivo anti-tumor experiments with 4 T1 tumor bearing mice demonstrated that the conjugate had a better antitumor efficacy in comparison with free DOX. Additionally, body weight measurements and histological examinations indicated that the conjugate showed low toxicities to normal tissues. This dendritic polymeric drug carrier in a response to intracellular enzyme and acidic pH of tumor tissue or cells holds great promise in tumor-targeted therapy.
