The effects of different concentrations of cadmium chloride ranging from 0.5 to 20 ppm on the nucleolus in root tip cells of Allium cepa were studied using the silver staining technique. The results indicated that aft...The effects of different concentrations of cadmium chloride ranging from 0.5 to 20 ppm on the nucleolus in root tip cells of Allium cepa were studied using the silver staining technique. The results indicated that after the treatment with Cd ̄(2+),different changes in nucleolar morphology appeared. The nucleolar material was extruded from the nucleus into the cytoplasm,and the nucleoli at mitotic metaphase did not disappear. Apparently,cadmium showed a specific effects on the nucleoli in root tip cells of Allium cepa. The possible mechanism behind this phenomenon is also briefly discussed.展开更多
In our conversation with Prof.CHEN Lingling on the"dark mat ter"in the genome,namely the non-coding RNAs,we got to know two classes of long non-coding RNAs(lncRNAs)in close association with Prader-Willi synd...In our conversation with Prof.CHEN Lingling on the"dark mat ter"in the genome,namely the non-coding RNAs,we got to know two classes of long non-coding RNAs(lncRNAs)in close association with Prader-Willi syndrome(PWS).Each with a snoRNA cap on its either end,they fall in the sno-lncRNA family,a group of lncRNAs identified by CHEN’s group in their earlier research.Here we are meeting another member of the family,SLERT,a rescuer展开更多
Mitochondrial damage is closely related to the occurrence of many diseases.However,accurate monitoring and reporting of mitochondrial damage are not easy.Here,we developed a small molecule fluorescent probe named CB-C...Mitochondrial damage is closely related to the occurrence of many diseases.However,accurate monitoring and reporting of mitochondrial damage are not easy.Here,we developed a small molecule fluorescent probe named CB-Cl,which has splendid spectral properties(large Stokes shift,strong affinity for RNA,etc.)and excellent targeting ability to intracellular mitochondria.After mitochondria were damaged by external stimuli,CB-Cl would light up the nucleolus as a signal reporter.The cascade imaging of mitochondria and nucleolus using CB-Cl can monitor and visualize the mitochondrial status in living cells in real-time.Based on the above advantages,the probe CB-Cl has reference significance for the related research of mitochondrial damage and the prevention and treatment of related diseases.展开更多
Purpose:The collaboration relationships between innovation actors at a geographic level may be considered as grouping two separate layers,the domestic and the foreign.At the level of each layer,the relationships and t...Purpose:The collaboration relationships between innovation actors at a geographic level may be considered as grouping two separate layers,the domestic and the foreign.At the level of each layer,the relationships and the actors involved constitute a Triple Helix game.The paper distinguished three levels of analysis:the global grouping together all actors,the domestic grouping together domestic actors,and the foreign related to only actors from partner countries.Design/methodology/approach:Bibliographic records data from the Web of Science for South Korea and West Africa breakdown per innovation actors and distinguishing domestic and international collaboration are analyzed with game theory.The core,the Shapley value,and the nucleolus are computed at the three levels to measure the synergy between actors.Findings:The synergy operates more in South Korea than in West Africa;the government is more present in West Africa than in South Korea;domestic actors create more synergy in South Korea,but foreign more in West Africa;South Korea can consume all the foreign synergy,which is not the case of West Africa.Research limitations:Research data are limited to publication records;techniques and methods used may be extended to other research outputs.Practical implications:West African governments should increase their investment in science,technology,and innovation to benefit more from the synergy their innovation actors contributed at the foreign level.However,the results of the current study may not be sufficient to prove that greater investment will yield benefits from foreign synergies.Originality/value:This paper uses game theory to assess innovation systems by computing the contribution of foreign actors to knowledge production at an area level.It proposes an indicator to this end.展开更多
We observed the ultrastructure of nucleolus in rat liver cells by conventional electron microscopy, and employed cytochemistry NAMA-Ur DNA specific stain method to analyze the distribution and position of nucleolar DN...We observed the ultrastructure of nucleolus in rat liver cells by conventional electron microscopy, and employed cytochemistry NAMA-Ur DNA specific stain method to analyze the distribution and position of nucleolar DNA in situ. The results showed that nucleolar DNA of rat liver cells comes from nucleolus-associated chromatin, and continuously extends in the dense fibrillar component (DFC) of nucleolus, localizes at the periphery of fibrillar center (FC) and in DFC. Furthermore, by employing anti-DNA/RNA hybrid antibodies, we directly and selectively labeled transcription sites of rRNA genes and testified that localization of transcription sites not only to DFC but also to the periphery of FC.展开更多
The location and configuration of nucleolar DNA have not been determined for a long time. In this paper, we have observed the nucleolar infrastructure and the character of nucleolar DNA in Allium cepa cells by convent...The location and configuration of nucleolar DNA have not been determined for a long time. In this paper, we have observed the nucleolar infrastructure and the character of nucleolar DNA in Allium cepa cells by conventional electron microscopy and the cytochemical NAMA-Ur DNA specific staining method. Furthermore, we have properly improved the NAMA-Ur method so as to analyze the location and configuration of nucleolar DNA in situ. Our results indicated that the nucleolar DNA in Allium cepa cells is mainly located at the border between fibrillar centers and dense fibribllar component, especially distributed in the configuration of encircling the fibrillar centers.展开更多
Microalgae are used in food and feed,and they are considered a potential feedstock for sustainably pro-duced chemicals and biofuel.However,production of microalgal-derived chemicals is not yet economically feasible.Ge...Microalgae are used in food and feed,and they are considered a potential feedstock for sustainably pro-duced chemicals and biofuel.However,production of microalgal-derived chemicals is not yet economically feasible.Genetic engineering could bridge the gap to industrial application and facilitate the production of novel products from microalgae.Here,we report the discovery of a novel gene expression system in the oleaginous microalga Nannochloropsis that exploits the highly efficient transcriptional activity of RNA po-lymerase I and an internal ribosome entry site for translation.We identified the nucleolus as a genomic safe harbor for Pol I transcription and used it to construct transformant strains with consistently strong trans-gene expression.The new expression system provides an outstanding tool for genetic and metabolic en-gineering of microalgae and thus will probably make substantial contributions to microalgal research.展开更多
Nucleolus organizer regions (Nor loci) of a range of Chinese wheat landraces and cultivars (Triticum aestivum L. em Thell.) were analysed using genomic DNA extracted from leaves. Only two allelic variants of the Nor-B...Nucleolus organizer regions (Nor loci) of a range of Chinese wheat landraces and cultivars (Triticum aestivum L. em Thell.) were analysed using genomic DNA extracted from leaves. Only two allelic variants of the Nor-B1 locus were found on chromosome 1B (Nor-B1a and Nor-B1g), while Nor-B1g was probably introduced from North America in the early 1960s. The even more recent introduction of the rye allele Nor-R1 in the early 1980s was also revealed. Eight allelic variants of the Nor-B2 locus on chromosome 6B (Nor-B2a, b, d, f, h, o, p and s) were identified. A Chinese origin for the a, d, f, o, p and s alkies is evident although the d allele was successfully introduced into Australian wheats in the early 1900s. Nor-B2h and Nor-B2b are again very recent introductions into Chinese wheat breeding programs, the former from CIMMYT wheats and the latter in association with the introduction of the 1RS/1BL translocation from Europe. On the basis of the presence of different combinations of Nor-B1 and Nor-B2展开更多
Nucleolus is the most prominent subnuclear structure, which performs a wide variety of functions in the eukaryotic cellular processes. In order to understand the structural and functional role of the nucleoli in bovin...Nucleolus is the most prominent subnuclear structure, which performs a wide variety of functions in the eukaryotic cellular processes. In order to understand the structural and functional role of the nucleoli in bovine cells, we analyzed the proteomic composition of the bovine nucleoli. The nucleoli were isolated from Madin Darby bovine kidney cells and subjected to proteomic analysis by LC-MS/MS after fractionation by SDS-PAGE and strong cation exchange chromatography. Analysis of the data using the Mascot database search and the GPM database search identified 311 proteins in the bovine nucleoli, which contained 22 proteins previously not identified in the proteomic analysis of human nucleoli. Analysis of the identified proteins using the GoMiner software suggested that the bovine nucleoli contained proteins involved in ribosomal biogenesis, cell cycle control, transcriptional, translational and post-translational regulation, transport, and structural organization.展开更多
The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,ce...The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,cellular senescence,and stress response.The protein composition of the nucleolus changes dynamically through protein turnover to meet the needs of cellular activities or stress responses.Recent studies have identified a nucleolus-localized protein degradation pathway in zebrafish and humans,namely the Def-CAPN3 pathway,which is essential to ribosome production and cell-cycle progression,by controlling the turnover of multiple substrates(e.g.,ribosomal small-subunit[SSU]processome component Mpp10,transcription factor p53,check-point proteins Chk1 and Wee1).This pathway relies on the Ca2þ-dependent cysteine proteinase CAPN3 and is independent of the ubiquitin-mediated proteasome pathway.CAPN3 is recruited by nucleolar protein Def from cytoplasm to nucleolus,where it proteolyzes its substrates which harbor a CAPN3 recognition-motif.Def depletion leads to the exclusion of CAPN3 and accumulation of p53,Wee1,Chk1,and Mpp10 in the nucleolus that result in cell-cycle arrest and rRNA processing abnormality.Here,we summarize the discovery of the Def-CAPN3 pathway and propose its biological role in cell-cycle control and ribosome biogenesis.展开更多
Our conventional EM observations indicate that the nucleolus of Allium cepa is composedof the fibrillar centre (FC), fibrillar component (F) and granular region (G). FC is an elec-tron-lucid zone which contains conden...Our conventional EM observations indicate that the nucleolus of Allium cepa is composedof the fibrillar centre (FC), fibrillar component (F) and granular region (G). FC is an elec-tron-lucid zone which contains condensed or loosened chromatin. F is a circular, highly elec-tron-dense component which surrounds FC and consists of compact fibrils. EM autoradiographic(EM ARG) studies with ~3H- UdR reveal that the synthesis of ribosomal RNA (rRNA) takesplace in F. G is situated around F and composed of granules about 25 to 30 nm in diameter.EM ARG studies with ~3H- TdR demonstrate that silver grains are predominantly located in Gof the nucleolar periphery and the region of the nucleolus-associated chromatin. In addition,~3H- TdR labels are also present, but with a much lower frequency, in FC. F and G of the nu-cleolar interior. According to the distribution and sphere of silver grains in different compo-nents of the nucleolus, we suggest that the replication sites of ribosomal DNA (rDNA) aremainly located展开更多
The CRISPR/Cas9 system,originally derived from the prokaryotic adaptive immune system,has been developed as efficient genome editing tools.It enables precise gene manipulation on chromosomal DNA through the specific b...The CRISPR/Cas9 system,originally derived from the prokaryotic adaptive immune system,has been developed as efficient genome editing tools.It enables precise gene manipulation on chromosomal DNA through the specific binding of programmable sgRNA to target DNA,and the Cas9 protein,which has endonuclease activity,will cut a double strand break at specific locus.However,Cas9 is a foreign protein in mammalian cells,and the potential risks associated with its introduction into mammalian cells are not fully understood.In this study,we performed pull-down and mass spectrometry(MS)analysis of Streptococcus pyogenes Cas9(SpyCas9)interacting proteins in HEK293T cells and showed that the majority of Cas9-associated proteins identified by MS were localized in the nucleolus.Interestingly,we further discovered that the Cas9 protein contains a sequence encoding a nucleolus detention signal(NoDS).Compared with wild-type(WT)Cas9,NoDS-mutated variants of Cas9(mCas9)are less stable,although their gene editing activity is minimally affected.Overexpression of WT Cas9,but not mCas9,causes general effects on transcription and protein translation in the host cell.Overall,identification of NoDS in Cas9 will improve the understanding of Cas9's biological function in vivo,and the removal of NoDS in Cas9 may enhance its safety for future clinical use.展开更多
The effects of different concentrations of manganous sulphate on root growth,cell division, chromosome and nucleus morphplogy and nucleoli in root tip-cells of Allium cepa L. were studied. The concentrations of mangan...The effects of different concentrations of manganous sulphate on root growth,cell division, chromosome and nucleus morphplogy and nucleoli in root tip-cells of Allium cepa L. were studied. The concentrations of manganous sulphate used were 10-7,10-6,10-5 ,10-4,10-3, 10-2 and 10-1mol/L. The results indicated that manganese had a stimulatory effect on the root growth at lower concentrations (10-7 to 10-4mol/L). With increasing the concentration of Mn (10-3 to 10-1mol/L) and duration of treatment,manganese inhibited root growth and cell division, and had toxic effects on chromosomes,nuclei and nucleoli. Manganese Could induce mitotic irregularities,comprising c-mitosis,anaphase bridges and chromosome stickiness. The nuclei became irregular in shape and many micronuclei were scattered in the cytoplasm. Some similar silver-stained particulate materials were found scattered in the nucleus in root tip cells. The possible mechanism behind these phenomena is also briefly discussed.展开更多
Guanidinylated bioresponsive poly(amido amine)s polymers, CAR-CBA and CHL-CBA, weresynthesized by Michael-type addition reaction between guanidine hydrochloride(CAR) orchlorhexidine(CHL) and N,N-cystaminebisacrylamide...Guanidinylated bioresponsive poly(amido amine)s polymers, CAR-CBA and CHL-CBA, weresynthesized by Michael-type addition reaction between guanidine hydrochloride(CAR) orchlorhexidine(CHL) and N,N-cystaminebisacrylamide(CBA). Previous studies have shownthat both polymers had high transfection efficiencies as gene delivery carriers. In this study,we investigated the nucleolus localization abilities and cellular internalization pathways ofthese two polymers in gene delivery. Each polymer condensed plasmid DNA(p DNA) andformed nanoparticle complexes, and then their transfection studies were performed inMCF-7 cells. Both complexes were found enriched in nucleolus after cellular transfection,and their transfection efficiencies were significantly improved when transfection was per-formed on MCF-7 cells arrested at M phase. The transfection efficiency of CAR-CBA-pDNAwas inhibited by chlorpromazine, and cell endosomes were disrupted after being exposedto CAR-CBA-pDNA. In regards to CHL-CBA-pDNA, its transfection efficiency was not affected by three types of endocytosis inhibitors used in the study, and CHL-CBA-pDNA showed no effect on endosomes. Cellular lactate dehydrogenase release and membrane morphology were changed after cells were transfected by the two complexes. The results indicated that both CAR-CBA and CHL-CBA polymers demonstrated good nucleolus localization abilities. It was beneficial for transfection when cells were arrested at M phase. CAR-CBA-pDNA cellular internalization was involved with clathrin-mediated endocytosis pathway, and escaping from endosomal entrapment, while the cellular uptake of CHL-CBA-pDNA occurs via clathrin-and caveolae-independent mechanism.展开更多
The number of AgNORs in the nucleolar organizer region was studied quantitativelyby one-step silver colloid technique in 6 samples obtained from normal bladder tissue,9 ofchronic cystitis and 56 of transitional cell c...The number of AgNORs in the nucleolar organizer region was studied quantitativelyby one-step silver colloid technique in 6 samples obtained from normal bladder tissue,9 ofchronic cystitis and 56 of transitional cell carcinoma of bladder.The results revealed that meannumber of AgNORs per nucleus was not statistically different between normal bladder tissueand tissue from chronic cystitis,while there was a significant difference between normal or in-flammatory tissue and malignant tisssue on the one hand and between various grades of bladdertumor on the other.The results also indicated that mean number of AgNORs per nucleus wasclosely related to the prognosis of bladder tumor.So it is suggested that AgNOR counting bythe silver stain technique might play a role in the differenciation of benign and malignant lesionsand in grading and prognosis in bladder tumors.展开更多
Pollen development and floral morphology of Populus pseudo-simonii were investigated by stain-squashing and anatomical techniques. It took approximately 16 days for the pollen to develop from pollen mother cells to ma...Pollen development and floral morphology of Populus pseudo-simonii were investigated by stain-squashing and anatomical techniques. It took approximately 16 days for the pollen to develop from pollen mother cells to mature pollen in the green-house. Meiosis of pollen mother cells was regularly applied and completed by a process of simultaneous cytokinesis. Pollen development was considerably asynchronous. The meiotic division was initiated at the bulgy middle position of the flower bud and proceeded towards the tip and base of the bud. The number and size of the nucleoli varied during pollen development and at most eight nucleoli formed in each daughter nucleus at the meiotic telophase, suggesting a paleopolyploid origin of the genus Populus. An association between floral morphology and pollen development was found and the ratio of width to length of flower buds or catkins presented an S-shaped curve related to pollen development as a function of time. The investigation on the pollen development and floral morphology ofP. pseudo-simonii is important for further cross breeding programs of the section Tacamahaca.展开更多
Inspired by the first lustrum of the Club Positioning Matrix (CPM) for professional Dutch soccer teams, we model the interaction between soccer teams and their potential fans as a cooperative cost game based on the an...Inspired by the first lustrum of the Club Positioning Matrix (CPM) for professional Dutch soccer teams, we model the interaction between soccer teams and their potential fans as a cooperative cost game based on the annual voluntary sponsorships of fans in order to validate their fan registration in a central database. We introduce a natural cost allocation to the soccer teams, based in a natural manner on the sponsorships of fans. The game theoretic approach is twofold. On the one hand, an appropriate cost game called “fan data cost game” is developed and on the other, it is shown that the former natural cost allocation agrees with the solution concept called “nucleolus” of the fan data cost game.展开更多
By the methods of quantitative cytophotometry, we have identified the changes in the nucleus and of some intranuclear compartments in the early stages of infection with encephalomyocarditis virus (EMCV). They can be c...By the methods of quantitative cytophotometry, we have identified the changes in the nucleus and of some intranuclear compartments in the early stages of infection with encephalomyocarditis virus (EMCV). They can be characterized as early 1 - 2 hours post infection (hpi) and temporary increase (duration about 1 hour) in the content of the acidic proteins of the nucleolus, changing their decline to the control values. Then (after 1 - 2 hours) follows an increase in RNA content of nucleoli to 4 hours post infection (the process takes about 2 hours). The increase in RNA content in nucleoli is in approximately the same time (slightly behind) with the activation of PML bodies (2 - 4 hpi). Then, the RNA content in nucleoli decreased to the control values, while simultaneously decreasing activity of PML bodies (ranging from 5 - 6 hpi). The early stages of infection EMCV are also characterized by the tendency to increase in the size of the nuclei of infected cells, and preserve at a later time. Then there is an increase in RNA content in the nucleus, roughly coinciding with the increased content of RNA in the nucleoli.展开更多
文摘The effects of different concentrations of cadmium chloride ranging from 0.5 to 20 ppm on the nucleolus in root tip cells of Allium cepa were studied using the silver staining technique. The results indicated that after the treatment with Cd ̄(2+),different changes in nucleolar morphology appeared. The nucleolar material was extruded from the nucleus into the cytoplasm,and the nucleoli at mitotic metaphase did not disappear. Apparently,cadmium showed a specific effects on the nucleoli in root tip cells of Allium cepa. The possible mechanism behind this phenomenon is also briefly discussed.
文摘In our conversation with Prof.CHEN Lingling on the"dark mat ter"in the genome,namely the non-coding RNAs,we got to know two classes of long non-coding RNAs(lncRNAs)in close association with Prader-Willi syndrome(PWS).Each with a snoRNA cap on its either end,they fall in the sno-lncRNA family,a group of lncRNAs identified by CHEN’s group in their earlier research.Here we are meeting another member of the family,SLERT,a rescuer
基金the Shenzhen Science and Technology Research and Development Funds(No.JCYJ20190806155409104)National Natural Science Foundation of China(Nos.52150222,21672130 and 52073163)+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110356)the Qilu Young Scholars Program of Shandong University.
文摘Mitochondrial damage is closely related to the occurrence of many diseases.However,accurate monitoring and reporting of mitochondrial damage are not easy.Here,we developed a small molecule fluorescent probe named CB-Cl,which has splendid spectral properties(large Stokes shift,strong affinity for RNA,etc.)and excellent targeting ability to intracellular mitochondria.After mitochondria were damaged by external stimuli,CB-Cl would light up the nucleolus as a signal reporter.The cascade imaging of mitochondria and nucleolus using CB-Cl can monitor and visualize the mitochondrial status in living cells in real-time.Based on the above advantages,the probe CB-Cl has reference significance for the related research of mitochondrial damage and the prevention and treatment of related diseases.
文摘Purpose:The collaboration relationships between innovation actors at a geographic level may be considered as grouping two separate layers,the domestic and the foreign.At the level of each layer,the relationships and the actors involved constitute a Triple Helix game.The paper distinguished three levels of analysis:the global grouping together all actors,the domestic grouping together domestic actors,and the foreign related to only actors from partner countries.Design/methodology/approach:Bibliographic records data from the Web of Science for South Korea and West Africa breakdown per innovation actors and distinguishing domestic and international collaboration are analyzed with game theory.The core,the Shapley value,and the nucleolus are computed at the three levels to measure the synergy between actors.Findings:The synergy operates more in South Korea than in West Africa;the government is more present in West Africa than in South Korea;domestic actors create more synergy in South Korea,but foreign more in West Africa;South Korea can consume all the foreign synergy,which is not the case of West Africa.Research limitations:Research data are limited to publication records;techniques and methods used may be extended to other research outputs.Practical implications:West African governments should increase their investment in science,technology,and innovation to benefit more from the synergy their innovation actors contributed at the foreign level.However,the results of the current study may not be sufficient to prove that greater investment will yield benefits from foreign synergies.Originality/value:This paper uses game theory to assess innovation systems by computing the contribution of foreign actors to knowledge production at an area level.It proposes an indicator to this end.
文摘We observed the ultrastructure of nucleolus in rat liver cells by conventional electron microscopy, and employed cytochemistry NAMA-Ur DNA specific stain method to analyze the distribution and position of nucleolar DNA in situ. The results showed that nucleolar DNA of rat liver cells comes from nucleolus-associated chromatin, and continuously extends in the dense fibrillar component (DFC) of nucleolus, localizes at the periphery of fibrillar center (FC) and in DFC. Furthermore, by employing anti-DNA/RNA hybrid antibodies, we directly and selectively labeled transcription sites of rRNA genes and testified that localization of transcription sites not only to DFC but also to the periphery of FC.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39770367).
文摘The location and configuration of nucleolar DNA have not been determined for a long time. In this paper, we have observed the nucleolar infrastructure and the character of nucleolar DNA in Allium cepa cells by conventional electron microscopy and the cytochemical NAMA-Ur DNA specific staining method. Furthermore, we have properly improved the NAMA-Ur method so as to analyze the location and configuration of nucleolar DNA in situ. Our results indicated that the nucleolar DNA in Allium cepa cells is mainly located at the border between fibrillar centers and dense fibribllar component, especially distributed in the configuration of encircling the fibrillar centers.
基金part of the Dutch Research Council(NWO)Building Blocks of Lite programme(grant number 737.016.007).
文摘Microalgae are used in food and feed,and they are considered a potential feedstock for sustainably pro-duced chemicals and biofuel.However,production of microalgal-derived chemicals is not yet economically feasible.Genetic engineering could bridge the gap to industrial application and facilitate the production of novel products from microalgae.Here,we report the discovery of a novel gene expression system in the oleaginous microalga Nannochloropsis that exploits the highly efficient transcriptional activity of RNA po-lymerase I and an internal ribosome entry site for translation.We identified the nucleolus as a genomic safe harbor for Pol I transcription and used it to construct transformant strains with consistently strong trans-gene expression.The new expression system provides an outstanding tool for genetic and metabolic en-gineering of microalgae and thus will probably make substantial contributions to microalgal research.
文摘Nucleolus organizer regions (Nor loci) of a range of Chinese wheat landraces and cultivars (Triticum aestivum L. em Thell.) were analysed using genomic DNA extracted from leaves. Only two allelic variants of the Nor-B1 locus were found on chromosome 1B (Nor-B1a and Nor-B1g), while Nor-B1g was probably introduced from North America in the early 1960s. The even more recent introduction of the rye allele Nor-R1 in the early 1980s was also revealed. Eight allelic variants of the Nor-B2 locus on chromosome 6B (Nor-B2a, b, d, f, h, o, p and s) were identified. A Chinese origin for the a, d, f, o, p and s alkies is evident although the d allele was successfully introduced into Australian wheats in the early 1900s. Nor-B2h and Nor-B2b are again very recent introductions into Chinese wheat breeding programs, the former from CIMMYT wheats and the latter in association with the introduction of the 1RS/1BL translocation from Europe. On the basis of the presence of different combinations of Nor-B1 and Nor-B2
文摘Nucleolus is the most prominent subnuclear structure, which performs a wide variety of functions in the eukaryotic cellular processes. In order to understand the structural and functional role of the nucleoli in bovine cells, we analyzed the proteomic composition of the bovine nucleoli. The nucleoli were isolated from Madin Darby bovine kidney cells and subjected to proteomic analysis by LC-MS/MS after fractionation by SDS-PAGE and strong cation exchange chromatography. Analysis of the data using the Mascot database search and the GPM database search identified 311 proteins in the bovine nucleoli, which contained 22 proteins previously not identified in the proteomic analysis of human nucleoli. Analysis of the identified proteins using the GoMiner software suggested that the bovine nucleoli contained proteins involved in ribosomal biogenesis, cell cycle control, transcriptional, translational and post-translational regulation, transport, and structural organization.
基金the National Key R&D Program of China and the Natural Science Foundation of China in the order of 2018YFA0800502,2017YFA0504501,31330050.
文摘The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,cellular senescence,and stress response.The protein composition of the nucleolus changes dynamically through protein turnover to meet the needs of cellular activities or stress responses.Recent studies have identified a nucleolus-localized protein degradation pathway in zebrafish and humans,namely the Def-CAPN3 pathway,which is essential to ribosome production and cell-cycle progression,by controlling the turnover of multiple substrates(e.g.,ribosomal small-subunit[SSU]processome component Mpp10,transcription factor p53,check-point proteins Chk1 and Wee1).This pathway relies on the Ca2þ-dependent cysteine proteinase CAPN3 and is independent of the ubiquitin-mediated proteasome pathway.CAPN3 is recruited by nucleolar protein Def from cytoplasm to nucleolus,where it proteolyzes its substrates which harbor a CAPN3 recognition-motif.Def depletion leads to the exclusion of CAPN3 and accumulation of p53,Wee1,Chk1,and Mpp10 in the nucleolus that result in cell-cycle arrest and rRNA processing abnormality.Here,we summarize the discovery of the Def-CAPN3 pathway and propose its biological role in cell-cycle control and ribosome biogenesis.
文摘Our conventional EM observations indicate that the nucleolus of Allium cepa is composedof the fibrillar centre (FC), fibrillar component (F) and granular region (G). FC is an elec-tron-lucid zone which contains condensed or loosened chromatin. F is a circular, highly elec-tron-dense component which surrounds FC and consists of compact fibrils. EM autoradiographic(EM ARG) studies with ~3H- UdR reveal that the synthesis of ribosomal RNA (rRNA) takesplace in F. G is situated around F and composed of granules about 25 to 30 nm in diameter.EM ARG studies with ~3H- TdR demonstrate that silver grains are predominantly located in Gof the nucleolar periphery and the region of the nucleolus-associated chromatin. In addition,~3H- TdR labels are also present, but with a much lower frequency, in FC. F and G of the nu-cleolar interior. According to the distribution and sphere of silver grains in different compo-nents of the nucleolus, we suggest that the replication sites of ribosomal DNA (rDNA) aremainly located
基金This work was supported by the National Key Research and Development Program of China(No.2018YFC0310900)the National Natural Science Foundation of China grants(No.31270830,21572038,21877016 to Y.D,No.31671386 to Q.H,81972621 to W.J)+1 种基金the Development Fund for Shanghai Talents,Fund of State Key Laboratory of Bioorganic and Natural Products Chemistry,Fund of State Key Laboratory of Drug Research,Chinese Academy of Science(No.SIMM1601KF-08)Fudan University Graduate Student Research Grant.
文摘The CRISPR/Cas9 system,originally derived from the prokaryotic adaptive immune system,has been developed as efficient genome editing tools.It enables precise gene manipulation on chromosomal DNA through the specific binding of programmable sgRNA to target DNA,and the Cas9 protein,which has endonuclease activity,will cut a double strand break at specific locus.However,Cas9 is a foreign protein in mammalian cells,and the potential risks associated with its introduction into mammalian cells are not fully understood.In this study,we performed pull-down and mass spectrometry(MS)analysis of Streptococcus pyogenes Cas9(SpyCas9)interacting proteins in HEK293T cells and showed that the majority of Cas9-associated proteins identified by MS were localized in the nucleolus.Interestingly,we further discovered that the Cas9 protein contains a sequence encoding a nucleolus detention signal(NoDS).Compared with wild-type(WT)Cas9,NoDS-mutated variants of Cas9(mCas9)are less stable,although their gene editing activity is minimally affected.Overexpression of WT Cas9,but not mCas9,causes general effects on transcription and protein translation in the host cell.Overall,identification of NoDS in Cas9 will improve the understanding of Cas9's biological function in vivo,and the removal of NoDS in Cas9 may enhance its safety for future clinical use.
文摘The effects of different concentrations of manganous sulphate on root growth,cell division, chromosome and nucleus morphplogy and nucleoli in root tip-cells of Allium cepa L. were studied. The concentrations of manganous sulphate used were 10-7,10-6,10-5 ,10-4,10-3, 10-2 and 10-1mol/L. The results indicated that manganese had a stimulatory effect on the root growth at lower concentrations (10-7 to 10-4mol/L). With increasing the concentration of Mn (10-3 to 10-1mol/L) and duration of treatment,manganese inhibited root growth and cell division, and had toxic effects on chromosomes,nuclei and nucleoli. Manganese Could induce mitotic irregularities,comprising c-mitosis,anaphase bridges and chromosome stickiness. The nuclei became irregular in shape and many micronuclei were scattered in the cytoplasm. Some similar silver-stained particulate materials were found scattered in the nucleus in root tip cells. The possible mechanism behind these phenomena is also briefly discussed.
基金supported by National Natural Science Foundation of China (Grant no. 81373335)
文摘Guanidinylated bioresponsive poly(amido amine)s polymers, CAR-CBA and CHL-CBA, weresynthesized by Michael-type addition reaction between guanidine hydrochloride(CAR) orchlorhexidine(CHL) and N,N-cystaminebisacrylamide(CBA). Previous studies have shownthat both polymers had high transfection efficiencies as gene delivery carriers. In this study,we investigated the nucleolus localization abilities and cellular internalization pathways ofthese two polymers in gene delivery. Each polymer condensed plasmid DNA(p DNA) andformed nanoparticle complexes, and then their transfection studies were performed inMCF-7 cells. Both complexes were found enriched in nucleolus after cellular transfection,and their transfection efficiencies were significantly improved when transfection was per-formed on MCF-7 cells arrested at M phase. The transfection efficiency of CAR-CBA-pDNAwas inhibited by chlorpromazine, and cell endosomes were disrupted after being exposedto CAR-CBA-pDNA. In regards to CHL-CBA-pDNA, its transfection efficiency was not affected by three types of endocytosis inhibitors used in the study, and CHL-CBA-pDNA showed no effect on endosomes. Cellular lactate dehydrogenase release and membrane morphology were changed after cells were transfected by the two complexes. The results indicated that both CAR-CBA and CHL-CBA polymers demonstrated good nucleolus localization abilities. It was beneficial for transfection when cells were arrested at M phase. CAR-CBA-pDNA cellular internalization was involved with clathrin-mediated endocytosis pathway, and escaping from endosomal entrapment, while the cellular uptake of CHL-CBA-pDNA occurs via clathrin-and caveolae-independent mechanism.
文摘The number of AgNORs in the nucleolar organizer region was studied quantitativelyby one-step silver colloid technique in 6 samples obtained from normal bladder tissue,9 ofchronic cystitis and 56 of transitional cell carcinoma of bladder.The results revealed that meannumber of AgNORs per nucleus was not statistically different between normal bladder tissueand tissue from chronic cystitis,while there was a significant difference between normal or in-flammatory tissue and malignant tisssue on the one hand and between various grades of bladdertumor on the other.The results also indicated that mean number of AgNORs per nucleus wasclosely related to the prognosis of bladder tumor.So it is suggested that AgNOR counting bythe silver stain technique might play a role in the differenciation of benign and malignant lesionsand in grading and prognosis in bladder tumors.
基金supported by the National Natural Science Foundation of China (Grant No. 30671708)the National Key Technology R&D Programme of the 11th Five-Year Plan of China (Grant No. 2006BAD32B01)
文摘Pollen development and floral morphology of Populus pseudo-simonii were investigated by stain-squashing and anatomical techniques. It took approximately 16 days for the pollen to develop from pollen mother cells to mature pollen in the green-house. Meiosis of pollen mother cells was regularly applied and completed by a process of simultaneous cytokinesis. Pollen development was considerably asynchronous. The meiotic division was initiated at the bulgy middle position of the flower bud and proceeded towards the tip and base of the bud. The number and size of the nucleoli varied during pollen development and at most eight nucleoli formed in each daughter nucleus at the meiotic telophase, suggesting a paleopolyploid origin of the genus Populus. An association between floral morphology and pollen development was found and the ratio of width to length of flower buds or catkins presented an S-shaped curve related to pollen development as a function of time. The investigation on the pollen development and floral morphology ofP. pseudo-simonii is important for further cross breeding programs of the section Tacamahaca.
文摘Inspired by the first lustrum of the Club Positioning Matrix (CPM) for professional Dutch soccer teams, we model the interaction between soccer teams and their potential fans as a cooperative cost game based on the annual voluntary sponsorships of fans in order to validate their fan registration in a central database. We introduce a natural cost allocation to the soccer teams, based in a natural manner on the sponsorships of fans. The game theoretic approach is twofold. On the one hand, an appropriate cost game called “fan data cost game” is developed and on the other, it is shown that the former natural cost allocation agrees with the solution concept called “nucleolus” of the fan data cost game.
文摘By the methods of quantitative cytophotometry, we have identified the changes in the nucleus and of some intranuclear compartments in the early stages of infection with encephalomyocarditis virus (EMCV). They can be characterized as early 1 - 2 hours post infection (hpi) and temporary increase (duration about 1 hour) in the content of the acidic proteins of the nucleolus, changing their decline to the control values. Then (after 1 - 2 hours) follows an increase in RNA content of nucleoli to 4 hours post infection (the process takes about 2 hours). The increase in RNA content in nucleoli is in approximately the same time (slightly behind) with the activation of PML bodies (2 - 4 hpi). Then, the RNA content in nucleoli decreased to the control values, while simultaneously decreasing activity of PML bodies (ranging from 5 - 6 hpi). The early stages of infection EMCV are also characterized by the tendency to increase in the size of the nuclei of infected cells, and preserve at a later time. Then there is an increase in RNA content in the nucleus, roughly coinciding with the increased content of RNA in the nucleoli.