Optimized silicon fertilization regime weakens cadmium translocation and increases its biotransformation in rice tissues

In acidic paddy fields of South China,rice(Oryza sativa L.)faces the dual challenges of cadmium(Cd)toxicity and silicon(Si)deficiency.Although previous studies have highlighted the functions of Si application timing and strategies in mitigating Cd-stressed rice,the precise mechanisms underlying the health restoration of Cd-toxic rice and the assurance of grain safety remain elusive.This study explored Cd translocation and detoxification in the shoots of rice regulated by various Si fertilization regimes:Si(T)(all Si added before transplanting),Si(J)(all Si added at jointing),and Si(TJ)(half Si added both before transplanting and at jointing).The findings revealed that the regime of Si(TJ)was more beneficial to rice health and grain safety than Si(T)and Si(J).The osmotic regulators such as proline,soluble sugars,and soluble proteins were significantly boosted by Si(TJ)compared to other Si treatments,and which enhanced membrane integrity,balanced intracellular pH,and increased Cd tolerance of rice.Furthermore,Si(TJ)was more effective than Si(T)and Si(J)on the Cd sequestration in the cell wall,Cd bio-passivation,and the down-regulated expression of the Cd transport genes.The concentrations of Cd in the xylem and phloem treated with Si(TJ)were reduced significantly.Additionally,Si(TJ)facilitated much more Cd bound with the outer layer proteins of grains,and promoted Cd chelation and complexation by phytic acid,phenolics,and flavonoids.Overall,Si(TJ)outperformed Si(T)and Si(J)in harmonizing the phycological processes,inhibiting Cd translocation,and enhancing Cd detoxification in rice plant.Thereby the split Si application strategy offers potential for reducing Cd toxicity in rice grain.

Effects of Slow-release Nitrogen on Dry Matter Accumulation,Translocation and Yield of Summer Maize

[Objectives]This study was conducted to investigate the effects of slow-release nitrogen fertilizer on dry matter accumulation and translocation of summer maize.[Methods]With Zhoudan 9 as the test variety,six different treatment were set up:blank control(CK1),slow-release urea 75 kg/hm^(2)(C1),slow-release urea 150 kg/hm^(2)(C2),slow-release urea 225 kg/hm^(2)(C3),slow-release urea 300 kg/hm^(2)(C4)and ordinary urea 300 kg/hm^(2)(CK2),to study the change law of dry matter accumulation and translocation in summer maize.[Results]Treatment slow-release urea 225 kg/hm^(2)(C4)showed summer maize yield,dry matter translocation between organs,grain contribution rate and proportion of grain dry matter in the full ripe stage higher than other treatments.Considering the weight loss and cost factors,slow-release urea 225 kg/hm^(2)(C3)could be recommended as the fertilizing amount for summer maize.[Conclusions]This study provides theoretical reference for rational selection of fertilizers for reducing fertilizer application and increasing fertilizer efficiency,and for production of summer maize in Shajiang black soil region.

Increased 5-hydroxymethylcytosine and Ten-eleven Translocation Protein Expression in Ultraviolet B-irradiated HaCaT Cells

Background： DNA hydroxymethylation refers to a chemical modification process in which 5-methylcytosine （5mC） is catalyzed to 5-hydroxymethylcytosine （5hmC） by ten-eleven translocation （TET） family proteins. Recent studies have revealed that aberrant TETs expression or 5hmC level may play important roles in the occurrence and development of various pathological and physiological processes including cancer and aging. This study aimed to explore the relation between aberrant DNA hydroxymethylation with skin photoaging and to investigate the levels of TETs, 5mC, and 5hmC expression 24 h after 40 mJ/cm^2 and 80 mJ/cm^2 doses of ultraviolet B （UVB） irradiation to HaCaT cells. Methods： To explore whether aberrant DNA hydroxymethylation is also related to skin photoaging, 40 mJ/cm^2 and 80 mJ/cm^2 doses of UVB were chosen to treat keratinocytes （HaCaT cells）. After 24 h of UVB irradiation, 5mC and 5hmC levels were determined by immunohistochemistry （IHC） and immunofluorescence （IF）, and at the same time, the expression levels of matrix metalloproteinase 1 （MMP-1） and TETs were assessed by reverse transcription-polymerase chain reaction or Western blot analysis. Results： After 40 mJ/cm^2 and 80 mJ/cm^2 doses of UVB exposure, both IHC and IF results showed that 5hmC levels increased significantly, while the 5mC levels did not exhibit significant changes in HaCaT cells, compared with HaCat cells without UVB exposure. Moreover, compared with HaCat cells without UVB exposure, the levels ofTET1, TET2, and TET3 mRNA and protein expression were significantly upregulated （mRNA： P = 0.0022 and 0.0043 for TET1; all P 〈 0.0001 for TET2; all P = 0.0006 for TET3; protein： P = 0.0012 and 0.0006 tbr TET 1 ; all P = 0.0022 for TET2; and all P = 0.0002 for TET3）, and the levels of MMP- 1 mRNA expression increased dose dependently in 40 mJ/cm^2 and 80 mJ/cm^2 UVB-irradiated groups. Conclusion： UVB radiation could cause increased 5hmC and TET expression, which might become a novel biomarker in UVB-related skin aging.

Multiple Functions of Ten-eleven Translocation 1 during Tumorigenesis

Objective： Aberrant expression of ten-eleven translocation 1 （TET1） plays a critical role in tumor development and progression. We systematically summarized the latest research progress on the role and mechanisms of TET1 in cancer biology. Data Sources： Relevant articles published in English from 1980 to April 2016 were selected from the PubMed database. Tile terms ＂＇ten-eleven translocation 1,＂ ＂＇SmC,＂ ＇5hmC,＂ ＇microRNA,＇＂ ＂hypoxia,＂ and ＂＇embryonic stem cell＇＂ were used tbr the search. Study Selection： Articles focusing on the role and mechanism ofTETI in tumor were reviewed, including clinical and basic research articles. Results： TET proteins, the key enzymes converting 5-methylcytosine to 5-hydroxymethylcytosine, play vital roles in DNA demethylation regulation. Recent studies have shown that loss of TETI is associated with tumorigenesis and can be used as a potential biomarker for cancer therapy, which indicates that TETI serves as tumor suppressor gene. Moreover, besides its dioxygenase activity, TET1 could induce epithelial-mesenchymal transition and act as a coactivator to regulate gene transcription, such as developmental regulator in embryonic stem cells （ESCs） and hypoxia-responsive gene in cancer. The regulation of TETl is also correlated with microRNA in a posttranscriptional modification process. Hence, it is complex but critical to coaprehend the mechanisms of TETI in the biology of ESCs and cancer. Conclusions： TET I not only serves as a demethylation enzyme but also plays multiple roles during tumorigenesis and progression. More studies should be carried out to elucidate the exact mechanisms of TETI and its associations with cancer betbre considering it as a therapeutic tool.

Development and characterization of a novel common wheat–Mexico Rye T1DL·1RS translocation line with stripe rust and powdery mildew resistance

Rye(Secale cereale L., 2n=2x=14, RR) is a significant genetic resource for improving common wheat because of its resistance to multiple diseases and abiotic-stress tolerant traits. The 1RS chromosome from the German cultivated rye variety Petkus is critical in wheat breeding. However, its weakened disease resistance highlights the need to identify new resources. In the present study, a novel derived line called D27 was developed from common wheat and Mexico Rye.Cytological observations characterized the karyotype of D27 as 2n=42=21 Ⅱ. Genomic in situ hybridization indicated that a pair of whole-arm translocated Mexico Rye chromosomes were inherited typically in the mitotic and meiosis stages of D27. Experiments using fluorescence in situ hybridization(FISH) and gliadin electrophoresis showed that D27 lacked wheat 1DS chromosomes. They were replaced by 1RS chromosomes of Mexico Rye, supported by wheat simple-sequence repeat markers, rye sequence characterized amplified region markers, and wheat 40K SNP array analysis.The wheat 1DS chromosomes could not be detected by molecular markers and wheat SNP array, but the presence of rye 1RS chromosomes was confirmed. Agronomic trait assessments indicated that D27 had a higher tiller number and enhanced stripe rust and powdery mildew resistance. In addition, dough properties analysis showed that replacing 1DS led to higher viscosity and lower dough elasticity in D27, which was beneficial for cake making. In conclusion, the novel cytogenetically stable common wheat–Mexico Rye T1DL·1RS translocation line D27 offers excellent potential as outstanding germplasm in wheat breeding programs focusing on disease resistance and yield improvement. Additionally,it can be valuable for researching the rye 1RS chromosome’s genetic diversity.

Translocation and Distribution of Carbon-Nitrogen in Relation to Rice Yield and Grain Quality as Affected by High Temperature at Early Panicle Initiation Stage

Due to climate change, extreme heat stress events have become more frequent, adversely affecting rice yield and grain quality. The accumulation and translocation of dry matter and nitrogen substances are essential for rice yield and grain quality. To assess the impact of high temperature stress(HTS) at the early panicle initiation(EPI) stage on the accumulation, transportation, and distribution of dry matter and nitrogen substances in various organs of rice, as well as the resulting effects on rice yield and grain quality, pot experiments were conducted using an indica rice cultivar Yangdao 6(YD6) and a japonica rice cultivar Jinxiangyu 1(JXY1) under both normal temperature(32 ℃/26 ℃) and high temperature(38 ℃/29 ℃) conditions. The results indicated that exposure to HTS at the EPI stage significantly decreased rice yield by reducing spikelet number per panicle, grain-filling rate, and grain weight. However, it improved the nutritional quality of rice grains by increasing protein and amylose contents. The reduction in nitrogen and dry matter accumulation accounted for the changes in spikelet number per panicle, grain-filling rate, and grain size. Under HTS, the decrease in nitrogen accumulation accompanied by the reduction in dry matter may be due to the down-regulation of leaf net photosynthesis and senescence, as evidenced by the decrease in nitrogen content. Furthermore, the decrease in sink size limited the translocation of dry matter and nitrogen substances to grains, which was closely related to the reduction in grain weight and the deterioration of grain quality. These findings significantly contribute to our understanding of the mechanisms of HTS on grain yield and quality formation from the perspective of dry matter and nitrogen accumulation and translocation. Further efforts are needed to improve the adaptability of rice varieties to climate change in the near future.

Fast tracking alien gene discovery by molecular markers in a late flowering Chinese cabbage-cabbage translocation line‘AT7–4'

Flowering time is an important agronomic trait of Chinese cabbage with late flowering being a primary breeding objective.In our previous work,we obtained Chinese cabbage-cabbage translocation lines that contained several beneficial cabbage genes.Cabbage-specific molecular markers show that these genes were coming from chromosome C01 of cabbage.In this study,we investigated the inheritance of flowering time in a couple of translocation lines and analyzed the transmission rate of molecular markers in the offspring.Consequently,we obtained the late flowering Chinese cabbage-cabbage translocation line‘AT7–4’in which the flowering time was later than that of‘85–1’by about 7 days under 4-week vernalization.Based on previous studies of the genomes of Chinese cabbage and cabbage,we located the cabbage-specific molecular markers that were closely linked at the top of the chromosome A01 in the F2mapping population generated by self-crossing F1s derived from a cross between the translocation line‘AT7–4’and Chinese cabbage‘14–36’.Five flowering-related genes in the alien fragment were found by functional annotation and their molecular markers were developed.This study lays the foundation for the future improvement of Chinese cabbage varieties using A-C translocation lines.

Molecular cytogenetic analyses of two new wheat-rye 6RL translocation lines with resistance to wheat powdery mildew

Rye(Secale cereale)is a valuable gene donor for wheat improvement,especially for its resistance to diseases.Developing rye-derived resistance sources is important for wheat breeding.In the present study,two wheat-rye derivatives,designated JS016 and JS110,were produced by crossing common wheat cultivar Yangmai 23 with Pakistani rye accession W2A.Using sequential genomic in situ hybridization(GISH)and multicolor fluorescence in situ hybridization(mc-FISH),JS016 and JS110 were identified as a T6BS.6RL translocation line and a T6BS.6BL6RL translocation line,respectively.Ten newly 6RL chromosome arm-specific markers were developed and used to confirm the 6RL translocation.The wheat 55K single-nucleotide polymorphism(SNP)array further verified the molecular cytogenetic identification results above and clarified their breakpoints at 430.9 and 523.0 Mb of chromosome 6B in JS016 and JS110,respectively.Resistance spectrum and allelism test demonstrated that JS016 and JS110 possessed novel powdery mildew resistance gene(s)that was derived from the 6RL translocation but differed from Pm20.Moreover,JS016 and JS110 had better agronomic traits than the previously reported 6RL translocation line carrying Pm20.To efficiently transfer and detect the 6RL translocation from JS016 and JS110,one 6RL-specific Kompetitive allele specific PCR(KASP)marker was developed and validated in high throughput marker-assisted selection(MAS).

Chromosome 5P of Agropyron cristatum induces chromosomal translocation by disturbing homologous chromosome pairing in a common wheat background

Wide hybridization is a strategy for broadening the genetic basis of wheat. Because an efficient method for inducing wheat–alien chromosome translocations will allow producing useful germplasm, it is desirable to discover new genes that induce chromosomal variation. In this study, chromosome 5P from A.cristatum was shown to induce many types of chromosomal structural variation in a common wheat background, including nonhomoeologous chromosome translocations, as revealed by genomic in situ hybridization, fluorescence in situ hybridization, and DNA marker analysis. Aberrant meiosis was associated with chromosomal structural variation, and aberrant meiotic behavior was observed in wheat–A.cristatum 5P monosomic and disomic addition lines, suggesting that the effect of chromosome 5P was independent of the number of chromosome 5P copies. Chromosome 5P disturbed homologous chromosome pairing at pachytene stage in a common wheat background, resulting in a high frequency of univalent formation and reduced crossing over. Thirteen genes involved in DNA repair or chromatin remodeling, including RAD52-like and MSH6 genes, were differentially expressed(upregulated) in wheat–A. cristatum 5P addition lines according to transcriptome analysis, implicating chromosome 5P in the process of meiotic double-strand break repair. These findings provide a new, efficient tool for inducing wheat–alien chromosome translocations and producing new germplasm.

Nonalcoholic fatty liver disease aggravates acute pancreatitis through bacterial translocation and cholesterol metabolic dysregulation in the liver and pancreas in mice

Background:Nonalcoholic fatty liver disease(NAFLD)is an independent risk factor for severe acute pancreatitis(AP).The underlying mechanism remains unclear.We sought to determine how bacterial translocation and cholesterol metabolism in the liver and pancreas affect the severity of AP in NAFLD mice.Methods:C57BL/6N mice were fed on a high-fat diet(HFD)to generate the NAFLD model,and mice in the control group were provided with a normal diet(ND).After being anesthetized with ketamine/xylazine,mice got a retrograde infusion of taurocholic acid sodium into the pancreatic duct to induce AP,and sham operation(SO)was used as control.Serum amylase and Schmidt’s pathological score system were used to evaluate AP severity.Bacterial loads,total cholesterol level,and cholesterol metabolic-associated molecules[low-density lipoprotein receptor(LDLR)and ATP-binding cassette transporter A1(ABCA1)]were analyzed in the liver and pancreas.Results:Compared with the ND-AP group,mice in the HFD-AP group had severer pancreatitis,manifested with higher serum amylase levels and higher AP pathologic scores,especially the inflammation and hemorrhage scores.Compared with the HFD-SO group and ND-AP group,bacterial loads in the liver and pancreas were significantly higher in the HFD-AP group.Mice in the HFD-AP group showed a decreased LDLR expression and an increased ABCA1 expression in the pancreas,although there was no significant difference in pancreas total cholesterol between the HFD-AP group and the ND-AP group.Conclusions:NAFLD aggravates AP via increasing bacterial translocation in the liver and pancreas and affecting pancreas cholesterol metabolism in mice.

Ten-eleven translocation-2 affects the fate of cells and has therapeutic potential in digestive tumors

Ten-eleven translocation(TET)methylcytosine dioxygenases catalyze the oxidative reactions of 5-methylcytosine(5-mC)to 5-hydroxymethylcytosine(5-hmC),5-formylcytosine(5-fC),and 5-carboxylcytosine(5-caC),which are intermediate steps during DNA demethylation.It is reported that somatic mutations of TET2 gene are identified in a variety of human tumors,especially in hematological malignancies.The tendency and mechanism of cellular differentiation in different systems are affected by TET2 via regulation of associated gene expression or maintenance of demethylated state.TET2 acts as a critical driver of tumorigenesis through the conversion of 5-mC to 5-hmC and successive oxidation products.Sometimes,it requires special interactions and cofactors.Here,we reviewed recent advances in understanding the function of TET2 proteins in regulating cell differentiation,and its role in various tumors focusing on several digestive cancers.

Genetic effects of Agropyron cristatum 2P chromosome translocation fragments in a wheat background

Agropyron cristatum(2n=4x=28,PPPP)is a wild relative of common wheat which contains a large number of desirable genes that can be exploited for wheat improvement.Wheat–A.cristatum 2P alien translocation lines exhibit many desirable traits,such as small flag leaves,a high spikelet number and density,and a compact plant type.An agronomic trait evaluation and a genetic analysis were carried out on translocation lines and backcross populations of these lines carrying different translocation fragments.The results showed that a translocation fragment from 2PT-3(2PL)reduced the length of the flag leaves,while translocation fragments from 2PT-3(2PL)and 2PT-5(2PL(0.60–1.00))reduced the width of the flag leaves.A translocation fragment from 2PT-13(2PS(0.18–0.36))increased the length and area of the flag leaves.Translocation fragments from 2PT-3(2PL)and 2PT-8(2PL(0.86–1.00))increased the density of spikelets.Translocation fragments from 2PT-7(2PL(0.00–0.09)),2PT-8(2PL(0.86–1.00)),2PT-10(2PS),and 2PT-13(2PS(0.18–0.36))reduced plant height.This study provides a scientific basis for the effective utilization of wheat–A.cristatum translocation lines.

Effect of Alternate Bearing Phenomenon and Boron Foliar Application on Nitrogen-15 Uptake,Translocation and Distribution in Mango Tree(cv.Zebda)

The objectives of this investigation are to study nitrogen uptake,translocation,accumulation and distribution in mango tree organs using labeled nitrogen(^(15)N)and to understand the mechanism of boron action in increasing fruit yield in the off-year.A field experiment was conducted using fifteen-year-old mango trees(cv.Zebda)grown at Al Malak Valley Farm,El-Sharkeya Governorate-Egypt.Treatments included the application of(^(15)NH4)2SO4,“in the on-year”,at a rate of 50 g nitrogen/tree through the stem injection technique.While boron was sprayed on the same trees“in the off-year”at the following rates:0.0(control),250 and 500 mg·L^(-1).The authors hypothesize that boron and nitrogen act synergistically to increase mango fruit yield in the off-year.Results indicated that the highest ^(15)N uptake and accumulation in the on and off-years was observed in the upper(young leaves).When boron was applied at 250 mg·L^(-1),in the off-year,the upper(young leaves)recorded the highest ^(15)N uptake and accumulation(%^(15)Ndff=13.93)relative to the other two leaf categories and those of the on-year.In the on-year fruit accumulated higher ^(15)N than leaf or bud.In the off-year,bud exhibited the highest ^(15)N accumulation without boron application,while leaves exhibited the highest ^(15)N with boron application.The highest%^(15)Ndff in all tree organs was observed at 250 mg·L^(-1) boron rate.Boron increased nitrogen uptake,translocation and accumulation in mango tree organs.A synergistic relationship was observed between boron and nitrogen which led to an increase in fruit yield in the off-year.

Identification of Triticum aestivum-Haynaldia villosa Translocation Line T6BS·6BL-2VS

[Objective] The aim of experiment was to provide a new germplasm for wheat breeding by further using desirable genes in 2V chromosome of Haynaldia villosa.[Method] Through hybridization between common wheat(Triticum aestivum)-Haynaldia villosa disomic substitution line and common wheat Nonglin26-3C chromosome of Aegilops triuncialis disomic addition line,the analysis methods such as chromosome C-banding,genomic in situ hybridization and molecular marker technique were comprehensively applied and combined characters investigation.[Result] The wheat-Haynaldia villosa translocation line(T6BS·6BL-2VS)was selected from hybrid progenies to conduct characters investigation,which found some bristles on glume ridge of T6BS·6BL-2VS.[Conclusion] The translocation line induced by gametocidal chromosome was a small segment translocation line and the gene of bristle on glume ridge of Haynaldia villosa was located between the middle and the terminal of 2VS.

Fruit Photosynthesis and Assimilate Translocation and Partitioning: Their Characteristics and Role in Sugar Accumulation in Developing Citrus unshiu Fruit

Dynamics of dry- or fresh-weight of fruit, peel photosynthetic rate and chlorophyll content, and the characteristics of translocation and distribution of radiolabelled assimilates from leaf or fruit were examined in developing satsuma mandarin (Citrus unshiu Marc. cv. Miyagawa wase) fruit from primary stage of fruit enlargement up to fruit full ripe. Change in fruit photosynthetic rate was some what related to the change in the chlorophyll content of peel. Fruit photosynthetic rate markedly declined as chlorophyll degradation occurred in the peel. Before full ripe stage of the fruit, photosynthates produced by a 14C-fed leaf were mainly distributed to juice sacs even during periods when dry matter accumulation in peel was more rapid than that in juice sacs. At the full ripe stage, peel photosynthetic rate approached zero and peel became the major sink of leaf photosynthates. Most of the peel assimilates, however, remained in situ for up to 48 h after feeding 14CO 2 to the fruit, only a small portion being transported to other parts of fruit. The percentage of fruit photosynthates exported decreased with fruit development and ripening, but the peak rate of export to juice sacs amount to as high as 12%. The sugar content and dry weights of peel and juice sacs in shaded fruit were lower than that in the control fruit. These results show that peel assimilate was mainly consumed in peel respiration and growth and thus the dependence on leaf photosynthates decreased. Part of this assimiate was used in sugar accumulation in juice sacs of fruit.

Translocation and Distribution of Imidacloprid in Tobacco with Two Application Methods

[Objective] To compare the translocation and distribution of imidacloprid in tobacco with spray and root irrigation application methods. [Methods] Pot experiment in the greenhouse was carried out, and LC-MSMS was used to determine the con- tent of imidacloprid in different parts of tobacco plants （roots, stems, the upper, middle and lower leaves） at different time. [Results] The imidacloprid could be absorbed by root and could be transported to all parts of the tobacco plant after irrigating root, but the original deposition amount was larger and the transport efficiency was lower after spraying. [Conclusion] The translocation and distribution of imidacloprid by spraying was more uniform and the holding efficiency was better, but imidacloprid with root irrigation could act on leaf directly, and had better readily availability.

Polymorphisms of CMYA3 Gene in 13/17 Robertsonian Translocation Pigs

[Objective] The aim was to study the polymorphism of CMYA3 gene in the 148 pigs of hybrid offspring of 13/17 Robertsonian translocation pigs [2n = 37,rob （13;17）] intercrossing.[Method] PCR-RFLP method was adopted.[Result] A 507 bp fragment of CMYA3 gene was obtained by PCR amplification,and then amplification product by using restriction nuclease Bsh1236Ⅰ was detected by agarose gel electrophoresis.As a result,both alleles （A and B） of the loci were found in the population.The frequencies of allele A and B were 0.699 and 0.301.The genotype frequencies of AA,AB and BB were 0.615,0.169 and 0.216.The frequencies of allele A and genotype AA were significantly higher than allele B and genotype BB in populations.[Conclusion] The study will provide theoretical basis for molecular breeding and marker-assisted selection of 13/17 Robertsonian translocation pigs.

Meiotic Behavior of 1BL/1RS Translocation Chromosome and Alien Chromosome in Two Tri-genera Hybrids

The behavior of wheat-rye translocation chromosome and alien chromosome including Thinopyrum and Haynaldia chromosome at meiosis was investigated in two hybrids by fluorescence in situ hybridization (FISH). Misdivision of translocation chromosome at anaphase I and rye chromatin micronucleus at tetrad stage were observed, A plant with one normal 1BL/1RS translocation chromosome and one 1BL/1RS translocation chromosome deleted about 1/3 of rye chromosome arm in length was identified. One plant with wheat-Thinopyrum non-Robertson translocation chromosome was also detected in the F-2 population of Yi4212 x Yi4095. That could be the results of unequal misdivision of wheat-rye 1BL/1RS translocation chromosome and Thinopyrum chromosome during meiosis. No interaction between translocation chromosome and alien chromosome at meiosis was supported by the data of the distribution frequencies of translocation chromosome and Thinopyrum or Haynaldia chromosome in the progeny of two hybrids. The results may be useful to cultivate new germplasms with different length of rye 1R short arm and wheat-alien non-Robertson translocation tines under wheat background.

基因组Translocation排序问题的改进多项式算法

该文给出基因组 Translocation排序问题的一个改进多项式算法 .原算法所用存储空间为 O(n) ,时间复杂度为 O(n3) .文中改进算法仍采用 O(n)存储空间 ,时间复杂度为 O(n2 logn) .具体地 ,将计算 Translocation距离的时间复杂度由 O(n3)改进为 O(n2 ) ,将计算 Translocation序列的时间复杂度由 O(n3)改进为 O(n2 logn) .

Effect of Interaction upon Translocation of Confined Polymer Chain Through Nanopore

The effect of the interaction between nanopore and chain monomer on the translocation of a single polymer chain confined in a finite size square through an interacting nanopore to a large space has been studied by two-dimensional bond fluctuation model with Monte Carlo simulation. Results indicate that the free energy barrier before the successful translocation of the chain depends linearly on the chain length as well as the nanopore length for different pore-polymer interaction, and the attractive interaction reduces the free energy barrier, leading to the reduction of the average trapping time.