Mar 2007, Volume 2 Issue 1
    

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  • MicroRNAs and their role in viral infection
    MU Junjie, YAO Xue, CHEN Qimin, GENG Yunqi, QIAO Wentao
    2007, 2(1): 15-20. https://doi.org/10.1007/s11515-007-0002-x
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    Recently, a class of about 22 nucleotides (nt) small RNA has been discovered in many eukaryotes, termed microRNAs (miRNAs), which have a variety of functions. Many recent findings have demonstrated that viruses can also encode their own miRNAs. Meanwhile, other findings reveal a relationship between host miRNA and viral infection. These findings suggest a tight relationship between host and viral infection via miRNA pathway. This article introduces the miRNAs encoded by viruses and reviews the advances of the interaction of the mammalian host miRNAs and viral infection.
  • Advance on the production of polyhydroxyalkanoates by mixed cultures
    L? Yaoping
    2007, 2(1): 21-25. https://doi.org/10.1007/s11515-007-0003-9
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    Polyhydroxyalkanoates (PHAs) are the polymers of hydroxyalkanoates that accumulate as carbon/energy or reducing-power storage material in various microorganisms. PHAs have attracted considerable attention as biodegradable substitutes for conventional polymers. Until now, however, industrial production of PHAs has encountered only limited success. The main barrier to the replacement of synthetic plastics by PHAs has been the higher cost. The use of mixed cultures and renewable sources obtained from waste organic carbon can substantially decrease the cost of PHA and increase their market potential. This work reviews two main methods of PHA production by mixed cultures, anaerobic aerobic processing and aerobic transient feeding processing, and analyzed the metabolic and effective factors.
  • Characterization of melanin produced by a wild-type strain of Bacillus cereus
    ZHANG Jianping, CAI Jun, DENG Yinyue, CHEN Yuehua, REN Gaixin
    2007, 2(1): 26-29. https://doi.org/10.1007/s11515-007-0004-8
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    Bacillus cereus 58 (Bc58) is a UV-resistant wild type strain that has an ability to produce a sorrel pigment induced by L-tyrosine. The Fourier-transform infrared (FT-IR) spectra and chemical tests of its pigment are similar to that of the standard melanin (Sigma). A bioassay shows that the LC50 of a Bacillus thuringiensis (Bt) formulation added with the melanin of Bc58 and exposed to UV for 5 h is 16.1 µg/m1, which is similar to that of the Bt formulation without UV treatment, however, it is almost double that of the Bt formulation exposed to UV without the melanin of Bc58. The result of SDS-PAGE indicates that the melanin of Bc58 can protect the insecticidal crystal proteins from degradation. This suggests that it is an excellent UV protective agent for the insecticidal crystal proteins of the Bt formulation.
  • Genetic differentiation of Arthrobacter population from heavy metal-contaminated environment
    ZHANG Hanbo, REN Weimin, SHAO Qiyong, DUAN Changqun
    2007, 2(1): 30-34. https://doi.org/10.1007/s11515-007-0005-7
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    Six samples containing extremely high concentration of Pb, Zn, and Cd were obtained from the layers of 5-10 cm and 25-30 cm three tailing piles, with ages of about 10, 20 and more than 80 years, respectively. Then, 48 bacterial strains were obtained from these samples, and subsequently their phylogenetic positions were determined by analysis on the partial sequence of 16S rRNA gene (fragment length ranging from 474 to 708 bp). These isolates were members of the Arthrobacter genus, phylogenetically close to A. keyseri and A. ureafaciens, with sequence ranging from 99.1% to 100%. Furthermore, genetic variation between subpopulations from different samples was revealed by analysis on their randomly amplified polymorphic DNA profile. Nei genetic distance showed that the greatest differentiation occurred between subpopulation A and C. Notably, either genetic distance between subpopulations from the layers of 5-10 cm and 25-30 cm of each tailing pile or between same layers of different tailing pile increased with the history of tailings. Moreover, correlation analysis showed that soluble Pb has a significantly negative relationship with Nei  gene diversity of subpopulation. It was assumed that soluble Pb may be responsible for the reduced genetic diversity of the Arthrobacter population. Our data provided evidence that genetic differentiation of microbial populations was consistent with the changes of environmental factors, particularly heavy metals.
  • Effect of down-regulating VEGF on proliferation of colon carcinoma cell HT-29
    ZHANG Xiao, GE Yinlin, ZHANG Jinyu, ZHANG Zheng, WANG Xiuli, WANG Hongwei, CAO Mingzhi
    2007, 2(1): 35-38. https://doi.org/10.1007/s11515-007-0006-6
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    We designed specific small interfering RNA (siRNA) targeting vascular endothelial growth factor (VEGF) mRNA and synthesized oligo fragments, then siRNA was obtained by in vitro transcription and transfected into cultured human colon carcinoma cell line HT-29 with lipofectamine. We also analyzed the effect of the siRNA on proliferation of HT-29 cells by methyl thiazolyl tetrazolium (MTT) assay and expression level of VEGF mRNA of transfected cells by RT-PCR as well as amounts of secreted VEGF protein in the supernatant by enzyme linked immunosorbent assay (ELISA). Two groups of siRNA targeting human VEGF effectively inhibited proliferation of HT-29 cells after transfection. The secretion of VEGF protein also notably decreased, but the control scramble siRNA showed no effect.
  • Genetic structure and differentiation of Psathyrostachys huashanica populations detected with RAPD markers
    WANG Li, YANG Juan, GUO Jing, ZHAO Guifang
    2007, 2(1): 39-45. https://doi.org/10.1007/s11515-007-0007-5
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    Psathyrostachys huashanica Keng is a perennial grass and belongs to genus Psathyrostachys under Triticeae. sathyrostachys is found in the center of Middle Asia and the Caucasus Mountain, while P. huashanica, a species endemic to China, is only located in Mt. Hua in the Shaanxi province, China. At present, the population of this species is decreasing, and reaching the edge of extinction. Due to the limitation in distribution and the importance as breeding material for germplasm storage, it has been considered as first class among the national protected rare plants. For this reason, the present study is significant in probing plant flora, origin and evolution of Triticeae, and crop breeding. Randomly amplified polymorphic DNA (RAPD) markers were used to analyze the genetic structure and differentiation of P. huashanica populations sampled in three valleys (Huangpu, Xian, and Huashan Valleys) in Mt. Hua. One hundred and twenty-two RAPD fragments were obtained in all 266 individuals with 20 primers with a mean of 6.1 (2 10) fragments per primer. The percentage of polymorphic loci (PPB) was 60.66% in Huangpu Valley, 90.98% in Xian Valley, 95.08% in Huashan Valley, and the total PPB was 95.08%, which indicated a highly genetic variability of P. huashanica. The Shannon s Information index and GST were 0.3306 and 0.3263, respectively, indicating that there were more genetic variations within the subpopulations than those among the subpopulations. The gene flow among the subpopulations of P. huashanica (Nm = 1.0322) was much less than that of the common anemophytes (Nm = 5.24). Mean genetic distance is 0.1 571 (range: 0.0022 0.2901). The highest value of genetic distance was found between the subpopulation (hp1) of Huangpu Valley and the highest altitude subpopulation (h8) of Huashan Valley. Correlation analysis detected significant correlation between genetic distance and vertical distance of altitude. Clustering analysis and principal coordinate analysis revealed the genetic differentiation among the populations of P. huashanica. Differentiation mainly occurred between the higher altitude subpopulations and the lower altitude subpopulations, suggesting that altitude might be the major factor that restricted the gene flow between different altitude subpopulations and resulted in differentiation of subpopulations.
  • Genetic diversity in Isoetes yunguiensis, a rare and endangered endemic fern in China
    CHEN Jinming, LIU Xing, WANG Qingfeng, Wahiti R. Gituru
    2007, 2(1): 46-49. https://doi.org/10.1007/s11515-007-0008-4
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    Isoetes yunguiensis is an endangered and endemic fern in China. Field survey indicated that only one population and no more than 50 individuals occur in the wild. The genetic variation of 46 individuals from the population remaining at Pingba (Guizhou Province, China) was assessed by Random Amplified Polymorphic DNA (RAPD) fingerprinting. Twelve primers were screened from sixty ten-bp arbitrary primers, and a total of 95 DNA fragments were scored. Of these, 62.1% were polymorphic loci, which indicated that high level genetic variation existed in the natural population. The accumulation of genetic variation in the history of the taxon and the apparent minimal reduction effect on genetic diversity following destruction of habitat might be responsible for the high level genetic diversity presently remaining in the I. yunguiensis population. However, with the continuing decrease of population size, the genetic diversity will gradually be lost. We suggest that the materials from the extant population should be used for re-establishment of the populations.
  • Chemical compounds and pharmacological effects of Rabdosia excisa
    PANG Jinsong, LIU Bao, YU Qian
    2007, 2(1): 50-53. https://doi.org/10.1007/s11515-007-0009-3
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    Many kinds of diterpenoids have been isolated from Rabdosia spp. Some of them have anti-microbial effects, counteract inflammation, and inhibit tumor progression activities. We conducted the present study in order to look for bioactive compounds in the medicinal plant Rabdosia excisa. In this study, five compounds were isolated from R. excisa; they were oridonin, isokamebakaurin, oleanolic acid, ursolic acid, and β-sitosterol. In order to identify the function of the extracts, the activity of antibiotics, anti-oxidation, and immunity test were carried out against these functions. Prospective results were observed in all of the tested items.
  • Physiological response of riparian plants to watering in hyper-arid areas of Tarim River, China
    RUAN Xiao, WANG Qiang, CHEN Yaning, LI Weihong
    2007, 2(1): 54-61. https://doi.org/10.1007/s11515-007-0010-x
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    The physiological responses and adaptive strategies of Populus euphratica Oliv. (arbor species), Tamarix ramosissima Ldb. (bush species), and Apocynum venetum L. (herb species) to variations in water and salinity stress were studied in the hyper-arid environment of the Tarim River in China. The groundwater table, the saline content of the groundwater, as well as the content of free proline, soluble sugars, plant endogenous hormones (abscisic acid (ABA), and cytokinins (CTK)) of the leaves of the three species were monitored and analyzed at the lower reaches of the Tarim River in the study area where five transects were fixed at 100 m intervals along a vertical sampling line before and after water release. Saline stress dramatically increased soluble sugar concentration of the three species. Differences in sugar accumulation were determined among the species at different transects. The free proline concentration of the leaves of T. ramosissima and P. euphratica showed a proportional decrease with various degrees of elevation of the groundwater table after water release. There was a least correlation between the soluble sugars and proline stimulation in T. ramosissima. It was strongly suggested that T. ramosissima developed a different strategy to accumulate organic solutes to adapt to the stress environment. The soluble sugars and proline accumulation responded to the changes of groundwater table independently: the former occurred under salt stress, whereas the latter was more significant under drought stress. The concentration and the increase in concentration of ABA and CTK involved in stress resistance of the three species were also determined. This increase in the hormone concentration in P. euphratica was different from that of the other two species. Expressed as a function of increase of ABA concentration in leaves, A. venetum and T. ramosissima showed a different solute accumulation in response to groundwater table. There was a significant correlation between ABA accumulation andΔ [proline] in A. venetum as well as between ABA accumulation and Δ [sugar] in T. ramosissima.
  • Habitat fragmentation impacts on biodiversity of evergreen broadleaved forests in Jinyun Mountains, China
    YAN Ming, ZHONG Zhangcheng, LIU Jinchun
    2007, 2(1): 62-68. https://doi.org/10.1007/s11515-007-0011-9
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    The plant communities and their microclimates were surveyed and observed, and the soil fertilities were determined in six plots of evergreen broadleaved forests of different sizes and similar slope aspects on Jinyun Mountains of Chongqing in China from April to October, 2003. The relationships of biotic and abiotic factors were analyzed using the Simpson, Shannon Wiener, and Hill diversity indices, and stepwise multilinear regression analyses techniques. The results showed that compared with continuous evergreen broadleaved forests, five fragmentations had a lower species diversity index, and different life forms showed differences in diversity index. With the decrease in patch areas, the daily differences in air temperature (ΔTa), ground surface temperature (ΔTs), daily differences in relative humidity (ΔRH), maximum wind velocity (Vmax), differences in photosynthetic available radiation (ΔPAR) (at noon) of both edges and interiors, all tended to increase. Maximum wind velocity (Vmax) and photo effective radiation in forest edges were higher than those in interior forest, which presented a stronger temperature-gained edge effect. In all the fragmentations of evergreen broadleaved forests, the depth of the edge effect was the nearest from interior forest in the biggest patch (about 15 meters away from interior forest), while the depth of the edge effect was the farthest from interior forest in the smallest patch (about 25 meters away from interior forest). With regard to the water conservation function, soil water content improved along with increasing species diversity. Some of the nutritional function substances of soil increased with increasing species diversity. The elements of microclimate, such as Ta, ΔTa, ΔTs, ΔRH, Vmax, and PAR, changed along with the extent of fragmented forest.
  • Point pattern analysis of different age-classes of Larix principis-rupprechtii in Luya Mountain Reserve, Shanxi Province, China
    ZHANG Jintun, MENG Dongping
    2007, 2(1): 69-74. https://doi.org/10.1007/s11515-007-0012-8
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    Larix principis-rupprechtii forest is an important vegetation formation and has a large distribution area in Luya Mountain Reserve, China. Spatial pattern analysis on individual trees in different age-classes of Larix principis-rupprechtii was made in this paper. Here, we employed the technique of point pattern analysis, which could analyze patterns under all scales along a gradient. It was based on spatial mapped points of individual distribution. The results of this study showed that the densities of the five age-classes varied in the order: age-class 3>age-class 4>age-class 5>age-class 2>age-class 1. Although age-classes 1 and 2 have much fewer individuals than other three age-classes do, the population was stable at present. However, it would be necessary to take some measures for improving population regeneration for a long-time view. The individuals of all age-classes focused on clumping distribution in space; however, their distribution pattern varied with the change of scale. This mainly depended on biological features of Larix principis-rupprechtii and forest environments, but it also meant that the scale was an important factor in controlling spatial distribution pattern of tree individuals. The feature of clumping distribution became more significant with the increase of age. The relationships between individuals in different age-classes were almost all significantly correlated with each other. These associations became more significant within the older age-classes. This suggested that the individuals of different age-classes were interdistributed, by which the population could get benefits in resource utilization. The technique of point pattern analysis is effective and easy to be used in species pattern study. Its results are more closer to the reality, especially for community structure.
  • Effects of Arg26 and Lys27 mutation on the bioactivity of HNTX-IV
    XIONG Xia, XU Xia, LI Dongling, CHEN Ping, LIANG Songping
    2007, 2(1): 75-79. https://doi.org/10.1007/s11515-007-0013-7
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    Hainantoxin-IV (HNTX-IV) was isolated from the Chinese bird spider Ornithoctorcs hainana and identified as a novel antagonist of tetrodotoxin-sensitive (TTX-S) sodium channels. As revealed by the solution structure of HNTX-IV solved by two-dimensional nuclear magnetic resonance (2D-NMR), HNTX-IV adopts an inhibitor cystine knot motif. To check the role of basic residues during HNTX-IV s interaction with TTX-S sodium channels, R26A and K27A mutants of HNTX-IV were constructed by solid-phase chemical synthesis. The synthesized peptides were purified and refolded under optimized oxidation conditions. Correct synthesis and folding were confirmed by MALDI-TOF mass spectrometry and NMR spectroscopy, respectively. Using the whole-cell patch-clamp technique, Lys27 but not Arg26 was identified as a key residue for HNTX-IV s bioactivity against TTX-S sodium channels, because R26A-HNTX-IV showed slightly reduced activity and K27A-HNTX-IV showed almost no inhibition.
  • Experimental cloning of embryos through human-rabbit inter-species nuclear transfer
    JI Jingjuan, GUO Tonghang, TONG Xianhong, LUO Lihua, ZHOU Guixiang, FU Yingyun, LIU Yusheng
    2007, 2(1): 80-84. https://doi.org/10.1007/s11515-007-0014-6
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    Therapeutic cloning, which is based on human somatic cell nuclear transfer, is one of our major research objectives. Though inter-species nuclear transfer has been introduced to construct human somatic cell cloned embryos, the effects of type, passage, and preparation method of donor cells on embryo development remain unclear. In our experiment, cloned embryos were reconstructed with different passage and preparation methods of ossocartilaginous cell, skin fibroblast, and cumulus cells. The cumulus cell embryos showed significantly higher development rates than the other two (P<0.05). The development rate of embryos reconstructed with skin fibroblasts of different passage number and somatic cells of different chilling durations showed no significant difference. Also, fluorescence in situ hybridization (FISH) was conducted to detect nuclear derivation of the embryos. The result showed that the nuclei of the inter-species cloned embryo cells came from human. We conclude that (1) cloned embryos can be constructed through human-rabbit inter-species nuclear transfer; (2) different kinds of somatic cells result in different efficiency of nuclear transfer, while in vitro passage of the donor does not influence embryo development; (3) refrigeration is a convenient and efficient donor cell preparation method. Finally, it is feasible to detect DNA genotype through FISH.
  • Construction and immunogenicity of recombinant pseudorabies virus expressing the modified GP5m protein of porcine reproduction and respiratory syndrome virus
    JIANG Yunbo, FANG Liurong, XIAO Shaobo, ZHANG Hui, CHEN Huanchun
    2007, 2(1): 85-91. https://doi.org/10.1007/s11515-007-0015-5
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    Pseudorabies virus (PRV), an alpha-herpesvirus, has been developed as a live viral vector for animal vaccines. However, the PRV recombinant virus TK-/gE-/GP5+ expressing GP5 of porcine reproductive and respiratory syndrome virus (PRRSV), based on the PRV genetically depleted vaccine strain TK-/gE-/LacZ+, scarcely stimulated the vaccinated animals to produce neutralizing antibodies against PRRSV. To develop a booster-specific immune response of such PRV recombinants, the ORF5m gene (the modified ORF5 gene having better immune responses) was substituted for the ORF5 gene and introduced into PRV TK-/gE-/LacZ+, resulting in a PRV recombinant named TK-/gE-/GP5m+, which expressed the modified GP5m protein. The recombinant virus was confirmed using PCR, Southern blotting and Western blotting. TK-/gE-/GP5m+ and TK-/gE-/GP5+ expressing the authentic GP5 protein were inoculated into Balb/c mice to evaluate their immune responses. The results indicated that the protecting neutralization antibodies (the 3/6 vaccinated mice obtained 1:16) and cell immune responses induced by TK-/gE-/GP5m+ against PRRSV were higher than that induced by TK-/gE-/GP5+. Thus, the development of the new PRV recombinant expressing the modified GP5m protein as a candidate vaccine established the basis for the study of bivalent genetic engineering vaccines against PRRSV and PRV.
  • Fauna characteristics and ecological distribution of Carnivora and Artiodactyla in Niubeiliang National Nature Reserve, China
    ZENG Zhigao, SONG Yanling, MA Yingtai, WANG Xifeng, WU Xuntao, XIE Zhenfeng, SHAO Jianbin, LI Chunning
    2007, 2(1): 92-99. https://doi.org/10.1007/s11515-007-0016-4
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    Niubeiliang National Nature Reserve (NNR, 108?45µ 109?04µ E, 33?47µ 33?56µ N) is located on the eastern range of the Qinling Mountains in Shaanxi Province, China and spans the southern and northern slopes of Mt. Qinling. A transect survey and investigation were carried out in NNR to determine the fauna characteristics and ecological distribution of carnivora and artiodactyla from May 2003 to August 2004. The NNR has 18 mammals (carnivore and artiodactyl), two of which belong to the first class and seven to the second class of state key protected wildlife in China. The results of this study indicated that ungulates were abundant in the NNR, as all ungulates that were distributed within Mt. Qinling could be found within the reserve. However, only 45.5% of the carnivores distributed within Mt. Qinling were detected within the NNR. Among the mammals, there were 12 oriental species (66.7%), 1 palearctic specie (5.5%) and 5 widely-distributed species (27.8%). The NNR is a crossing area of palearctic species and oriental species on the zoogeographical regions, and it is a transitional area from the oriental realm to the palearctic realm. The results of the analysis on the ecological distribution of carnivore and artiodactyl in the area showed that their elevation ranges had large differences. The species whose elevation ranges above 1 300 m, about 1 000 m, and in 450 700 m occupied one third respectively. The results also indicated that species richness for the mammals in the NNR peaked at a middle elevation (rising at first, then descending with the increase in elevation). Not only on the southern slope, but also on the northern slope of Mt. Qinling, the number of species distributed in the area at 1 800 2 200 m a.s.l. was the largest (more than 80%), while the number of species distributed in the area above 2 600 m a.s.l. was the smallest (about 50%). Elevation gradients of species richness for the mammals in the NNR also embodied the mammal distributions among the vegetation types. The number of species distributed in the mixed coniferous and broadleaf deciduous forest at middle elevations was the largest, while the number of species distributed in the broadleaf deciduous forest at middle and low elevations, subalpine coniferous forest, subalpine shrubbery and meadow was relatively smaller.
  • Feeding habitats of blue sheep (Pseudois nayaur) during winter and spring in Helan Mountains, China
    LIU Zhensheng, WANG Xiaoming, CUI Duoying, LI Xinqing, LI Zhigang
    2007, 2(1): 100-107. https://doi.org/10.1007/s11515-007-0017-3
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    The feeding habitat selection of blue sheep (Pseudois nayaur) was studied by direct observation method in the Helan Mountains, China during winter (from November to December) and spring (from April to June) from 2003 to 2004. We established 25 line transects to collect information on feeding habitats used by blue sheep. Blue sheep in the study area preferred mountain savanna forests, a habitat dominated by Ulmus glaucescens, with medium tree density (<4 individuals / 400 m2), moderate tree height (4 6 m), higher shrub density (>5 individuals / 100 m2), higher shrub (>1.3 m), higher food abundance (>50 g), moderate distance to human disturbance (<500 m), and mild distance to bare rock (<2 m). Such habitats characterized by 12 ecological factors were preferred as feeding areas by blue sheep during winter. Similar to habitat selection by the species during winter, blue sheep also showed a preference for mountain savanna with tree dominated by Ulmus glaucescens and medium tree density (<4 individuals / 400 m2) during spring. Nevertheless, blue sheep preferred medium tree height (<6 m), moderate tree density (5 10 individuals / 100 m2), medium shrub height (1.3 1.7 m), higher food abundance (>100 g), moderate altitude (<2 000 m), moderate distance to water resource (<500 m), and medium hiding cover (50% 75%) during spring. Selection of the feeding habitats by sheep showed a significant difference in vegetation type, landform feature, dominant tree, tree height, shrub density, distance to the nearest shrub, food abundance, slope direction, slope degree, distance to water resource, and hiding cover between winter and spring. Results of principal components analysis indicated that the first principal component accounted for 24.493% of the total variance among feeding habitat variance during winter, with higher loadings for vegetation type, dominant tree, tree height, distance to the nearest tree, shrub density, shrub height, altitude, distance to water resource, and distance to human disturbance. In spring, the first principal components explained 28.777% of the variance, with higher loadings for vegetation type, distance to the nearest tree, shrub height, distance to the nearest shrub, food abundance, altitude, and distance to human disturbance.
  • Permeation mechanism of a two-state potassium channel
    WANG Xiangqun, ZHAO Tongjun, SONG Yang, ZHAN Yong
    2007, 2(1): 108-113. https://doi.org/10.1007/s11515-007-0018-2
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    A two-state hopping model was proposed to study the permeation of ion channel. The Nernst equation in equilibrium and the Michaelis-Menten relation in steady state were derived from the two-state kinetic model. The currentvoltage relationship obtained in the symmetrical solutions case was linear when the applied potential was less than 100 mV, which met Ohm s law. The conductance-concentration relationship exhibited the saturation property. Moreover, the characteristic time reaching the steady state of the KcsA channel was also discussed.