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BackgroundC4ST-1 catalyzes the transfer of sulfate groups in the sulfonation of chondroitin during chondroitin sulfate synthesis. Chondroitin sulfate consists of numerous copies of negatively charged sulfonic acid groups that participate in the nucleation process of biomineralization. In the present study, we obtained two CHST11 genes (PmCHST11a and PmCHST11b) which encoded the C4ST-1 and explored the functions of these genes in the synthesis of chondroitin sulfate and in the formation of the nacreous layer of shells.ResultsBoth PmCHST11a and PmCHST11b had a sulfotransferase-2 domain, a signal peptide and a transmembrane domain. These properties indicated that these genes localize in the Golgi apparatus. Real-time PCR revealed that both PmCHST11a and PmCHST11b were highly expressed in the central zone of the mantle tissue. Inhibiting PmCHST11a and PmCHST11b via RNA interference significantly decreased the expression levels of these genes in the central zone of the mantle tissue and the concentration of chondroitin sulfate in extrapallial fluid. Moreover, shell nacre crystallized irregularly with a rough surface after RNA interference.ConclusionsThis study indicated that PmCHST11a and PmCHST11b are involved in the nacre formation of Pinctada fucata martensii through participating in the synthesis of chondroitin sulfate. 相似文献
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Montgomery multiplication over rings 总被引：1，自引：0，他引：1
Montgomery multiplication of two elements a and b of a finite field Fq is defined as abr-1 where r is a fixed field element in . In this paper we define Montgomery multiplication of elements a(x) and b(x) in a polynomial ring modulo the ideal generated by a reducible polynomial f(x). We then show that Montgomery multiplication over a field represented by a polynomial ring modulo an irreducible pentanomial can be performed more efficiently in terms of time delay by embedding the field in a quotient of a polynomial ring modulo a reducible trinomial. The trinomial has a degree that is slightly higher than that of the pentanomial, thereby increasing the number of gates in the multiplier by a small amount. 相似文献
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“大豆优异基因资源发掘及其基因组研究” 立项背景和意义 总被引：3，自引：0，他引：3
大豆是重要的粮食和油料作物,在我国国民经济发展中具有重要地位
。在中国加入WTO的形势下,我国大豆面临着生产落后、供给严重不足、国内大豆产业受到
进口转基因大豆的严重冲击的局面。我国是大豆的起源中心,收集保存的大豆资源蕴藏着丰\\r
富的有益基因。开展大豆优异基因资源发掘、大豆基因组序列测定与生物信息学分析、大豆
优异基因的分子标记、定位与克隆等关键科学问题研究,将推动大豆的分子生物学研究并提\\r
高大豆的分子育种水平,为大豆遗传改良奠定坚实的理论基础。针对这些内容,2003年国家
自然科学基金委员会设立了重大项目“大豆优异基因资源发掘及其基因组研究”。 相似文献
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J.E. Rubio 《Journal of The Franklin Institute》1980,309(5):301-308
Control problems in Hilbert spaces are treated in a measure-theoretical framework; instead of dealing with a set of admissible trajectory-control pairs, a set of measures defined by the boundary conditions and the differential equations of the problem are considered. The concept of weak controllability is introduced; a system has this property if every pair of initial and final points, (ta,xa) and (tb,xb) can be weakly joined; this is possible if a set of linear equalities involving measures has a solution. In turn, this is shown to be equivalent to the possibility of extending a linear functional in a positive manner. Necessary and sufficient conditions for controllability are derived, and applied to the study of a finite-dimensional system with the control appearing linearly. 相似文献
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Sastry S. Burra Hemalatha Reddy P. Suryanarayana Murthy 《Indian journal of clinical biochemistry : IJCB》1995,10(2):126-128
The effect of the antitubercular drugs isoniazid (10 μg/ml), ethambutol (10 μg/ml), rifampicin (0.5 μg/ml) and streptomycin
(1 μg/ml) on the calmodulin like protein (CAMLP) content ofMycobacterium tuberculosis H37Rv andM. tuberculosis H37Ra was investigated. The drugs were added to actively growing cells at their mid log phase of growth (14 days) and after 12
more hours of incubation, CAMLP was estimated. In both the mycobacteria, all the four antitubercular drugs CAMLP. 相似文献
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Alfred Landé 《Journal of The Franklin Institute》1940,229(6):767-774
In order to quantize Dirac's classical point electron1 we supplement Einstein's classical equation (E/c)2 ? p2 = b2 with a reciprocal classical equation (CΔt)2 ? (Δr)2 = a2 where b = mc and a is Dirac's signal radius. Δt is the time saved by a light signal in various states of motion of the electron, and a/c is the rest time saved. Our former efforts2 of obtaining an integral equation for the probability amplitude have been rectified by Born.3 There is no solution of the integral equation, however, unless advanced and retarded phases are introduced simultaneously, along with Dirac's advanced and retarded potentials. We have obtained a transcendental equation for the eigen-value μ = αγ where α is the Sommerfeld fine-structure constant, and γ is the numerical factor in Dirac's signal radius a = γe2/mc2. The smallest eigen-value is μ = 0.0299.That is, ab = hγ = h/210. 相似文献
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"分子模块设计育种创新体系"战略性先导科技专项以水稻为主,小麦、鲤等为辅,利用野生种、农家品种和主栽(养)优良品种等种质资源,综合运用基因组学、系统生物学、合成生物学等手段,解析高产、稳产、优质、高效等重要农艺(经济)性状的分子模块,揭示水稻复杂性状全基因组编码规律,发展多模块非线性耦合理论和"全基因组导航"分子模块设计育种技术,优化多模块组装的品种设计的最佳策略,建立从"分子模块"到"设计型品种"的现代生物技术育种创新体系,为实现全基因组水平多模块优化组装、培育新一代超级品种提供系统解决方案。文章介绍了该专项的背景、总体目标、研究内容、进展及发展展望。 相似文献
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Johnny R. Johnson David E. Johnson Ronald J. Lacarna 《Journal of The Franklin Institute》1979,307(3):175-182
Transitional XY filters (TXY) are considered with characteristics that vary smoothly from those of filter X to those of filter Y as a parameter is varied continuously. Emphasis is placed on transitional ultraspherical—Thomson (TUT) filters and transitional ultraspherical “a”-ultraspherical “b” (TABU) filters. 相似文献
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BackgroundWe aimed to test the possibility of improving polypeptide production from soybean meal fermentation by engineered Aspergillus oryzae strains. Four different protease genes were cloned and transformed into wild-type A. oryzae, and the engineered A. oryzae strains were then used for soybean meal fermentation.ResultsThe results showed different degrees of improvement in the protease activity of the four transformants when compared with wild-type A. oryzae. A major improvement in the polypeptide yield was achieved when these strains were used in soybean meal fermentation. The polypeptide conversion rate of one of the four transformants, A. oryzae pep, reached 35.9%, which was approximately twofold higher than that exhibited by wild-type A. oryzae. Amino acid content analysis showed that the essential amino acid content and amino acid composition of the fermentation product significantly improved when engineered A. oryzae strains were used for soybean meal fermentation.ConclusionsThese findings suggest that cloning of microbial protease genes with good physicochemical properties and expressing them in an ideal host such as A. oryzae is a novel strategy to enhance the value of soybean meal. 相似文献
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BackgroundWheat is one of the most important crops cultivated all over the world. New high-yielding cultivars that are more resistant to fungal diseases have been permanently developed. The present study aimed at the possibility of accelerating the process of breeding new cultivars, resistant to eyespot, by using doubled haploids (DH) system supported by marker-assisted selection.ResultsTwo highly resistant breeding lines (KBP 0916 and KBH 4942/05) carrying Pch1 gene were crossed with the elite wheat genotypes. Hybrid plants of early generations were analyzed using endopeptidase EpD1 and two SSR markers linked to the Pch1 locus. Selected homozygous and heterozygous genotypes for the Pch1-linked EpD1b allele were used to produce haploid plants. Molecular analyses were performed on haploids to identify plants possessing Pch1 gene. Chromosome doubling was performed only on haploid plants with Pch1 gene. Finally, 65 DH lines carrying eyespot resistance gene Pch1 and 30 lines without this gene were chosen for the eyespot resistance phenotyping in a field experiment.ConclusionsResults of the experiment confirmed higher resistance to eyespot of the genotypes with Pch1 in comparison to those without this gene. This indicates the efficiency of selection at the haploid level.How to cite: Wiśniewska H, Majka M, Kwiatek M, et al. Production of wheat doubled haploids resistant to eyespot supported by marker-assisted selection. Electron J Biotechnol 2019;37. https://doi.org/10.1016/j.ejbt.2018.10.003 相似文献
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Mayo Dyer Hersey 《Journal of The Franklin Institute》1935,220(2):187-191
In Part I properties of the scale coördinate, of the form: B(n + θ) are discussed. n is shown to be associated with the operation of counting scale marks, θ with the operation of estimating between them, and B, with the operational and configurational aspects of that part of apparatus which lies adjunct to the scale system.In Part II three types of measurement codification are discussed: (a) the differential interval; (b) the finite amorphous interval; (c) the scale interval; a relationship among them is postulated.In Part III the finite differences in scale coördinates are defined and simple theorems are used to illustrate these definitions. Simple difference equations in scale coördinates are solved to illustrate macroscopic “selection principles” arising partly out of the methodology of codifying a coincidence in scale coördinates.In Part IV an example of causally related dimensional systems is described by use of the scale coördinate. This example is taken from the perfect gas law and Van der Waals' gas law. 相似文献
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BackgroundMutation breeding is one of the most important routes to achieving high docosahexaenoic acid (DHA) productivity using Schizochytrium. However, few selection strategies have been reported that aim to generate a high DHA content in Schizochytrium lipids.ResultsFirst, culture temperature altered the butanol tolerance of Schizochytrium limacinum B4D1. Second, S. limacinum E8 was obtained by selecting mutants with high butanol tolerance. This mutant exhibited a 17.97% lower proportion of DHA than the parent strain S. limacinum B4D1. Third, a negative selection strategy was designed in which S. limacinum F6, a mutant with poor butanol tolerance, was obtained. The proportion of DHA in S. limacinum F6 was 11.22% higher than that of parent strain S. limacinum B4D1. Finally, the performances of S. limacinum B4D1, E8 and F6 were compared. These three strains had different fatty acid profiles, but there was no statistical difference in their biomasses and lipid yields.ConclusionIt was feasible to identified the relative DHA content of S. limacinum mutants based on their butanol tolerance. 相似文献
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J.L. Finck 《Journal of The Franklin Institute》1940,229(2):201-221
This paper is a continuation of a previous paper published in this JOURNAL. The basic idea in the two papers is to enlarge the assemblage of thermodynamic states by including the so-called “metastable” states. Considering a system, in one or two phases, which has a single type of transformation, the writer develops an equation of state of the form η = a + by + cp + dpv + (e + fv + gp + hpv) In T, where p, v, T are three independent variables, and a, b, c, etc. are constants.The latent heat at p, T = constant is λP,T = I (v2 -v1) [b+db+(f+hp) InT), which is derived from the equation of state.The available thermodynamic data on ammonia and steam are used to check these equations. It is found that within the saturated region the agreement is quite satis factory, whereas for the superheated region the agreement is not so good. 相似文献
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大豆是一种重要的农产品资源,压榨行业是大豆产业链上的重要环节,它的原料来自大豆种植业,生产的豆粕主要用作饲料业和畜牧业的蛋白原料。自1996年以来,中国大豆进口量不断增加,是全球最大的大豆压榨国,大豆压榨企业布局发生了重大变化。美国和巴西是世界上最大的大豆生产国,也是主要的大豆压榨国,对比分析美国、巴西及中国大豆压榨企业布局特征,对指导中国未来大豆压榨企业投资布局具有重要意义。本文根据项目组20多年持续收集的相关资料,以及美国农业部、巴西植物油加工协会的资料,对比美国、巴西和中国的大豆供求基本特点、大豆生产布局、畜牧业和饲料业分布、大豆压榨企业和产能布局特点发现,美国、巴西的大豆压榨企业主要集中在大豆主产区,并与其国内豆粕市场空间高度重合,呈现“大集聚、小分散”的布局形态;而中国大豆压榨企业布局和大豆制品销区在空间上不完全重合,逐渐形成了以沿海港口城市为压榨核心,以长江、哈大铁路等交通运输线路扩散的带状布局形态。区域畜牧业、饲料业发展决定着豆粕市场需求空间,但是大豆原料供给与豆粕需求在空间上往往存在差异,除了不同国家和区域的产业政策外,大豆原料及豆粕的运费成本、豆粕的市场潜力、区域内大豆压榨产能规模及企业间分工协作所产生的集聚效应是造成大豆压榨企业空间布局形态存在巨大差异的主要原因。 相似文献
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BackgroundIn industrial yeasts, selection and breeding for resistance to multiple stresses is a focus of current research. The objective of this study was to investigate the tolerance to multiple stresses of Saccharomyces cerevisiae obtained through an adaptive laboratory evolution strategy involving a repeated liquid nitrogen freeze–thaw process coupled with multi-stress shock selection. We also assessed the related resistance mechanisms and very high-gravity (VHG) bioethanol production of this strain.ResultsElite S. cerevisiae strain YF10-5, exhibiting improved VHG fermentation capacity and stress resistance to osmotic pressure and ethanol, was isolated following ten consecutive rounds of liquid nitrogen freeze–thaw treatment followed by plate screening under osmotic and ethanol stress. The ethanol yield of YF10-5 was 16% higher than that of the parent strain during 35% (w/v) glucose fermentation. Furthermore, there was upregulation of three genes (HSP26, HSP30, and HSP104) encoding heat-shock proteins involved in the stress response, one gene (TPS1) involved in the synthesis of trehalose, and three genes (ADH1, HXK1, and PFK1) involved in ethanol metabolism and intracellular trehalose accumulation in YF10-5 yeast cells, indicating increased stress tolerance and fermentative capacity. YF10-5 also showed excellent fermentation performance during the simultaneous saccharification and fermentation of VHG sweet potato mash, producing 13.40% (w/v) ethanol, which corresponded to 93.95% of the theoretical ethanol yield.ConclusionsA multiple-stress-tolerant yeast clone was obtained using adaptive evolution by a freeze–thaw method coupled with stress shock selection. The selected robust yeast strain exhibits potential for bioethanol production through VHG fermentation.How to cite: Zhang Q, Jin Y, Fang Y, et al. Adaptive evolution and selection of stress-resistant Saccharomyces cerevisiae for very high gravity bioethanol fermentation. Electron J Biotechnol 2019;41. https://doi.org/10.1016/j.ejbt.2019.06.003 相似文献
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BackgroundAssessments of genetic diversity are essential for germplasm characterization and exploitation. Molecular markers are valuable tools for exploring genetic variation and identifying germplasm. They play key roles in a Xanthoceras sorbifolia breeding program.ResultsWe analyzed the genetic diversity of populations of this species using 23 simple sequence repeat (SSR) loci and data on kernel oil content. The 11 populations included in the study were distributed across a large geographic range in China. The kernel oil content differed significantly among populations. The SSR marker analysis detected high genetic diversity among the populations. All SSRs were polymorphic, and we identified 80 alleles across the populations. The number of alleles at each locus ranged from two to six, averaging 3.48 per primer pair. The polymorphism information content values ranged from 0.35 to 0.70, averaging 0.51. Expected heterozygosity, observed heterozygosity, and Shannon's information index calculations detected large genetic variations among populations of different provenance. The high average number of alleles per locus and the allelic diversity observed in the set of genotypes analyzed indicated that the genetic base of this species was relatively wide. The statistically significant positive correlation between genetic and geographic distances suggested adaptations to local conditions.ConclusionsMicrosatellite markers can be used to efficiently distinguish X. sorbifolia populations and assess their genetic diversity. The information we have provided will contribute to the conservation and management of this important plant genetic resource. 相似文献
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Ross Gunn 《Journal of The Franklin Institute》1943,236(4):373-390
The deformation of a strong elastic lithosphere supported by an underlying weak magma is calculated for a long mountainous load. The deformations, produce vertical superposed stresses in the lithosphere that contribute to the support of the mountain and distribute its weight over a large area.Employing the principle of isobaric equilibrium, the distribution of the vertical supporting stress and the associated gravity anomalies may be determined by analysis.The results of the analysis are applied to the Hawaiian chain and it is shown that the calculated physical properties and gravity anomalies are remarkably like those observed. It is inferred from the study that: (a) a strong lithosphere underlies the Hawaiians and this section is practically identical with those underlying other regions; (b) the lithosphere will support one-sided stresses approximating 109 dynes/cm.2 for long periods of time; (c) the distribution of gravity anomaly may be described quantitatively in terms of the calculated deformations; (d) the principle of isobaric equilibrium is obeyed throughout the region whereas the isostatic principle is generally violated; and (e) the distribution of compensating masses is not at all like that demanded by the principle of isostasy.It is concluded that isostasy leads to results that are clearly wrong when applied to mountains or other deformed regions. The principle of isobaric equilibrium appears, however, to be well established by the investigation. 相似文献