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931.
932.
933.
胡杨、灰叶胡杨果实空间分布及其数量特性的研究 总被引:5,自引:0,他引:5
胡杨、灰叶胡杨种间比较,果穗、种子在树冠上的垂直分布均表现为树冠上层最多,中层居中,下层最少,树冠南北侧相比较,南侧果穗量多于北侧.单果种子量在树冠各层次上差异不显著.胡杨单果重是灰叶胡杨的2.68倍,千粒重是灰叶胡杨的1.33倍,单果种子量是灰叶胡杨的2.14倍,单株种子量是灰叶胡杨的1.28倍,而单株果实量灰叶胡杨是胡杨的1.59倍.同一个种不同居群间比较,胡杨、灰叶胡杨均是单株果穗数和果穗果实数各居群间都存在差异,胡杨各居群间单果重、单果种子量差异不显著,而灰叶胡杨各居群间单果重及单果种子量差异极显著.表明胡杨在物质和能量上对后代的投资能力强于灰叶胡杨,生殖策略是通过较高的单果种子量来保证一定数量的单株种子量;而灰叶胡杨单果种子量较低,却是通过较高的单株果量来保证单株种子量,并且较小的种子占据空间生态位的潜能较胡杨占优势. 相似文献
934.
LT(K63/R72), a New Mutant of Escherichia coli Heat-labile Enterotoxin, Exhibits Characteristics More Similar to LT(K63) than LT(R72) 总被引:3,自引:0,他引:3
LT(K63), a non-toxic mutant and LT(R72), a low toxic mutant of E. coli heat-labile enterotoxin are frequently used mucosal adjuvants. In many cases, the adjuvanticity of LT(K63) is lower than that of LT(R72), but LT(K63), which induces a mixed Th1/Th2 response, exhibits a higher level of protection than LT(R72) which induces a polarized Th2-type response. To utilize the advantages of both adjuvants, a doublemutation LT(K63/R72) was generated and purified. The characterization results showed that there was no significant difference in production rate and immunogenicity between wild type LT and LT mutants. The results also showed that the toxicity and the trypsin sensitivity of LT(K63/R72) are between that of LT(K63)and LT(R72). Using HPLC, when samples in an OHpak SB-800 column were eluted by denatural buffer(TEAN containing 10 mg/ml SDS), we found the stability of LT(K63/R72) was higher than that of LT(R72)and lower than that of LT(K63). Through further analyzes, we found that LT(K63/R72) exhibits characteristics more closely related to LT(K63) than LT(R72). 相似文献
935.
Gao JP Yong ZH Zhang F Ruan KC Xu CH Chen GY 《Acta biochimica et biophysica Sinica》2005,37(11):737-742
To determine the contribution of charged amino acids to binding with the photosystem II complex (PSII), the amino or carboxyl groups of the extrinsic 18 kDa protein were modified with N- succinimidyl propionate (NSP) or glycine methyl ester (GME) in the presence of a water-soluble carbodiimide, respectively. Based on isoelectric point shift, 4-10 and 10-14 amino groups were modified in the presence of 2 and 4 mM NSP, respectively. Similarly, 3-4 carboxyl groups were modified by reaction with 100 mM GME. Neutralization of negatively charged carboxyl groups with GME did not alter the binding activity of the extrinsic 18 kDa protein. However, the NSP-modified 18 kDa protein, in which the positively charged amino groups had been modified to uncharged methyl esters, failed to bind with the PSII membrane in the presence of the extrinsic 23 kDa protein. This defect can not be attributed to structural or conformational alterations imposed by chemical modification, as the fluorescence and circular dichroism spectra among native, GME- and NSP-modified extrinsic 18 kDa proteins were similar. Thus, we have concluded that the positive charges of lysyl residues in the extrinsic 18 kDa protein are important for its interaction with PSII membranes in the presence of the extrinsic 23 kDa protein. Furthermore, it was found that the negative charges of carboxyl groups of this protein did not participate in binding with the extrinsic 23 kDa protein associated with PSII membranes. 相似文献
936.
Yuanzhen Xu Hongbo Wei Jianjun Chen Kun Gao 《Bioorganic & medicinal chemistry letters》2019,29(2):281-283
Three new 2,4-dinitrobenzenesulfonyl derivatives 1–3 were successfully prepared for the first time using a simple process. They were efficiently triggered by thiols (glutathione and l-cysteine) to release the corresponding phenol derivatives (4–6) within 5?min. The quick response of 1–3 toward thiols was determined by 1H NMR and HPLC. Moreover, our results indicated that 1 could induce DNA cross-linking in the presence of glutathione, probably due to the quinone methide formation of phenol intermediate 4 followed by departure of 2,4-dinitrobenzenesulfonyl group. 相似文献
937.
Hongyan Liu Xiaoming Qiang Qing Song Wei Li Yuxi He Chanyuan Ye Zhenghuai Tan Yong Deng 《Bioorganic & medicinal chemistry》2019,27(6):991-1001
A series of 4′-OH flurbiprofen Mannich base derivatives were designed, synthesized and evaluated as potential multifunctional agents for the treatment of Alzheimer’s disease. The biological screening results indicated that most of these derivatives exhibited good multifunctional activities. Among them, compound 8n demonstrated the best inhibitory effects on self-induced Aβ1-42 aggregation (65.03% at 25.0?μM). Moreover, this representative compound also exhibited good antioxidant activity, biometal chelating ability and anti-neuroinflammatory activity in vitro. Furthermore, compound 8n displayed appropriate blood-brain barrier permeability. These multifunctional properties highlight compound 8n as promising candidate for further development of multi-functional drugs against AD. 相似文献
938.
Shan-He Yu Kang-Yong Zhu Fan Zhang Juan Wang Hao Yuan Yi Chen Yi Jin Mei Dong Lei Wang Xiao-E Jia Lei Gao Zhi-Wei Dong Chun-Guang Ren Li-Ting Chen Qiu-Hua Huang Min Deng Leonard I. Zon Yi Zhou Ting-Xi Liu 《Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms》2018,1861(2):106-116
The histone demethylase Jmjd3 plays a critical role in cell lineage specification and differentiation at various stages of development. However, its function during normal myeloid development remains poorly understood. Here, we carried out a systematic in vivo screen of epigenetic factors for their function in hematopoiesis and identified Jmjd3 as a new epigenetic factor that regulates myelopoiesis in zebrafish. We demonstrated that jmjd3 was essential for zebrafish primitive and definitive myelopoiesis, knockdown of jmjd3 suppressed the myeloid commitment and enhanced the erythroid commitment. Only overexpression of spi1 but not the other myeloid regulators rescued the myeloid development in jmjd3 morphants. Furthermore, preliminary mechanistic studies demonstrated that Jmjd3 could directly bind to the spi1 regulatory region to alleviate the repressive H3K27me3 modification and activate spi1 expression. Thus, our studies highlight that Jmjd3 is indispensable for early zebrafish myeloid development by promoting spi1 expression. 相似文献
939.
940.
Linkage and association mapping reveals the genetic basis of brown fibre (Gossypium hirsutum) 总被引:1,自引:0,他引:1
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Tianwang Wen Mi Wu Chao Shen Bin Gao De Zhu Xianlong Zhang Chunyuan You Zhongxu Lin 《Plant biotechnology journal》2018,16(9):1654-1666
Brown fibre cotton is an environmental‐friendly resource that plays a key role in the textile industry. However, the fibre quality and yield of natural brown cotton are poor, and fundamental research on brown cotton is relatively scarce. To understand the genetic basis of brown fibre cotton, we constructed linkage and association populations to systematically examine brown fibre accessions. We fine‐mapped the brown fibre region, Lc1, and dissected it into 2 loci, qBF‐A07‐1 and qBF‐A07‐2. The qBF‐A07‐1 locus mediates the initiation of brown fibre production, whereas the shade of the brown fibre is affected by the interaction between qBF‐A07‐1 and qBF‐A07‐2. Gh_A07G2341 and Gh_A07G0100 were identified as candidate genes for qBF‐A07‐1 and qBF‐A07‐2, respectively. Haploid analysis of the signals significantly associated with these two loci showed that most tetraploid modern brown cotton accessions exhibit the introgression signature of Gossypium barbadense. We identified 10 quantitative trait loci (QTLs) for fibre yield and 19 QTLs for fibre quality through a genome‐wide association study (GWAS) and found that qBF‐A07‐2 negatively affects fibre yield and quality through an epistatic interaction with qBF‐A07‐1. This study sheds light on the genetics of fibre colour and lint‐related traits in brown fibre cotton, which will guide the elite cultivars breeding of brown fibre cotton. 相似文献