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81.
县域农业主导产业结构生态适宜性评价及其发展预测 总被引:2,自引:0,他引:2
基于生态适宜性“三基点”理论,采用动态赋权和拟合的方法,建立县域农业主导产业结构生态适宜性评价指标体系,并以山东省章丘市为例,对其县域农业主导产业结构生态适宜性进行评价.结果表明: 在有限的农业生态资源下,2005-2010年,章丘市4种农业主导产业的生态适宜性综合指数呈上升趋势;2011-2015年,则呈下降趋势,其中,2015年油料作物和水果的生态适宜性综合指数出现负值.对章丘市的应用研究证实了本文提出的县域农业主导产业结构生态适宜性评价方法的有效性及预测模型的合理性. 相似文献
82.
Yun CH Tang YH Feng YM An XM Chang WR Liang DC 《Biochemical and biophysical research communications》2005,326(1):52-59
Insulin and insulin-like growth factor 1 (IGF-1) share a homologous sequence, a similar three-dimensional structure and weakly overlapping biological activity, but IGF-1 folds into two thermodynamically stable disulfide isomers, while insulin folds into one unique stable tertiary structure. This is a very interesting phenomenon in which one amino acid sequence encodes two three-dimensional structures, and its molecular mechanism has remained unclear for a long time. In this study, the crystal structure of mini-IGF-1(2), a disulfide isomer of an artificial analog of IGF-1, was solved by the SAD/SIRAS method using our in-house X-ray source. Evidence was found in the structure showing that the intra-A-chain/domain disulfide bond of some molecules was broken; thus, it was proposed that disulfide isomerization begins with the breakdown of this disulfide bond. Furthermore, based on the structural comparison of IGF-1 and insulin, a new assumption was made that in insulin the several hydrogen bonds formed between the N-terminal region of the B-chain and the intra-A-chain disulfide region of the A-chain are the main reason for the stability of the intra-A-chain disulfide bond and for the prevention of disulfide isomerization, while Phe B1 and His B5 are very important for the formation of these hydrogen bonds. Moreover, the receptor binding property of IGF-1 was analyzed in detail based on the structural comparison of mini-IGF-1(2), native IGF-1, and small mini-IGF-1. 相似文献
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84.
用菠菜甜菜碱醛脱氢酶 ( BADH)免疫巴比西 ( BALB/c)小鼠 ,将其脾细胞与骨髓瘤细胞 SP2 /O-Ag1 4融合 ,在 1 92孔中 ,有约 1 4 %孔生长的杂交瘤细胞 ,用间接酶联免疫方法 ( ELISA)检测表现为阳性。选择其中 2 G3和 2 D10 细胞系 ,用有限稀释法进行克隆化培养 ,约 2 0 %克隆化细胞为强阳性。选择其中 2 G3- H3细胞株注射到 BALB/c小鼠腹腔中诱导腹水 ,腹水的单抗效价为 1∶ 1 0 3。应用 BADH单抗检查了大麦、水稻、高粱、小麦幼苗的叶片和根的粗提物 ,均呈阳性反应 ,表明 BADH除在光合组织中存在外 ,在非光合组织中也可能存在。讨论了非光合组织 BADH的意义 相似文献
85.
NMDA受体在海马CA3区习得性TP保持中的作用 总被引:1,自引:1,他引:1
The effect of microinjection of 2-amino-5-phosphonovaleric acid (APV), a selective NMDA receptor antagonist, into the rat hippocampal CA3 area on the synaptic efficacy and related conditioned behavior during the acquisition and consolidation of discrimination learning behavior was examined. The results showed: (1) After population spike (PS) amplitude had just increased to the maximum through training i.e. learning-dependent LTP had just formed, APV 1 microliter (2 mmol/L) was injected into CA3 area, then the rats were trained during the time of efficacy of the drug in every experimental block. The result demonstrated that the PS amplitude could not be maintained at the highest level but decreased to the pre-experiment level after 8 blocks. Correct response percentage of rats could not be consolidated with further training but decreased to less than 10%. (2) After the PS amplitude had kept up at the highest level, APV 1 microliter (2 mmol/L) was injected into CA3 area, then the rats were trained during the time of efficacy of the drug in every experimental block, in which case the PS amplitude also could not be maintained at the highest level but decreased to the pre-experiment level after 14 blocks. Correlatively, when the correct response percentage of rats decreased gradually to less than 10%, the conditioned response of the animals extinguished, but its extinction speed was slower than it was in result (1). These results suggest that the NMDA receptor in CA3 area plays an important role in the maintenance of the learning-dependent long-term potentiation. 相似文献
86.
神经干细胞的分化调控一直是发育神经生物学的重要研究课题。综述了调节胚胎和成体神经干细胞分化的细胞内在因素和外部环境因素,初步探讨了胚胎和成体神经干细胞分化机制的差异。 相似文献
87.
88.
本文在建立了基因工程FR-008/杀念菌素脱羧衍生物CS103分离提取工艺的基础上, 经进一步纯化, 获得一定供试样品。通过对比脱羧FR-008/杀念菌素CS103、FR-008/杀念菌素和两性霉素B三种化合物对人胚肾细胞毒性、对人血红细胞的溶血活性和对白色念珠菌的抗菌效果, 发现脱羧FR-008/杀念菌素CS103的毒性较FR-008/杀念菌素和两性霉素B大大降低, 且保持了较高的抗真菌(Candida albicans)活性。 相似文献
89.
酵母甘露聚糖(Mannan,简称Man)是能参与生物信息流影响生物体、特别是在糖基化方面起着重要调控作用的生物信息大分子.它是否能在抑制生物机体中肿瘤生长方面具有重要作用?研究结果表明:酵母甘露聚糖既能使患S-180瘤鼠的体质增强的同时又有抑制其体内所患S-180瘤生长的功效.Man抑制患鼠机体内的S-180瘤生长的功效(抑瘤率)随用量的增加而提高,当Man用量达360 mg(40 mg/Kg/d·9d)时,其抑瘤率达98.4%的最高水平,此时鼠体重增加1.66倍.Man的抑瘤功效有最佳适用量并存在性别敏感性,通常是雄性鼠的抑瘤率高于雌性鼠.Man抑制鼠S-180肿瘤生长的作用优于市售5-氟尿嘧啶的作用. 相似文献
90.