排序方式： 共有8条查询结果，搜索用时 15 毫秒
1
1.
针对山东蒙山发育的第四纪冰川遗迹,采用光释光的测年方法,获得了8.2ka冰期年龄值,以此为基础建立了拦马冰期,属于全新世早期。为了能够获得其他测年成果的相互验证,该次研究采用了宇生核素的测年方法,获得了3个年龄值:7.01ka,8.57ka,9.95ka,均属于全新世早期,与光释光方法获得的年龄值具有较高的一致性。在海拔752m的清荣峡谷内的冰碛表面,获得了5.27ka的全新世中期的年龄,对应冰碛建立了清荣冰期。通过该项研究,结合蒙山冰川遗迹的特征及其风化程度,反映了冰川遗迹、测年数据与环境气候之间的吻合性,综合确认了我国东部全新世早期拦马冰期、全新世中期清荣冰期的存在,也证明了全新世,在山东蒙山及我国东部中低山区受到东亚冷槽的影响,曾经存在冰川作用。 相似文献
2.
通过羟自由基清除作用、超氧自由基清除作用、还原能力和金属螯合能力等抗氧化活性实验，测定了白色霞水母蛋白的抗氧化活性。实验结果表明：白色霞水母蛋白具有较高的清除羟自由基的能力，蛋白质量浓度为41μg／mL时，清除率可达到85％；白色霞水母蛋白对超氧阴离子的清除作用较弱，蛋白质量浓度为77．7μg／mL时，清除率〈50％；白色霞水母蛋白有较强的还原能力，但没有螯合能力；白色霞水母蛋白的抗氧化活性受温度影响不大，且巯基含量不是影响抗氧化活性的主要因素。 相似文献
3.
Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O-2)/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfa... 相似文献
4.
In this study, several methods were compared for the efficiency to concentrate venom from the tentacles of jellyfish Rhopilema esculentum Kishinouye. The results show that the methods using either freezing-dry or gel absorption to remove water to concentrate venom are not applicable due to the low concentration of the compounds dissolved. Although the recovery efficiency and the total venom obtained using the dialysis dehydration method are high, some proteins can be lost during the concentrating process. Comparing to the lyophilization method, ultrafiltration is a simple way to concentrate the compounds at high percentage but the hemolytic activities of the proteins obtained by ultrafiltration appear to be lower. Our results suggest that overall lyophilization is the best and recommended method to concentrate venom from the tentacles of jellyfish. It shows not only the high recovery efficiency for the venoms but high hemolytic activities as well. 相似文献
5.
7.
The present work is the first report of the biochemical characterization of the venom from nematocysts of the jellyfish Rhopilema esculentum Kishinouye. The nematocysts were isolated by autolysis and centrifugation and separated by flow cytometry. Four types of
nematocysts were identified: mastigophores, euryteles, and atrichous and holotrichous isorhiza. SDS-PAGE and amino acid analyses
demonstrated that most of the proteins in the nematocyst extract were between 10 kDa and 40 kDa, and that glutamic acid was
the main amino acid. A hemolytic activity assay showed that the activity of the nematocyst venom (RNV) was strongest in Tris-HCl
buffer (50 mmol/L, pH 7.8, 5% glycerol, 0.5 mmol/L EDTA, 0.1 mol/L NaCl). The hemolytic activity was related to protein concentration
and the HU50 against chicken erythrocytes was 0.91 μg/mL. 相似文献
8.
从霞水母Cyanea sp.中分离刺丝囊,提取刺丝囊毒素(NV),并研究了温度、pH和几种化学组分对其溶血活性稳定性的影响.实验结果表明,在4～37℃范围内NV的溶血活性与温度变化密切相关,毒素在4℃以下几乎没有发生溶血反应,在37℃以下反应45 min以后,溶血活性达到最大值;毒素的溶血活性对pH敏感,在pH 7.8时.溶血活性最强,溶血率为93.53%.EDTA、NaCl和还原型谷胱甘肽(GSH)对NV溶血活性都具有稳定作用.通过正交实验发现,GSH对溶血活性的影响最大,当提取液中含有1.0 mmol/L GSH和5.0 mmol/L NaCl时毒素的溶血活性最强.DTT(二硫苏糖醇)明显降低毒素的溶血活性,说明毒素中溶血蛋白的活性很可能与分布在蛋白质表面的二硫键有关.Ca2+虽然能够增强毒素的溶血活性但是对毒素并没有稳定作用,所以Ca2+可能只是毒素溶血活性的活化剂.甘油对毒素的稳定作用不明显. 相似文献
1