排序方式: 共有25条查询结果,搜索用时 15 毫秒
1.
利用3'-RACE-PCR方法首次从药用真菌猪苓中克隆得到与真菌形态发育相关的溶血素基因。结果表明,猪苓溶血素基因的全长cDNA为744bp,其中编码区占447bp,共编码148个氨基酸,推测其分子量约为15.79kDa,理论等电点为4.89。推定的猪苓溶血素蛋白具有与杨树菇溶血素类蛋白家族相同的结构域和功能位点,两者同源性为60%。系统进化树结果显示猪苓溶血素隶属于担子菌类群。实时荧光定量PCR分析结果表明在菌核形成初期猪苓溶血素基因表达量较高,且显著高于菌丝体中猪苓溶血素基因的转录水平,说明溶血素基因参与了猪苓菌核的形态发育。 相似文献
2.
Chisa Okada Akio Nakamura Shigeo Tomioka Kazuhiro Kohama Takako S. Kaneko 《Cell biology international》2010,34(8):827-835
A phosphatase was purified through a combination of ion‐exchange and hydrophobic chromatography followed by native PAGE from Physarum plasmodia. Recently, we demonstrated that this phosphatase isoform has a hydrolytic activity towards the PMLC (phosphorylated light chain of Physarum myosin II) at pH 7.6. The apparent molecular mass of the purified enzyme was estimated at approximately 50 kDa by means of analytical gel filtration. The enzyme was purified 340‐fold to a final phosphatase activity of 400 pkat/mg of protein. Among the phosphorylated compounds tested for hydrolytic activity at pH 7.6, the enzyme showed no activity towards nucleotides. At pH 7.6, hydrolytic activity of the enzyme against PMLC was detected; at pH 5.0, however, no hydrolytic activity towards PMLC was observed. The K m of the enzyme for PMLC was 10 μM, and the V max was 1.17 nkat/mg of protein. Ca2+ (10 μM) inhibited the activity of the enzyme, and Mg2+ (8.5 μM) activated the dephosphorylation of PMLC. Mn2+ (1.6 μM) highly stimulated the enzyme's activity. Based on these results, we concluded that the enzyme is likely to be a phosphatase with hydrolytic activity towards PMLC. 相似文献
3.
4.
Correlation of structure to antitumor activities of five derivatives of a beta-glucan from Poria cocos sclerotium 总被引:2,自引:0,他引:2
A water-insoluble (1-->3)-beta-D-glucan isolated from fresh sclerotium of Poria cocos was, respectively, sulfated, carboxymethylated, methylated, hydroxyethylated, and hydroxypropylated, to afford five water-soluble derivatives. Their weight-average molecular masses (Mw) and intrinsic viscosities ([eta]) were determined by size-exclusion chromatography combined with laser light scattering (SEC-LLS), LLS, and viscometry in phosphate buffer solution (PBS) at 37 degrees C. The antitumor activities, against Sarcoma 180 tumor cell (S-180) and gastric carcinoma cell strain (MKN-45 and SGC-7901) of the native beta-glucan and the five derivatives, were tested in vitro and in vivo. The Mw values of the five derivatives in PBS were determined to be 3.8 x 10(4), 18.9 x 10(4), 16.0 x 10(4), 76.8 x 10(4), and 224.3 x 10(4), respectively. The high Mw values of the hydroxyethylated and hydroxypropylated derivatives in aqueous solution resulted from aggregation, and their true Mw values obtained in dimethyl sulfoxide were 20.1 x 10(4) and 19.1 x 10(4). The sulfated and carboxymethylated derivatives having DS of 1.0-1.3 show good water solubility, and exist as relatively expanded chains in aqueous solution. Interestingly, the native beta-glucan did not show antitumor activity, whereas the sulfated and carboxymethylated derivatives exhibit significant antitumor activities against S-180 and gastric carcinoma tumor cells. This work showed that good water solubility, relatively high chain stiffness, and moderate molecular mass of the derivatives in aqueous solution contribute beneficial to enhancement of antitumor activity. 相似文献
5.
Pratt RG 《Mycopathologia》2006,162(2):121-131
Germination of sclerotia of Macrophomina phaseolina was quantified by direct microscopic observation following application of experimental treatments in vitro and incubation of sclerotia in soil. To assay germination, pieces of agar containing sclerotia were macerated in dilute,
liquid cornmeal agar on glass slides; thinly spread; and incubated in a saturated atmosphere for 18–22 h. Germinated sclerotia
then were identified by morphological features of germ hyphae. Frequencies of germination were similar in three dilute agar
media. Germination was not affected by air-drying sclerotia for 2 weeks, but it was significantly reduced after 4 weeks and
greatly reduced or eliminated after 6 or 8 weeks. Survival of sclerotia for 14 days in soil was greatest at 50, 75, and 100%
moisture-holding capacity, less at 0 and 25%, and least at 125% (flooded soil). Incorporation of ground poultry litter into
soil at 5% by weight reduced survival of sclerotia after 13 days, and incorporation of litter at 10% nearly eliminated it.
These results indicate that the direct-observation technique may be used to evaluate animal wastes and other agricultural
byproducts for biocontrol activity against sclerotia of M. phaseolina in soil. 相似文献
6.
为探索黏菌的抗氧化活性,以总还原力、DPPH自由基清除率及O2自由基清除率为指标,首次对煤绒菌原质团和菌核甲醇提取物进行抗氧化活性研究。结果表明:煤绒菌原质团和菌核甲醇提取物均有较好的抗氧化活性,当质量浓度为0.8 mg/mL时,二者对O2自由基的清除能力最强,清除率分别为70.39%和86.83%;当质量浓度为0.4 mg/mL时,二者对DPPH自由基的清除能力最强,清除率分别为57.22%和62.91%,通过比较IC50值,菌核粗提物的抗氧化能力略优于原质团。 相似文献
7.
A patient studied at autopsy was found to have a post-operative wound infection with Aspergillus flavus in which there was the formation of fungal structures resembling sclerotia. The ability of Aspergillus to form sclerotia in tissue appears to be rare and is related to the strain of Aspergillus flavus. Since sclerotia are considered as structures capable of withstanding dramatic shifts in the environment, the production of these in tissue may affect the efficacy of antifungal therapy. 相似文献
8.
A water-insoluble (1 → 3)-β-d-glucan (PCSG) isolated from the fresh sclerotium of Poria cocos was carboxymethylated to afford a water-soluble derivative coded as C-PCSG. The carboxymethylated (1 → 3)-β-d-glucan was fractionated to obtain eight fractions according to the nonsolvent addition method. The weight-average molecular mass (Mw), radius of gyration and intrinsic viscosity ([η]) of the fractions were determined by size-exclusion chromatography combined with laser light scattering (SEC-LLS) and viscometry in 0.2 M NaCl aqueous solution at 25 °C. The dependences of [η] and on Mw for C-PCSG were found to be , and (nm), respectively. Analysis of Mw and [η] in terms of the known theories for wormlike chain model yielded 633 nm−1 for molar mass per unit contour length (ML), 5.5 nm for persistence length (q), and 20.2 for characteristic ratio (C∞). These results indicated that C-PCSG exists as a relatively extended flexible chain in 0.2 M NaCl aqueous solution. Therefore, the introduction of the carboxymethyl groups into the β-glucan improved significantly the water solubility and enhanced the stiffness of the chains. 相似文献
9.
10.
土生空球菌(cenococcum geophilum)是一种寄主范围最广、研究最多的外生菌根真菌。本文首次报道了该菌在中国的发现及该菌与火炬松所形成的菌根,全面描述了该菌根的形态学和组织学特征,并对该菌进行了分离培养,描述该菌在纯培养下的特征,对该菌在火炬松上形成的菌根的特征进行了比较,同时讨论了该菌在造林中的重要性。 相似文献