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11.
铆钉菇菌丝体液体培养条件及产胞外多糖的研究 总被引：3，自引：0，他引：3
[目的]为食用菌液体培养和胞外多糖的研究提供基础。[方法]研究铆钉菇菌丝体的最佳液体培养条件,并对其产胞外多糖的情况进行测定。[结果]铆钉菇菌丝体深层发酵适宜的培养基组成为:蔗糖20 g/L、酵母浸膏2 g/L、K2HPO40.5 g/L、MgSO40.5g/L、Vc 0.001 g/L,适宜培养温度28℃,pH值7.0。铆钉菇菌丝体液体培养7 d,菌丝体干重为28.0 g/L,胞外多糖产量为3.27 g/L。[结论]铆钉菇菌丝体液体培养可很好地生长,并产生较多的胞外多糖。 相似文献
12.
十字花科黑腐病菌（Xanthomonas campestris pv.campestris,简称Xcc）能够产生大量的胞外多糖。胞外多糖商品名又称为黄原胶,具有广泛用途,在食品生产中可作为添加剂使用。为了得到不含黄色素的黄原胶,我们采用转座子EZ-Tn5随机插入诱变的方法对8004菌株进行突变,获得了一株不产黄色素的突变体。通过对突变体的转座子EZ-Tn5插入位点进行分析,发现该突变体是由于编号为XC_4097的基因被插入突变后衍生而来。同源性分析表明XC_4097编码一种脂质酰基转移酶,它与脂质的合成有关。采用同源双交换方法构建XC_4097基因的缺失突变体。通过对野生菌、突变体以及功能回补体的表型分析进一步证实了XC_4097基因功能的丧失只影响黑腐病菌黄色素的合成,而不影响细菌生长以及胞外多糖的合成。这为工业上生产无黄色素的黄原胶提供了应用基础。 相似文献
13.
Some flavonoids present in root exudates are inducers of nod genes in rhizobia-legume symbioses. They also induce changes in the molecular weight, structure, and level of secretion of
some extracellular proteins, exopolysaccharides (EPS) and lipopolysaccharides. We showed that incubation of Sinorhizobium fredii USDA 257 with four flavonoids (genistein, naringenin, chrysin, and apigenin) promoted its growth in the late log phase. By
contrast, only genistein accelerated the growth of S. fredii TU 6 under the same conditions. When both strains were incubated with naringenin the synthesis of EPS decreased. However,
this compound increased the secretion of extracellular proteins in the early log phase. The specific mode of action of naringenin
is still not clear.
Received: 1 July 1998 相似文献