间作小麦对西瓜生长及根际土壤酶和微生物的影响

合理的间作可以有效缓解西瓜连作障碍问题,有利于西瓜生产的可持续发展。为了探讨西瓜与小麦间作对西瓜生长的影响,釆用盆栽基质模拟连作土壤,设置小麦和西瓜根系的不同分隔方式(西瓜和小麦根系间作不分隔、用尼龙网分隔、用塑料膜分隔,单种西瓜为对照,),研究不同分隔方式下间作小麦对西瓜根际土壤生物学性状的影响,西瓜定植前接入西瓜专化型尖抱镰刀菌。结果表明,西瓜与小麦根系不分隔处理和用尼龙网分隔处理下西瓜植株的生理参数(叶绿素含量、根系活力、叶片SOD和CAT活性)、土壤酶活性(蔗糖酶和磷酸酶)、土壤细菌的数量,均优于对照和用塑料膜分隔处理;另一方面,西瓜与小麦根系不分隔处理和用尼龙网分隔处理下西瓜植株POD活性、MDA含量、土壤真菌和尖抱镰刀菌的数量均低于对照和用塑料膜分隔处理;但西瓜和小麦根系不同分隔处理和对照处理西瓜植株的生物量(株高和干质量)和土壤放线菌的数量无显著差异。综上,小麦与西瓜间作能增强西瓜植株的生理抗性,提高西瓜根际土壤酶活性,改善根际微生物种群结构。

Expression and Antigen Activity Determination of Human Thyroid Peroxidase in Silkworm and Yeast

In this study,we report the expression of human thyroid peroxidase（TPO） in silkworm larvae and Pichia pastoris GS115. Recombinant TPO is sequentially purified from the hemolymph of infected silkworm larvae and yeast using a Ni-NTA resin kit. The concentration of yield of recombinant TPO is 4.87 mg per thousand larvae and 40.83 mg per liter yeast culture. However,the recombinant TPO produced in silkworm show similar binding ability with the specific anti-TPO serum to standard human TPO purified from insect cells. The lower antigen activity indicates the TPO expressed in yeast is not suitable to be used as the coating antigen in enzyme linked immunosorbent assay（ELISA）. The cost of TPO expressed in B. mori is about 1/4 that of in insect cells,and the cost of TPO purified from silkworm for ELISA is only 1/8 that of TPO produced from Sf9 cells. It indicates the Bm NPV-silkworm expression system is a cost-effectiv e platform for producing TPO with high antigen activity.