Human salivary gland stem cells ameliorate hyposalivation of radiation-damaged rat salivary glands

Salivary function in mammals may be defective for various reasons, such as aging, Sjogren''s syndrome or radiation therapy in head and neck cancer patients. Recently, tissue-specific stem cell therapy has attracted public attention as a next-generation therapeutic reagent. In the present study, we isolated tissue-specific stem cells from the human submandibular salivary gland (hSGSCs). To efficiently isolate and amplify hSGSCs in large amounts, we developed a culture system (lasting 4–5 weeks) without any selection. After five passages, we obtained adherent cells that expressed mesenchymal stem cell surface antigen markers, such as CD44, CD49f, CD90 and CD105, but not the hematopoietic stem cell markers, CD34 and CD45, and that were able to undergo adipogenic, osteogenic and chondrogenic differentiation. In addition, hSGSCs were differentiated into amylase-expressing cells by using a two-step differentiation method. Transplantation of hSGSCs to radiation-damaged rat salivary glands rescued hyposalivation and body weight loss, restored acinar and duct cell structure, and decreased the amount of apoptotic cells. These data suggest that the isolated hSGSCs, which may have characteristics of mesenchymal-like stem cells, could be used as a cell therapy agent for the damaged salivary gland.     

米曲霉固态发酵产淀粉酶条件优化的研究

以米曲霉A—l为出发菌株,在研究培养基加水量、温度、无机盐和培养时间等单因素的基础上,采用正交试验方法进行固态发酵产淀粉酶条件优化研究,并对正交试验结果进行了验证。试验结果表明,该菌株固态发酵产淀粉酶的最优条件为：加水量10mL,麸皮与豆饼粉的比例为8：2,MgS047H：0添加量为1％,在30℃发酵84h,酶活达269U／g。     

磁场对洋葱鳞茎萌发及酶活性的影响

分别用四个强度和时间的恒定磁场对紫皮洋葱鳞茎进行处理.结果表明:以1500GS、20分钟的发芽率最低(即抑制洋葱鳞茎发芽效果最好),在磁处理后60天时,其发芽率为28.07%,比CK低21.05%.不同磁场强度和处理时间对洋葱鳞茎总淀粉酶活性,IAA氧化酶活性的影响是不同的.其中以1500GS、20分钟的总淀粉酶活性最低,IAA氧化酶活性最高,从而对洋葱鳞茎的发芽起到一定的抑制作用,这与1500GS、20分钟的发芽率最低是一致的.     

麦芽糖淀粉酶CDS 1-3在淀粉糖化过程中的作用分析

为探究多糖相互作用对淀粉糖化速率的影响，本研究使用较传统麦芽糖淀粉酶更具支链淀粉水解能力的麦芽糖淀粉酶CDS 1-3，将其与α-淀粉酶及糖化酶协同进行淀粉糖化，并对糖化液进行还原糖测定以及高效液相色谱分析。结果表明：反应到30 min时，CDS 1-3作用效果最明显，相比于Control组，CDS 1-3组糖化液的葡萄糖当量(Dextrose Equivalent,DE)值提高了4.51%。随着反应的进行，DE值提高速率降低。反应到60 min时，DE值提高了1.17%；反应到90 min时，DE值提高了2.12%。高效液相色谱结果显示，在整个反应过程中，CDS 1-3组葡萄糖和麦芽糖的产量始终高于Control组，说明CDS 1-3可有效加快木薯淀粉糖化速率，可应用于淀粉工业中。