Vol 2, No 1: (In Publishing)





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Table of Contents

Original Research Article

by Linkai Ji
21 Views, 5 PDF Downloads

Telomerase is a kind of nuclear protease with special reverse transcriptase activity, which can repair the damage of telomere at the end of chromosome caused by cell division and differentiation. The research shows that telomerase activity is related to cell aging, cell proliferation and a series of related diseases, so the detection method of telomerase activity is of great significance for the study of cell immortalization, aging, cancer and other diseases. This paper introduces the significance of detection of telomerase activity and the limited extension method which has the characteristics of sensitivity, high efficiency, low cost, easy quantification and low operation difficulty.


Original Research Article

by Jun Cao, Xin Tang, Hao Zhang, Wei Chen, Haiqin Chen
6 Views, 4 PDF Downloads

Mortierella alpina is an oil-producing microorganism for the commercial production of arachidonic acid. Its lipids are mainly stored in the form of triglycerides. However, there have been no reports on the functional properties of the diacylglycerol acyltransferase 1 (DGAT1), which is the key rate-limiting enzyme in the triglyceride synthesis pathway in this strain. In order to study the function of DGAT1 in the synthesis of triglyceride of Mortierella alpina, this study screened the homologous gene Madgat1 by homology alignment, and identify its protein expression and its impact on lipid synthesis by heterologous expression in S. cerevisiae. As a result, Madgat1 showed the function of catalyzing the synthesis of TAG. The TAG content of the recombinants was increased by 7.2 times and the total fatty acid content was increased by 2.4 times. The results provide theoretical support for further improving the lipid production of oil-producing microorganis ms such as Mortierella alpina by genetic engineering.

 

Mortierella alpina is an oil-producing microorganism for the commercial production of arachidonic acid. Itslipids are mainly stored in the form of triglycerides. However, there have been no reports on the functional propertiesof the diacylglycerol acyltransferase 1 (DGAT1), which is the key rate-limiting enzyme in the triglyceride synthesispathway in this strain. In order to study the function of DGAT1 in the synthesis of triglyceride of Mortierella alpina, thisstudy screened the homologous gene Madgat1 by homology alignment, and identify its protein expression and its impacton lipid synthesis by heterologous expression in S. cerevisiae. As a result, Madgat1 showed the function of catalyzingthe synthesis of TAG. The TAG content of the recombinants was increased by 7.2 times and the total fatty acid contentwas increased by 2.4 times. The results provide theoretical support for further improving the lipid production of oilproducingmicroorganis ms such as Mortierella alpina by genetic engineering.

Original Research Article

by Yanjun Xia, Hong Zong, Xinyao Lu, Gebin Zhu, Huagen Xu, Jing Zhang
2 Views, 3 PDF Downloads

 In order to obtain soybean peptide with high antioxidant activity, soy protein isolate (SPI) was pretreated by extrusion, and then alcalase was used to carry out further hydrolysis to prepare soybean antioxidant polypeptides. The results showed that extrusion pretreatment destroyed the spatial structure of SPI, such as α-helix disappeared, random curl appeared, β -sheet content decreased and β-turn content increased, making the structure more disordered, which was beneficial to the hydrolysis of protease. The optimum conditions for the preparation of soybean anti-oxidation polypeptides (ESPIH) by extrusion processing combined with enzymatic hydrolysis were as follows: substra te concentration was set to 70 mg/ml, temperature was set to 40 ℃, pH was set to 9, substrate-enzyme (S:E, g:g) was set to 4:100, time was set to 20 min, and the scavenging rate of DPPH was up to 90.81%. The scavenging rates of DPPH, superoxide radicals, and hydroxyl radicals and total reducing power of ESPIH were significantly higher than SPIH at different concentrations. The above-mentioned results indicated that extrusion pretreatment could change the secondary structures of soy protein and was an effective mean to enhance the antioxidant activity of soybean peptide.

 


Original Research Article

by Lei Yang, Yonglei Ying, Naiqun Zhang
2 Views, 3 PDF Downloads

 Steam explosive material of straw contained a large number of fermentation inhibitors, which could inhibit the growth of microorganisms and reduce fermentation yield. It needed to be removed before enzymatic hydrolysis. The effects of different detoxification and washing processes on the fermentation of heterotrophic chlorella were studied in this paper. The results showed that the treatment of steam explosive by water-elution had no significant effect on the normal growth and metabolism of heterotrophic chlorella. On this basis, multiple washing and water consumption (straw: water is 1:9) were used. After detoxification, the dry weight of heterotrophic chlorella reached 9.53 g/L at the end of fermentation, which was only 2.41% lower than that of the Effect on the fermentation results of heterotrophic by detoxification technology of straw enzymatic hydrolysatecontrol group, and could meet the needs of use.

 


Original Research Article

by Yaquan Cui, Shoushuai Feng, Hailin Yang
2 Views, 6 PDF Downloads

High concentrations of copper ions in the leaching environment would affect the normal growth of the leached microorganisms. In this paper, the physiological and transcript levels of Acidithiobacillus caldus under copper stress were analyzed to explore its mechanism of resisting copper stress. The growth of the cells under copper stress was inhibited, and more EPS was produced, more glutamic acid, glycine and cysteine were secreted. The content of unsaturated fatty acids and cyclopropane fatty acids increased, and the level of antioxidants enhanced. 140 genes were significantly differentially expressed under the stress of 1 g/L copper ions while 250 genes under the stress of 3 g/L copper ions. These genes were primarily involved in cellular metabolism, signal transduction, and cell movement. In this paper, the physiological and transcriptional responses of Acidithiobacillus caldus under copper stress were investigated. The results can provide a reference for finding strategies to improve copper resistance.