ABSTRACT
This paper was mainly to explore the effects of two Streptomyces strains (S. roche D74 and S. pactum Act12) and their mixed actinomycetes agent on maize growth. Petri dish germination test, sand culture trial and plot trial were performed to determine the biological properties, leaf inducible enzyme activities, photosynthesis, ear characteristics, grain yield and quality of maize after seed soaking with acellular culture filtrate of D74 or Act 12 and seed coating with the mixed actinomycetes agent of two Streptomyces stains. The result showed that the seed soaking treatment significantly contributed to hypocotyls, radical and seedling growth, and increased the leaf inducible enzyme activities of maize seedlings. The 1000-fold dilution of D74 improved hypocotyl length, radicle length, and fibrous root number by 43.4%, 26.4%, and 100.7% (P<0.05), respectively, whereas the undiluted solution of D74 improved leaf polyphenol oxidase (PPO) activity by 40.2% (P<0.05). The 1000-fold dilution of Act12 improved hypocotyl length, radicle length, and fibrous root number by 36.3%, 36.3%, and 117.5% (P<0.05), the total fresh mass and root fresh mass by 31.1% and 36.6%, respectively (P<0.05). The 10-fold and 1000-fold dilutions of Act12 improved leaf PPO activity by 38.1% and 39.5%, respectively (P<0.05). The seed coating treatment showed the following significant effects, compared with the control: 1) Improving the root development. 2) Enhancing the leaf photosynthesis. 3) Improving the ear characteristics and grain yield. 4) Promoteing the grain filling. 5) Improving the leaf inducible enzyme activities. The results indicated that seed coating with the mixed actinomycetes agent of two Streptomyces strains could significantly affect the biological characteristics, photosynthesis and biochemical metabolism of maize seedlings, stimulate root development, promote plant growth, and improve grain yield of maize.
Subject(s)
Plant Development , Streptomyces , Zea mays , Edible Grain , SeedsABSTRACT
Diallyl disulfide (DADS) has been shown to have multi-targeted antitumor activities. We have previously discovered that it has a repressive effect on LIM kinase-1 (LIMK1) expression in gastric cancer MGC803 cells. This suggests that DADS may inhibit epithelial-mesenchymal transition (EMT) by downregulating LIMK1, resulting in the inhibition of invasion and growth in gastric cancer. In this study, we reveal that LIMK1 expression is correlated with tumor differentiation, invasion depth, clinical stage, lymph node metastasis, and poor prognosis. DADS downregulated the Rac1-Pak1/Rock1-LIMK1 pathway in MGC803 cells, as shown by decreased p-LIMK1 and p-cofilin1 levels, and suppressed cell migration and invasion. Knockdown and overexpression experiments performed in vitro demonstrated that downregulating LIMK1 with DADS resulted in restrained EMT that was coupled with decreased matrix metalloproteinase-9 (MMP-9) and increased tissue inhibitor of metalloproteinase-3 (TIMP-3) expression. In in vitro and in vivo experiments, the DADS-induced suppression of cell proliferation was enhanced and antagonized by the knockdown and overexpression of LIMK1, respectively. Similar results were observed for DADS-induced changes in the expression of vimentin, CD34, Ki-67, and E-cadherin in xenografted tumors. These results indicate that downregulation of LIMK1 by DADS could explain the inhibition of EMT, invasion and proliferation in gastric cancer cells.
