RESUMO
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.
Assuntos
Desenvolvimento Vegetal , Streptomyces , Zea mays , Grão Comestível , SementesRESUMO
OBJECTIVE: To investigate the effect of alantolactone on perliferation and apoptosis of multiple myeloma (MM) RPMI-8226 cells, and to explore its possible mechism in vitro and in vivo. METHODS: The RPMI-8226 cells were treated with alantolactone (1, 2.5, 5, 7.5 and 10 µmol/L) for 48 h, cell viability was detected by CCK-8 assay and the value of IC50 was calculated; The RPMI-8226 cells were treated with alantolactone (2.5, 5 and 7.5 µmol/L) for 48 h, the apoptotic rate was detected by flow cytmetry with Annexin V/PI staining; the expression level of cleaved caspase-3 and phosphorylation of ERK were measured by Western blot; the nude mice was used to further confirm the proapoptotic effect of alantolactone on MM cells in vivo. RESULTS: The alantolactone inhibited RPMI-8226 cell viability remarkably with a dose-dependent manner; the IC50 value of RPMI-8226 cells at 48 h was 4.32 ± 0.15 µmol/L; the apoptotic rate increased observably with a dose-dependent manner; the levels of cleaved-caspase-3 increased and the phosphorylation of ERK decreased significantly; as compared to control, the volum of tumor was much smaller, the expression levels of Ki67 and p-ERK decreased. CONCLUSION: The alantolactone can efficiently inhibit the proliferation and induce the apoptosis of multiple myeloma RPMI-8226 cells in vitro and in vivo through inhibiting the activation of ERK signal pathway.