Effective extraction of elastase from Bacillus sp. fermentation broth using aqueous two-phase system

This paper presents the evaluation of an aqueous two-phase system （ATPS） for extracting elastase produced by Bacillus sp. EL31410. The elastase and cell partition behavior in polyethylene glycol （PEG）/salt systems was investigated. The suitable system for elastase extraction was PEG/KHEPO4-KEHPO4, in which elastase is mainly partitioned into the PEG-rich phase, while the cells remained in the other phase. The influence of defined system parameters （e.g. PEG molecular mass, pH, NaCl addition） on the partitioning behavior of elastase is described. The concentration of phase forming components, PEG and KHEPO4-KEHPO4, was optimized for elastase recovery by means of response surface methodology, and it was found that they greatly influenced extraction recovery. The optimal ATPS was 23.1% （w/w） PEG 2000 and 11.7% （w/w） KHEPO4-KEHPO4. The predicted recovery was about 89.5%, so this process is suggested to be a rapid and convenient method for elastase extraction.

Response of ATP sulfurylase and serine acetyltransferase towards cadmium in hyperaccumulator Sedum alfredii Hance

We studied the responses of the activities of adenosine-triphosphate (ATP) sulfurylase (ATPS) and serine acetyltransferase (SAT) to cadmium (Cd) levels and treatment time in hyperaccumulating ecotype (HE) Sedum alfredii Hance, as compared with its non-hyperaccumulating ecotype (NHE). The results show that plant growth was inhibited in NHE but promoted in HE when exposed to high Cd level. Cd concentrations in leaves and shoots rapidly increased in HE rather than in NHE, and they became much higher in HE than in NHE along with increasing treatment time and Cd supply levels. ATPS activity was higher in HE than in NHE in all Cd treatments, and increased with increasing Cd supply levels in both HE and NHE when exposed to Cd treatment within 8 h. However, a marked difference of ATPS activity between HE and NHE was found with Cd treatment for 168 h, where ATPS activity increased in HE but decreased in NHE. Similarly, SAT activity was higher in HE than in NHE at all Cd treatments, but was more sensitive in NHE than in HE. Both ATPS and SAT activities in NHE leaves tended to decrease with increasing treatment time after 8 h at all Cd levels. The results reveal the different responses in sulfur assimilation enzymes and Cd accumulation between HE and NHE. With increasing Cd stress, the activities of sulfur assimilation enzymes (ATPS and SAT) were induced in HE, which may contribute to Cd accumulation in the hyperaccumulator Sedum alfredii Hance.

人参四逆汤及其有效成分对戊巴比妥钠所致心肌细胞损伤模型的保护作用

目的:探讨人参四逆汤及其有效成分对戊巴比妥钠所致心肌细胞损伤的保护作用及其机制。方法:H9C2细胞经传代培养后,分别给予人参皂苷Rb20.01,0.1,1μmol·L^-1,Re0.01,0.1,1μmol·L^-1,异甘草素(isoliquiritigenin,ISL)20,40,80μmol·L^-1,甘草次酸(glycyrrhetinic acid,GA)10,20,40μmol·L^-1,人参四逆汤10,100,400mg·L^-1,作用4h,经0.1%的戊巴比妥钠作用30min后,检测细胞存活率,乳酸脱氢酶(lactate dehydrogenase,LDH),脂质过氧化物丙二醛(malondialdehyde,MDA),Na^+-K^+-三磷酸腺苷(ATP)酶,Ca^2+ -ATP酶活性,同时采用实时荧光定量聚合酶链式反应(Real-time PCR)检测过氧化物酶体增殖活化受体共激活因子-1α(peroxisome proliferative activated receptor,PGC-1α),B淋巴细胞瘤-2相关X蛋白(Bax),半胱氨酸蛋白酶-3(Caspase-3)mRNA的表达情况。结果:人参四逆汤及其有效成分对心衰细胞模型有保护作用,与正常组比较,模型组细胞存活率显著下降,LDH,MDA含量显著升高,Na^+ -K^+ -ATP酶活性升高,Ca^2+ -ATP酶活性显著降低,PGC^-1α mRNA表达下调,Bax,Caspase-3 mRNA表达(P<0.01),证明模型成立。与模型组比较,各给药组显著升高细胞存活率,降低LDH,MDA含量,抑制Na^+ -K^+ -ATP酶活性,提高Ca^2^+ -ATP酶活性,上调PGC^(-1)αmRNA表达,抑制Bax,Caspase-3mRNA表达(P<0.05,P<0.01)。结论:人参四逆汤及其有效成分对心衰细胞模型有显著保护作用,且其作用机制与抗氧化,改善线粒体能量代谢,抑制线粒体凋亡途径有关。