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【期刊论文】Exploring novel bioactive compounds from marine microbes
张立新, Lixin Zhang, , Rong An, Jinping Wang, Nuo Sun, Si Zhang, Jiangchun Hu, Jun Kuai
Current Opinion in Mirobiology 2005, 8: 276-281,-0001,():
-1年11月30日
The historical paradigm of the deep ocean as a biological ‘desert’ has shifted to one of a ‘rainforest’ owing to the isolation of many novel microbes and their associated bioactive compounds. Recently, there has been an explosion of information about novel bioactive compounds that have been isolated from marine microbes in an effort to further explore the relatively untapped marine microbes and their secondary metabolites for drug discovery. The microbes are recovered and purified from the ocean by both conventional and innovative isolation methods to obtain those previously thought to be ‘uncultivable’. To overcome the difficulties and limitations associated with cultivation techniques, several DNA-based molecular methods have been developed to bypass the culture-dependent bottleneck. Bioactive compounds isolated using the above strategies have not only shown importance in biotechnological and pharmaceutical applications but have also increased our understanding of the diversity of marine microbiota, ecosystem functions and the exploitable biology.
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【期刊论文】Secretory expression of a heterologous nattokinase in Lactococcus lactis
张立新, Xiaobo Liang, , Lixin Zhang, Jin Zhong, Liandong Huan
Appl Microbiol Biotechnol,-0001,():
-1年11月30日
Nattokinase has been reported as an oral health product for the prevention of atherosclerosis.We developed a novel strategy to express a nattokinase from Bacillus subtilis in a live delivery vehicle, Lactococcus lactis. Promoter PnisZ and signal peptide SPUsp were used for inducible and secretory expression of nattokinase in L. lactis. Western blotting analysis demonstrated that nattokinase was successfully expressed, and about 94% of the enzyme was secreted to the culture. The recombinant nattokinase showed potent fibrinolytic activity, equivalent to 41.7 urokinase units per milliliter culture. Expression and delivery of such a fibrinolytic enzyme in the food-grade vehicle L. lactis would facilitate the widespread application of nattokinase in the control and prevention of thrombosis diseases.
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张立新, Yong Wang, YiGuang Wang, Ju Chu, Yingping Zhuang, Lixin Zhang, , Siliang Zhang
Appl Microbiol Biotechnol (2007) 75: 837-842,-0001,():
-1年11月30日
An S-adenosylmethionine synthetase (SAM-s) gene from Streptomyces spectabilis was integrated along with vector DNA into the chromosome of a Saccharopolyspora erythraea E2. Elevated production of SAM was observed in the recombinant strain Saccharopolyspora erythraea E1. The results from the bioassay showed that the titer of erythromycin was increased from 920 IU ml−1 by E2 to approximately 2,000 IU ml−1 by E1. High performance liquid chromatography (HPLC) analysis revealed that there was a 132% increase in erythromycin A compared with the original strain, while the erythromycin B, the main impurity component in erythromycin, was decreased by 30%. The sporulation process was inhibited, while the SAM-s gene was expressed. The addition of the exogenous SAM also inhibited sporulation and promoted an increase in erythromycin titers.
S-adenosylmethionine synthetase, Erythromycin A, Precision engineering, Saccharopolyspora erythraea
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【期刊论文】Inhibition of Vibrio biofilm formation by a marine actinomycete strain A66
张立新, JianLan You, , XiaoLi Xue, LiXiang Cao, Xin Lu, Jian Wang, LiXin Zhang, ShiNing Zhou
Appl Microbiol Biotechnol (2007) 76: 1137-1144,-0001,():
-1年11月30日
China remains by far the largest aquaculture producer in the world. However, biofilms formed by pathogenic Vibrio strains pose serious problems to marine aquaculture. To provide a strategy for biofilm prevention, control, and eradication, extracts from 88 marine actinomycetes were screened. Thirty-five inhibited the biofilm formation of Vibrio harveyi, Vibrio vulnificus, and Vibrio anguillarum at a concentration of 2.5% (v/v). Thirty-three of the actinomycete extracts dispersed the mature biofilm. Six extracts inhibited the quorum-sensing system of V. harveyi by attenuating the signal molecules N-acylated homoserine lactones’ activity. Strain A66, which was identified as Steptomyces albus, both attenuated the biofilms and inhibited their quorum-sensing system. It is suggested that strain A66 is a promising candidate to be used in future marine aquaculture.
Vibrio biofilm, Quorum sensing, Biocontrol
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【期刊论文】Negative control of apoptosis signal-regulating kinase 1 through phosphorylation of Ser-1034
张立新, Katsunori Fujii, Erinn Hoag Goldman, Hae Ryoun Park, Lixin Zhang, Jing Chen, Haian Fu
Oncogene (2004) 23, 5099-5104,-0001,():
-1年11月30日
Apoptosis signal-regulating kinase 1 (ASK1) is a serine/ threonine kinase that mediates cell stress signaling initiatedby diverse stimuli, such as H2O2 andTNF a. Owing to its critical role in promoting apoptosis, ASK1 activity is highly controlledin cells. Phosphorylation of ASK1 at Thr-845 has been correlatedwith its activation, while phosphorylation at Ser-967 negatively controls its death promoting activity. Here, we report the identification of a novel phosphorylation site at Ser-1034 in the Cterminal regulatory domain of ASK1. Mutating Ser-1034 to an unphosphorylatable Ala ledto increased catalytic activity of ASK1 andenhancedproapop totic function of ASK1. Thus, the proapoptotic function of ASK1 is suppressedin part by phosphorylation at its C-terminal regulatory domain, which may couple upstream survival kinases to the death regulatory machinery.
ASK1, apoptosis, phosphorylation, 14-3-3, kinase, survival signaling
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