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Chaetominine (CHA), an alkaloid with a biological activity obtained from Aspergillus fumigatus CY018, has strong anticancer activity against the human leukemia cells. However, its physiological and biochemical research is limited by CHA yield in the liquid-state fermentation, which is a problem that urgently needs effective biological solution. In this work, Ca

Chaetominine (CHA), an alkaloid with biological activity produced by Aspergillus fumigatus CY018, has strong anticancer activity against the human leukemia cell. However, its further research for pharmacokinetics is limited by CHA production in submerged fermentation, which is a problem urgently awaiting solutions by effective biological strategies. In this work, Ca2+ and Al3+ exhibited a strong promoting effect on CHA production after multiple metal ions screening. Then, the concentration of Ca2+ and Al3+ and the addition time was optimized. The suitable conditions were 0.5 mM Ca2+ and 0.5 mM Al3+ at 120 h, in which the CHA production reached 58.5 and 49.45 mg/L with optimized condition of Ca2+ and Al3+ respectively. The intermediate metabolites, such as DAHP, chorismate and tryptophan, were increased obviously with addition of Ca2+ and Al3+. The activities of key enzymes of DAHPs, AroAs and TrpCs in CHA biosynthesis pathway were improved by 3.58-, 3.60- and 3.34-folds respectively. Meanwhile, the transcription levels of laeA, dahp, cs, and trpC were upregulated by 3.22-, 12.65-, 5.58- and 6.99-fold respectively by addition of Ca2+ and Al3+. Additionally, the fermentation strategy was successfully scaled up to 5 L reactor, in which CHA production could attain 75.6 mg/L at 336 h. This work demonstrated that Ca2+ and Al3+ co-addition was an effective strategy for increasing CHA production, and the information obtained might be useful to the further improvement of CHA fermentation on large scale.

To explore the response of the soil microbial community to nitrobenzene (NB) exposure in a Spartina marsh, a short-term (45 d) mesocosm study was conducted at three NB concentrations of (10, 50, and 100) mg kg−1. Dry soil, sterile and unsterile controls were also compared. The ability of the microbes to biodegrade NB was studied in an effort to predict the outcome of NB in the mesocosm. The results indicated that a microbial community is capable of doing so. Microbial enumeration and enzyme assays showed that the fluctuations in microbial communities and polyphenol oxidase activities are related to the initial NB concentration. Moreover, cluster analyses through denaturing gradient gel electrophoresis (DGGE) revealed very similar patterns (95.5%) throughout the 45 d term, indicating that the microbial community regenerates when NB is exhausted. Although volatilization and photolysis were the major processes responsible for the reduction in NB in contaminated mesocosms and the microbial community regenerat...

The ESAT-6 protein of Mycobacterium tuberculosis (M. tb) is an important structural and functional protein, which has been known to be involved in the virulence, pathogenesis as well as proliferation of the pathogen; however, how ESAT-6 protein interact with host protein is still unclear. In order to study the function of the M. tuberculosis protein ESAT-6 in the infection process, we searched for host proteins that interact with this secreted mycobacterial protein. Using a yeast two-hybrid system we identii¬ed the ADAM9 (a disintegrin and metalloprotease) protein as a candidate to interact with ESAT-6. This interaction was further coni¬rmed by protein overlay and surface plasmon resonance binding assay using recombinant ESAT-6 and ADAM9, and by GST pull-down analysis of the mycobacterial expressed ESAT-6 and ADAM9. The interaction domains were localized by yeast two-hybrid studies using truncated derivatives of ESAT-6 protein. The C-terminus of ESAT-6 binds to the ADAM9, Thus, the host protein ADAM9 represents a possible cellular receptor for the mycobacterial protein ESAT-6. This is the first report demonstrating the interaction of ADAM9 with a structural protein of M. tb. Key words: ESAT-6 protein, ADAM9 protein, Mycobacterium tuberculosis, yeast two-hybrid, GST pull-down assay, surface plasmon resonance binding

The potential effect of 1,2-dichlorobenzen(1,2-DCB) on microorganisms and enzyme activities was investigated in a flooded wetland soil. The results showed that the number of actinomycetes declined significantly after the treatment of 1,2-DCB at different concentrations, and the amout of bacteria and fungi were significantly decreased in soil samples treated with higher than 200 mg/Kg. 1,2-DCB at over the range of selected concentrations could completely inhibit urease activityin the first 28 days.1,2-DCB at the concentration lower than 100 mg/Kg dried soil stimulated the activity of catalase, while the others showed an inhibition during period of incubation. Results indicated that these two enzymes are sensitive to 1,2-DCB contamination.

The soil microbial assemblages in coastal region is strongly influenced by a wide variety of factors, such as vegetation types and tides. In order to examine the influence of Spartina alterniflora, an exotic species, on the soil microbial assemblages, comparative pairs of experiments were conducted of soil from S. alterniflora marshes and Suaeda salsa marshes for collecting data on soil characteristics, quantity of bacteria, fungi, actinomycetes and azotobacters per gram of dried soil and denaturing gradient gel electrophoresis (DGGE) band profiles. The results revealed that S. alterniflora depressed not only the quantity of microorganisms but also the richness of bacterial community. And, it might suggest that the microbial assemblages were more influenced by vegetation types than tides. Thus, we proposed that the introduction of S. alterniflora into Chinese coastal region should be forbidden.

A bacterium which had the ability of decoloration on Malachite Green was isolated from Zhenjiang printworks and was identified as Pseudomonas aeruginosa. The effects of concentration of the dye concentration、cultural time、cultural temperature and initial pH of cultural medium on the efficiency of decoloration were investigated. The result shows that the optimal cultural conditions was: dye concentration was 50mg∙l-1，cultural time was 72h，cultural temperature was 28℃，initial pH of cultural medium was 7.0.

A bacterium(strain DL-1) capable of growing with1,2-dichlorobenzene as sole carbon and energy sources was isolated from rhizosphere soil in phragmites wetland by using the enrichment culture contaminated with1,2-dichlorobenzene concentration gradient of 20, 40, 60，80, 120, 160 and 200 mg•L-1. It was identified as Bacillus cereus by 16S rDNA gene sequence analysis and the bacterial culture characteristics, carried physiological and biochemical research, the strain was Gram-positive, peritrichous flagellum。 The further degrading characterization reserch proved the strain was a facultative anaerobe and the optimal temperature, pH value and inoculation amount of 1,2-dichlorobenzene degradation were 30℃, pH7.0 and 10%, in 4 d. Respectively , the optimal concentration of 1,2-dichlorobenzene in four days was 120 mg•L-1.