[Effects of electron acceptor and light on the abundance of microbial function gene related to soil CH4 emission]. / ç”µå­å—ä½“å’Œå ‰ç §å¯¹åœŸå£¤CH4æŽ’æ”¾ç›¸å ³å¾®ç”Ÿç‰©åŠŸèƒ½åŸºå› ä¸°åº¦çš„å½±å“.

To explore the effects of different electron acceptors on soil methane emission and responses of soil microorganisms to different light conditions, a strict anaerobic 20-day incubation experiment was conducted with eight treatments: darkness + Fe3+ (DF); darkness + NO3- (DN); darkness +SO42- (DS); darkness + distilled water (DCK); light + Fe3+ (LF); light + NO3- (LN); light +SO42- (LS); light + distilled water (LCK). The changes of methane concentration in the anaerobic incubation flask and the variation of the abundance of bacteria, archaea, fungi and six soil functional genes were analyzed. Results showed that soil methane emission under NO3-, SO42- addition and control (CK) was significantly lower under light conditions than dark, except the Fe3+ treatment. DN, DCK and LF treatments had the highest abundance of bacteria, fungi and archaea genes, respectively. The gene abundance of methanogenic mcrA, sulfate-reducing bacteria Dsr, and carbon-fixing CbbL were significantly up-regulated in the LF, while that of methanotrophs pmoA, iron-reducing bacteria Geo, and denitrifying bacteria nosZ were significantly up-regulated in the LN, DCK and LCK, respectively. Results of Pearson correlation and RDA analysis showed that CH4 emission was significantly positively correlated with CO2 concentration, pH, ammonium-nitrogen, and total N contents, and negatively correlated with N2O concentration, Eh, nitrate, and total C contents. Under dark condition, methane emission was positively correlated with archaea and pmoA genes abundance, and negatively correlated with other genes abundance. Under light condition, methane emission was negatively correlated with the abundance of soil microbe and functional genes. In general, methane emission under light condition was significantly lower than that under dark condition (except for the Fe3+ treatment). These results showed that it was helpful to reduce methane emission under light condition, but the increase or decrease of methane emission was closely related to the type of electron acceptors and the functional responses of soil micro-organisms.

Isolation and characterization of endophytic huperzine A-producing fungi from Huperzia serrata.

Huperzia serrata is a producer of huperzine A (HupA), a cholinesterase inhibitor (ChEI). Over 120 endophytic fungi were recovered from this plant and screened for Hup-A and nine were found. These nine represented seven different fungal genera with the most significant producer being Shiraia sp. A total of 127 endophytic fungi isolates obtained from the root, stem, and leaf segments of H. serrata were grouped into 19 genera based on their morphological traits and sequence analysis of the internal transcribed spacers (ITS1-5.8S-ITS2), indicating endophytic fungi in H. serrata are diverse and abundant. Aspergillus, Podospora, Penicillium, Colletotrichum, and Acremonium were the frequent genera, whereas the remaining genera were infrequent groups. Overall, 39 endophytic fungi isolates showed acetylcholinesterase (AChE) inhibition in vitro. Nine endophytic fungi isolates from seven distinct genera were capable of producing HupA verified by thin-layer chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). Among the HupA-producing fungi, the yield of HupA produced by the Shiraia sp. Slf14 was 327.8 µg/l in potato dextrose broth, and the fungal HupA was further validated by mass spectrometry (ESI-MS). The present study demonstrated that H. serrata was a fascinating fungal reservoir for producing HupA and other ChEIs.

[Detection of cytokeratin20 mRNA in peripheral blood from colonic cancer patients by fluorescence quantitative polymerase chain reaction].

OBJECTIVE: To investigate the expression level of cytokeratin20 mRNA (CK20 mRNA) of cancer cells in peripheral blood from colorectal cancer patients, detected by fluorescence quantitative polymerase chain reaction (FQ-PCR), and to evaluate its clinical value. METHODS: To systemically study the reproducibility, quantitative range and amplification efficiency of CK20 mRNA detection by FQ-PCR, analyze and compare the result consistency with conventional RT-PCR and immunohistochemistry, separately. The expression level of CK20 mRNA of cancer cells in peripheral blood was examined in 136 colorectal cancer cases with or without hepatic metastasis. RESULTS: The within-run and between-run CV of FQ-PCR to assay CK20 mRNA were 3.6% and 5.3%, respectively, quantitative range was from 10(3) copies/ml to 10(8) copies/ml and amplification efficiency was 87.4%. Comparing with traditional RT-PCR and immunohistochemistry, the Kappa value was 0.87 and 0.83, respectively. The expression level of CK20 mRNA of cancer cells in peripheral blood from colorectal cancer patients was (3.52 +/- 1.47) x 10(4) copies/ml, and the expression positive rate was 48.5%. None was found among the 75 cases in the control group. The positive rate of CK20 mRNA of cancer cells in peripheral blood was 9.5%, 25.0%, 48.8% and 87.5% in the patients at Dukes stage A, B, C and D, respectively (P < 0.05). The positive rate of CK20 mRNA was 87.5% in patients with hepatic metastasis and 32.3% in patients without hepatic metastasis (P < 0.05). CK20 mRNA showed a tendency to decline in 35 cases of colorectal cancer within the 1st, 3rd and 5th week after operation. There was no difference among the data of pre-operation cases and on the 1st, 3rd week (P > 0.05), but a significant difference between pre-operation and the 5th week (P < 0.05). CONCLUSION: FQ-PCR is a rapid and sensitive method for quantitating CK20 mRNA. The expression of CK20 mRNA of cancer cells in peripheral blood from colorectal cancer patients has a correlation with recurrence and metastasis of the tumors. Detection of CK20 mRNA is helpful to monitor hematogenous dissemination of colorectal cancers.