Chelating Effect of Siderophore Desferrioxamine-B on Uranyl Biomineralization Mediated by Shewanella putrefaciens.

In contaminated water and soil, little is known about the role and mechanism of the biometabolic molecule siderophore desferrioxamine-B (DFO) in the biogeochemical cycle of uranium due to complicated coordination and reaction networks. Here, a joint experimental and quantum chemical investigation is carried out to probe the biomineralization of uranyl (UO22+, referred to as U(VI) hereafter) induced by Shewanella putrefaciens (abbreviated as S. putrefaciens) in the presence of DFO and Fe3+ ion. The results show that the production of mineralized solids {hydrogen-uranium mica [H2(UO2)2(PO4)2·8H2O]} via S. putrefaciens binding with UO22+ is inhibited by DFO, which can both chelate preferentially UO22+ to form a U(VI)-DFO complex in solution and seize it from U(VI)-biominerals upon solvation. However, with Fe3+ ion introduced, the strong specificity of DFO binding with Fe3+ causes re-emergence of biomineralization of UO22+ {bassetite [Fe(UO2)2(PO4)2·8(H2O)]} by S. putrefaciens, owing to competitive complexation between Fe3+ and UO22+ for DFO. As DFO possesses three hydroxamic functional groups, it forms hexadentate coordination with Fe3+ and UO22+ ions via these functional groups. The stability of the Fe3+-DFO complex is much higher than that of U(VI)-DFO, resulting in some DFO-released UO22+ to be remobilized by S. putrefaciens. Our finding not only adds to the understanding of the fate of toxic U(VI)-containing substances in the environment and biogeochemical cycles in the future but also suggests the promising potential of utilizing functionalized DFO ligands for uranium processing.

Correlation between changes in flavor compounds and microbial community ecological succession in the liquid fermentation of rice wine.

Microorganisms play an important role in regulating flavor compounds in rice wine, whereas we often don't understand how did they affect flavor compounds. Here, the relations between flavor compounds and microbial community ecological succession were investigated by monitoring flavor compounds and microbial community throughout the fermentation stage of rice wine. The composition of microbial community showed a dynamic change, but 13 dominant bacterial genera and 4 dominant fungal genera were detected throughout the fermentation stages. Saccharomyces presented a strong negative correlation with fungi genera but had positive associations with bacteria genera. Similarly, flavor compounds in rice wine were also showed the dynamic change, and 112 volatile compounds and 17 free amino acids were identified in the whole stages. The alcohol-ester ratio was decreased in the LTF stage, indicating that low temperature boosts ester formation. The potential correlation between flavor compounds and microbial community indicated that Delftia, Chryseobacterium, Rhizopus and Wickerhamomyces were the core functional microorganisms in rice wine. These findings clarified the correlation between changes in flavor compounds and in microbial community in the liquid fermentation of rice wine, and these results have some reference value for the quality improvement and technological optimization in liquid fermentation of rice wine.

Targeted isolation of cytotoxic germacranolide sesquiterpenes from Elephantopus scaber L. using small molecule accurate recognition technology.

Small molecule accurate recognition technology (SMART) is an emerging method for the rapid structural prediction of major constituents from crude extracts and fractions. In the present study, a targeted isolation of an Elephantopus scaber extract by SMART resulted in the obtention of 15 new (1-15) and five known germacranolide sesquiterpenes (16-20). Their structures were assigned by extensively analyzing HRESIMS, NMR, X-ray crystallographic analyses, modified Mosher's method results, and quantum chemical calculate electronic circular dichroism (ECD) spectra. All germacranolide sesquiterpenes were screened to determine their inhibitory effects with two hepatoma cell lines (HepG2 and Hep3B), and compounds 14, 16, 18, 19 and 20 showed significant cytotoxic activities against the HepG2 (IC50, 3.3-9.9 µM) and Hep3B (IC50, 4.5-8.6 µM) cell lines. Further study suggested that 18 can induce the apoptosis of hepatoma cells via mitochondrial dysfunction.

Oxylipin vanillyl acetals from Solanum lyratum.

Four undescribed oxylipin vanillyl acetals with four stereogenic carbons were isolated from the herbs of Solanum lyratum. A comprehensive set of spectroscopic methods were used to elucidate the structures and relative configurations of 1-4. The absolute configurations of the naturally occurring compounds are assigned as 7S, 9'S, 10'S, 11'R at the site of six-membered cyclic acetal attachment by electronic circular dichroism (ECD) calculations and the modified Mosher's method. Compounds 1 and 3 displayed moderate selective inhibition against Hep3B and HepG2 cells, respectively. Further Annexin V-FITC/PI staining assay revealed that 1 and 3 might have inhibitory effects on hepatoma cells through induction of apoptosis.

Sesquiterpenoids from the herbs of Solanum lyratum and their cytotoxicity on human hepatoma cells.

Eleven sesquiterpenoids including four new eudesmane sesquiterpenoids, solanoids A-D (1-4), and seven known compounds (5-11) were isolated from the herbs of Solanum lyratum. By analyzing the UV, MS and NMR data, the gross structures of all isolates were established. The absolute configurations of these new compounds were determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. The in vitro cytotoxicity of all isolates against the hepatocellular carcinoma Hep3B and HepG2 cell lines was evaluated. Among them, compounds 7 and 11 exhibited moderate cytotoxicity against two cell lines.

Assignment of the stereostructures of sesquiterpenoids from the roots of Daphne genkwa via quantum chemical calculations.

Five new guaiane-type sesquiterpenoids were obtained from the roots of Daphne genkwa. Their gross structures were established by extensive spectroscopic analyses. Attempts on the assignment of the relative configurations were unsuccessful when based on the NOESY correlations. Therefore, NMR chemical shift calculations based on the gauge independent atomic orbital (GIAO) method in combination with the statistical method DP4+ were employed to establish their relative configurations. Furthermore, the absolute configurations were determined by comparing the experimental and calculated electronic circular dichroism (ECD) using time-dependent density functional theory (TDDFT). The isolated compounds were screened for their cytotoxicity in vitro against two human hepatocellular carcinoma, HepG2 and Hep3B cell lines.

[Research about formulas for activating blood and resolving stasis Xuesaitong capsule regulate CD117+ hemopoietic stem cell to produce new blood].

OBJECTIVE: To investigate the mechanism that the formulas for activating blood and resolving stasis can regulate hemopoietic stem cell to produce new blood. METHOD: Rats were established animal model of acute cerebral infarction by referencing Olivette' method. They were randomly divided into model group, the group of the high, middle, low dose of the formulas for activating blood and resolving stasis. Each group and then wasrandomly divided into subgroups by 1, 3, 7, 14, 28 d. Xuesaitong capsule was formulated into 20, 40, 60 g x L(-1) with normal saline. The rats were given gavage drugs once a day until the experient ended, and the model group was administrated by intragastrical perfusion of normal saline. ELISA was used to detect the expression of SCF in peripheral blood and bone marrow among different groups at different time points. Flow cytometry was used to observe the changes of CD117 in blood and bone marrow. RESULT: The CD117+ HSC and SCF concentration in peripheral blood and bone marrow of model group were increasing during 1-14 d,there was a peak on the 14th day, then the expression was reducing. CD117+ HSC and SCF concentration rising trend in the group of the high, middle dose of the formulas for activating blood and resolving stasis was preceded model group (P < 0.05). CONCLUSION: Activating blood and resolving stasis can regulate hemopoietic stem cell to produce new blood, and it is through the regulation of CD117+ HSC number to achieve the purpose.