Methods for the preparation of a biodesulfurization biocatalyst using Rhodococcus sp.

Several methods to prepare a biodesulfurization (BDS) biocatalyst were investigated in this study using a strain of Rhodococcus sp. 1awq. This bacterium could selectively remove sulfur from dibenzothiophene (DBT) via the "4S" pathway. DBT, dimethylsulfoxide (DMSO), sodium sulphate and mixed sulfur sources were used to study their influence on cell density, desulfurization activity, desulfurization ability, and the cost of biocatalyst production. In contrast to that observed from bacteria cultured in DBT, only partial desulfurization activity of strain 1awq was induced by DBT after cultivation in a medium containing inorganic sulfur as the sole sulfur source. The biocatalyst, prepared from culture with mixed sulfur sources, was found to possess desulfurization activity. With DMSO as the sole sulfur source, the desulfurization activity was shown to be similar to that of bacteria incubated in medium with DBT as the sole sulfur source. The biocatalyst prepared by this method with the least cost could remove sulfur from hydrodesulfurization (HDS)-treated diesel oil efficiently, providing a total desulfurization percent of 78% and suggesting its cost-effective advantage.

[Prokaryotic expression of human vitamin D receptor (hVDR) and its binding activities to Cd and Pb].

Human vitamin D receptor (hVDR) is a potential receptor channel for heavy metals to affect bone metabolism, while to date there is no report about the binding activity between heavy metals and hVDR. This study established a prokaryotic expression of hVDR system, by cloned hVDR-LBD into pGEX-4T-1 vector. Then according to the principle that the nuclear receptor binding with its ligand can be combined with nuclear receptor coactivator 2-bacterial alkaline phosphatase fusion protein (TIF2-BAP), we established a method of p-nitrophenylphosphate-alkaline phosphatase to analyse the effects of chemical on the binding activity between hVDR and TIF2-BAP. Using this method, we studied the binding activities between hVDR and TIF2-BAP after exposure of cadmium and lead. The results showed that the binding activities significantly increased to 3.95 and 4.39 times that of the control after exposure of 100 micromol/L and 1 000 micromol/L cadmium chloride (CdCl2), and the binding activities significantly increased to 2.29 and 3.52 times that of the control after exposure of 100 micromol/L and 1 000 micromol/L lead acetate (PbAc2), respectively. These results indicate that cadmium and lead can mimic the activity of 1,25-(OH)2D3, disrupt the normal function of hVDR receptor channel, which may be the underlying mechanism of abnormal bone metabolism and osteoporosis caused by cadmium and lead.

[Effects of climate change on photosynthesis of Diospyros kaki under different soil moisture conditions].

Taking two-year-old Diospyros kaki as test material, this paper studied the effects of high CO2 concentration (700 micromol x mol(-1)), high temperature (5 degrees C higher than the mean daily temperature); and their combination on the net photosynthesis rate (Pn), evapotranspiration (Tr), stomatal conductance (Gs), water use efficiency (WUE), chlorophyll content, Fv/Fm, and Fv/Fo under different soil moisture conditions, with the ambient air temperature and CO2 concentration (380 micromol x mol(-1)) as the control. Under all test soil moisture conditions, the combination of high CO2 concentration and high temperature decreased the Tr and Gs, but increased the WUE. This combination increased the Pn when the soil moisture content was 75%-85% and 55%-65% of field capacity, but decreased the Pn when the soil moisture content was 35%-45%. High CO2 concentration increased the Pn and WUE but decreased the Gs and Tr under all test soil moisture conditions. The effects of high temperature and its combination with high CO2 concentration on the WUE depended on soil moisture condition, with the WUE increased with increasing soil moisture content. Comparing with the control, high CO2 concentration also increased the leaf Chla, Chlb, Chl (a + b), and Car concentrations and the Fv/Fm and Fv/Fo values, relieved the water stress, and increased the stress-resistance of D. kaki.

[Gene cloning, sequence analysis and tissue expression of estrogen-related receptor alpha (Erralpha) in Japanese medaka and its transcriptional responses after differential EDCs exposure].

Endocrine disrupting chemicals (EDCs) can bind or block nuclear receptors in the body and subsequently affect growth, development and reproduction of fish. Estrogen-related receptors (ERRs), belonging to the nuclear receptor superfamily, have been implicated in diverse physiological processes in estrogen signal pathway in mammals, while little is known about them in fishes. Complete mRNA sequence of ERRalpha from medaka (Oryzias latipes) was cloned, and the sequence is similar to those of other vertebrates, especially that the DNA-binding domain (DBD) of ERRalpha is highly conserved among the vertebrates (97.4%-100% sequence identities) and the ligand-binding domain (LBD) of medaka ERRalpha is 66.4%-67.0% sequence identities with those of mammals. The DBD of medaka ERRalpha is of the same length and has high sequence identity with those of estrogen receptor (ERalpha and ERbeta) and androgen receptor (ARalpha and ARbeta) of medaka, but much difference was found between the LBD of medaka ERRalpha with those of ERalpha, ERbeta, ARalpha and ARbeta. ERRalpha gene is located in chromosome 14 and is consisted of 5 exons. The expressions of ERRalpha in different tissues and the transcriptional responses of ERRalpha in testis of medaka exposed differential EDCs were studied by quantitative real-time RT-PCR. ERRalpha is expressed at apparently high levels in gonad, brain, eye, spleen and intestine, though it was broadly expressed in tissues. Significant transcriptional difference was found between testis and ovary, implying ERRalpha would be involved in sex differentiation and gonad development in fish. After 3 weeks exposure of medaka to 200 ng/L ethynylestradiol (EE2), 200 ng/L estrone (E1), 200 ng/L diethylstilbestrol (DES), 100 microg/L atrazine (AT) and 200 ng/L 17beta-estradiol (E2), transcripts of ERRalpha were significantly decreased to 0.54, 0.56, 0.61, 0.63 and 0.65 of control (p < 0.05) in the testes, respectively. And those in the 1 microg/L tributyltin (TBT) and 1 microg/L triphenyltin (TPT) exposure groups were up-regulated to 1.34 and 1.35 folds of control (p > 0.05), respectively. These results suggested that ERRalpha would take actions in the disruption of sex differentiation and gonad development in fish by EDCs. In addition, no multiple steroid hormone-response element half-sites was found in medaka, which were reported in the upstream of ERRalpha gene in mammals, indicating there would be different regulation patters of ERRalpha between teleost and mammal.

[Evaluation of estrogenic activity for nonylphenol using quantitative real-time RT-PCR method].

It has been demonstrated that nonylphenol (NP) exerts estrogenic activity. Quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) was used to study the VTG-I , VTG-II , CHG-H and CHG-L genes expression in the liver of juvenile medaka exposed to NP at 1, 10, 50, 100 microg/I. for 60 days. The results show that the VTG-I , VTG-II, CHG-H and CHG-L genes expression in the liver of juvenile medaka are induced even at 1 microg/L, significantly. It should be noted that the lowest-observed-effect concentration (LOECs) based on the hepatic vitellogenin (VTG) induction is about 1 microg/L, suggesting that quantitative real-time RT-PCR can detect the estrogenic activity of NP at relatively low concentration, and there is a potential application in evaluating the estrogenic activity of NP in aquatic environment.