Establishment of cytochrome P450 3A4 and glutathione S-transferase A1-transfected human hepatoma cell line and functional analysis.

This study aimed to enhance the drug metabolism function of the human hepatoma cell line C3A and to explore the related significance for patients with severe liver disease. The important liver phase I and phase II drug metabolism enzymes, cytochrome P450 3A4 (CYP 3A4) and glutathione S-transferase A1 (GST A1), were constructed into a double expression vector and then transfected into C3A cells. Furthermore, in order to increase the expression of CYP 3A4 and GST A1, they were optimized according to human optimal codons. Another double-expression vector, pBudCE4.1-optimized CYP 3A4-optimized GST A1, was constructed and then transfected into C3A to establish a stable cell line. The drug metabolism function of C3A was evaluated. Sequence determination and analysis results showed that the recombinant plasmid pBudCE4.1-CYP 3A4-GST A1 met the application standard and its transfection was successful. The expression and activity of CYP 3A4 and GST A1 in unoptimized C3A cells were higher than those in blank C3A cells. Unoptimized C3A had a better drug metabolism function. Although some C3A cells transfected with pBudCE4.1-optimized CYP 3A4-optimized GST A1 survived, they grew slowly, and were therefore not applicable in clinical practice. Unoptimized C3A is superior to blank C3A in drug metabolism, and could be applied in the bioartificial liver support system as a new material.

Nitrogen losses in anoxic marine sediments driven by Thioploca-anammox bacterial consortia.

Ninety per cent of marine organic matter burial occurs in continental margin sediments, where a substantial fraction of organic carbon escapes oxidation and enters long-term geologic storage within sedimentary rocks. In such environments, microbial metabolism is limited by the diffusive supply of electron acceptors. One strategy to optimize energy yields in a resource-limited habitat is symbiotic metabolite exchange among microbial associations. Thermodynamic and geochemical considerations indicate that microbial co-metabolisms are likely to play a critical part in sedimentary organic carbon cycling. Yet only one association, between methanotrophic archaea and sulphate-reducing bacteria, has been demonstrated in marine sediments in situ, and little is known of the role of microbial symbiotic interactions in other sedimentary biogeochemical cycles. Here we report in situ molecular and incubation-based evidence for a novel symbiotic consortium between two chemolithotrophic bacteria--anaerobic ammonium-oxidizing (anammox) bacteria and the nitrate-sequestering sulphur-oxidizing Thioploca species--in anoxic sediments of the Soledad basin at the Mexican Pacific margin. A mass balance of benthic solute fluxes and the corresponding nitrogen isotope composition of nitrate and ammonium fluxes indicate that anammox bacteria rely on Thioploca species for the supply of metabolic substrates and account for about 57 ± 21 per cent of the total benthic N2 production. We show that Thioploca-anammox symbiosis intensifies benthic fixed nitrogen losses in anoxic sediments, bypassing diffusion-imposed limitations by efficiently coupling the carbon, nitrogen and sulphur cycles.

Denitrification as the dominant nitrogen loss process in the Arabian Sea.

Primary production in over half of the world's oceans is limited by fixed nitrogen availability. The main loss term from the fixed nitrogen inventory is the production of dinitrogen gas (N(2)) by heterotrophic denitrification or the more recently discovered autotrophic process, anaerobic ammonia oxidation (anammox). Oceanic oxygen minimum zones (OMZ) are responsible for about 35% of oceanic N(2) production and up to half of that occurs in the Arabian Sea. Although denitrification was long thought to be the only loss term, it has recently been argued that anammox alone is responsible for fixed nitrogen loss in the OMZs. Here we measure denitrification and anammox rates and quantify the abundance of denitrifying and anammox bacteria in the OMZ regions of the Eastern Tropical South Pacific and the Arabian Sea. We find that denitrification rather than anammox dominates the N(2) loss term in the Arabian Sea, the largest and most intense OMZ in the world ocean. In seven of eight experiments in the Arabian Sea denitrification is responsible for 87-99% of the total N(2) production. The dominance of denitrification is reproducible using two independent isotope incubation methods. In contrast, anammox is dominant in the Eastern Tropical South Pacific OMZ, as detected using one of the isotope incubation methods, as previously reported. The abundance of denitrifying bacteria always exceeded that of anammox bacteria by up to 7- and 19-fold in the Eastern Tropical South Pacific and Arabian Sea, respectively. Geographic and temporal variability in carbon supply may be responsible for the different contributions of denitrification and anammox in these two OMZs. The large contribution of denitrification to N(2) loss in the Arabian Sea indicates the global significance of denitrification to the oceanic nitrogen budget.

[Comparative study on clinical features of 215 patients with acute and subacute severe hepatitis.].

BACKGROUND: To analyze the clinical features of acute severe hepatitis (ASH) and subacute severe hepatitis (SSH) by comparison analysis. METHODS: The clinical features of 215 cases with ASH and SSH from 1995 to 2005 were retrospectively analyzed by using chi-test, t-test and regression analysis. RESULTS: The most common cause of ASH or SSH was hepatitis B virus (HBV) infection (>30%). Anti-tuberculosis therapy was the main cause of drug-induced ASH or SSH. The incidences of hepatic encephalopathy were 78.13% and 43.05% respectively (P less than 0.001). Prothrombin activity was less than 20% and less than 30%, respectively in cases with ASH and SSH. The most common complications of ASH were hepatic encephalopathy, imbalance of electrolyte and cerebral edema, and that of SSH were ascites, imbalance of electrolyte and hepatic encephalopathy. Prothrombin time, ratio of WBC and neutrophil count were positively related to case fatality of ASH or SSH. Prothrombin activity and total cholesterol (TC) were negatively correlated with fatality of ASH or SSH. Total bilirubin, blood ammonia and creatinine were also positively correlated with fatality of SSH; chlolinesterase, triglyceride, PLT, albumin were negatively correlated with fatality of SSH. CONCLUSION: ASH and SSH are two different entities because of obvious differences in the ages of suffering, the incidence and occurring time of hepatic encephalopathy, abnormality of function of blood coagulation and the marker for predicting prognosis. Severe abnormality of function of blood coagulation is an important marker with high sensitivity and specificity in ASH or SSH patients without hepatic encephalopathy.