Microbial communities in contaminated sediments, associated with bioremediation of uranium to submicromolar levels

Microbial enumeration, 16S rRNA gene clone libraries, and chemical analysis were used to evaluate the in situ biological reduction and immobilization of uranium(VI) in a long-term experiment (more than 2 years) conducted at a highly uranium-contaminated site (up to 60 mg/liter and 800 mg/kg solids) of the U.S. Department of Energy in Oak Ridge, TN. Bioreduction was achieved by conditioning groundwater above ground and then stimulating growth of denitrifying, Fe(III)-reducing, and sulfate-reducing bacteria in situ through weekly injection of ethanol into the subsurface. After nearly 2 years of intermittent injection of ethanol, aqueous U levels fell below the U.S. Environmental Protection Agency maximum contaminant level for drinking water and groundwater (<30 microg/liter or 0.126 microM). Sediment microbial communities from the treatment zone were compared with those from a control well without biostimulation. Most-probable-number estimations indicated that microorganisms implicated in bioremediation accumulated in the sediments of the treatment zone but were either absent or in very low numbers in an untreated control area. Organisms belonging to genera known to include U(VI) reducers were detected, including Desulfovibrio, Geobacter, Anaeromyxobacter, Desulfosporosinus, and Acidovorax spp. The predominant sulfate-reducing bacterial species were Desulfovibrio spp., while the iron reducers were represented by Ferribacterium spp. and Geothrix spp. Diversity-based clustering revealed differences between treated and untreated zones and also within samples of the treated area. Spatial differences in community structure within the treatment zone were likely related to the hydraulic pathway and to electron donor metabolism during biostimulation.     

The cultural politics of the supernatural in Theravada Buddhist Thailand

This article does not have an abstract     

B cell depletion in HIV-1 subtype A infected Ugandan adults: relationship to CD4 T cell count, viral load and humoral immune responses

To better understand the nature of B cell dysfunctions in subjects infected with HIV-1 subtype A, a rural cohort of 50 treatment-naïve Ugandan patients chronically infected with HIV-1 subtype A was studied, and the relationship between B cell depletion and HIV disease was assessed. B cell absolute counts were found to be significantly lower in HIV-1+ patients, when compared to community matched negative controls (p<0.0001). HIV-1-infected patients displayed variable functional and binding antibody titers that showed no correlation with viral load or CD4+ T cell count. However, B cell absolute counts were found to correlate inversely with neutralizing antibody (NAb) titers against subtype A (p = 0.05) and subtype CRF02_AG (p = 0.02) viruses. A positive correlation was observed between subtype A gp120 binding antibody titers and NAb breadth (p = 0.02) and mean titer against the 10 viruses (p = 0.0002). In addition, HIV-1 subtype A sera showed preferential neutralization of the 5 subtype A or CRF02_AG pseudoviruses, as compared with 5 pseudoviruses from subtypes B, C or D (p<0.001). These data demonstrate that in patients with chronic HIV-1 subtype A infection, significant B cell depletion can be observed, the degree of which does not appear to be associated with a decrease in functional antibodies. These findings also highlight the potential importance of subtype in the specificity of cross-clade neutralization in HIV-1 infection.     

The impact of industrial biotechnology

In this review, the impact of industrial (or "white") biotechnology can have on our society and economy is discussed. An overview is given of industrial biotechnology and its applications in a number of product categories ranging from food ingredients, vitamins, bio-colorants, solvents, plastics and biofuels. The use of fossil resources is compared with renewable resources as the preferred feedstock for industrial biotechnology. A brief discussion is also given of the expected changes in society and technology, ranging from the shift in the supply of resources, the growing need for efficiency and sustainability of the production systems, changing consumer perception and behaviour and changing agricultural systems and practices. Many of these changes are expected to speed up the transition from a fossil-based to a bio-based economy and society.     

Oxidative stress mediates neuronal DNA damage and apoptosis in response to cytosine arabinoside

Cytosine arabinoside (AraC) is a nucleoside analog that produces significant neurotoxicity in cancer patients. The mechanism by which AraC causes neuronal death is a matter of some debate because the conventional understanding of AraC toxicity requires incorporation into newly synthesized DNA. Here we demonstrate that AraC-induced apoptosis of cultured cerebral cortical neurons is mediated by oxidative stress. AraC-induced cell death was reduced by treatment with several different free-radical scavengers (N-acetyl-L-cysteine, dipyridamole, uric acid, and vitamin E) and was increased following depletion of cellular glutathione stores. AraC induced the formation of reactive oxygen species in neurons as measured by an increase in the fluorescence of the dye 5-(6)-carboxy-2',7'-dichlorodihydrofluorescein diacetate. AraC produced DNA single-strand breaks as measured by single-cell gel electrophoresis and the level of DNA strand breakage was reduced by treatment with the free radical scavengers. These data support a model in which AraC induces neuronal apoptosis by provoking the generation of reactive oxygen species, causing oxidative DNA damage and initiating the p53-dependent apoptotic program. These observations suggest the use of antioxidant therapies to reduce neurotoxicity in AraC chemotherapeutic regimens.     

Studies on PVP hydrogel-supported luminol chemiluminescence: 2. Luminometer calibration and potential analytical applications.

The use of poly(N-vinyl-2-pyrrolidone) (PVP) hydrogel-supported luminol chemiluminescence (CL) for the automatic determination of hydrogen peroxide and the quantification of the antiradical capacity of Trolox is described. The hydrogel containing luminol and hemin is prepared directly on a 96-well microplate and can be stored for up to 3 months without significant decrease in CL quantum yields. Furthermore, this system can also be used as a secondary light standard for the calibration of microplate luminometers.     

Intermediate mutation frequencies favor evolution of multidrug resistance in Escherichia coli

In studying the interplay between mutation frequencies and antibiotic resistance among Escherichia coli natural isolates, we observed that modest modifications of mutation frequency may significantly influence the evolution of antibiotic resistance. The strains having intermediate mutation frequencies have significantly more antibiotic resistances than strains having low and high mutation frequencies.     

7-(aryl/heteroaryl-2-ylethynyl)-4-phenylamino-3-quinolinecarbonitriles as new Src kinase inhibitors: addition of water solubilizing groups

New 4-phenylamino-3-quinolinecarbonitriles with a 7-ethynyl group substituted by a pyridine, phenyl or thiophene ring containing basic water solubilizing groups were prepared and evaluated as Src kinase inhibitors. Of these new analogs, potent activity was observed with compounds having a (2,4-dichloro-5-methoxyphenyl)amino group at C-4, a methoxy or ethoxy group at C-6, and a pyridyl group bearing a dimethylamine or N-methylpiperazine on the ethynyl group at C-7.     

Microbial production and application of sophorolipids

Sophorolipids are surface-active compounds synthesized by a selected number of yeast species. They have been known for over 40 years, but because of growing environmental awareness, they recently regained attention as biosurfactants due to their biodegradability, low ecotoxicity, and production based on renewable resources. In this paper, an overview is given of the producing yeast strains and various aspects of fermentative sophorolipid production. Also, the biochemical pathways and regulatory mechanisms involved in sophorolipid biosynthesis are outlined. To conclude, a summary is given on possible applications of sophorolipids, either as native or modified molecules.