Induction of Detoxification Enzymes by Feeding Unblanched Brussels Sprouts Containing Active Myrosinase to Mice for 2 Wk

Abstract: In cruciferous vegetables, myrosinase metabolizes the relatively inactive glucosinolates into isothiocyanates and other products that have the ability to increase detoxification enzyme expression. Thus, maintaining myrosinase activity during food preparation may be critical to receiving the maximum benefit of consumption of Brussels sprouts or other cruciferous vegetables. To test the importance of maintaining myrosinase activity for maximizing bioactivity, experimental diets containing 20% unblanched (active myrosinase) or 20% blanched (inactivated myrosinase) freeze-dried Brussels sprouts and a nutrient-matched control diet were evaluated in vitro and in vivo for their ability to induce detoxification enzymes. Treatment of immortalized HepG2 human hepatoma cells with the unblanched Brussels sprout diet caused a greater increase quinone activity compared to the blanched Brussels sprout diet. C3H/HeJ mice fed the unblanched Brussels sprout diets for 2 wk had significantly higher plasma sulforaphane concentrations. Liver expression of CYP1A1 and epoxide hydrolase, measured using real-time PCR, was correlated with the plasma concentration of sulforaphane. In the lung, expression of epoxide hydrolase, thioredoxin reductase, UDP glucuronosyltransferase, quinone reductase, heme oxygenase, CYP1A1, CYP1A2, and CYP1B1 were also correlated with the plasma concentration of sulforaphane. Together these data demonstrate that, as predicted by the in vitro experiment, in vivo exposure to Brussels sprouts with active myrosinase resulted in greater induction of both phase I and phase II detoxification enzymes in the liver and the lungs that correlated with plasma sulforaphane concentrations.     

Biodegradation of RDX and MNX with Rhodococcus sp. strain DN22: new insights into the degradation pathway

Previously we demonstrated that Rhodococcus sp. strain DN22 can degrade RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) aerobically via initial denitration. The present study describes the role of oxygen and water in the key denitration step leading to RDX decomposition using (18)O(2) and H(2)(18)O labeling experiments. We also investigated degradation of MNX (hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine) with DN22 under similar conditions. DN22 degraded RDX and MNX giving NO(2)(-), NO(3)(-), NDAB (4-nitro-diazabutanal), NH(3), N(2)O, and HCHO with NO(2)(-)/NO(3)(-) molar ratio reaching 17 and ca. 2, respectively. In the presence of (18)O(2), DN22 degraded RDX and produced NO(2)(-) with m/z at 46 Da that subsequently oxidized to NO(3)(-) containing one (18)O atom, but in the presence of H(2)(18)O we detected NO(3)(-) without (18)O. A control containing NO(2)(-), DN22, and (18)O(2) gave NO(3)(-) with one (18)O, confirming biotic oxidation of NO(2)(-) to NO(3)(-). Treatment of MNX with DN22 and (18)O(2) produced NO(3)(-) with two mass ions, one (66 Da) incorporating two (18)O atoms and another (64 Da) incorporating only one (18)O atom and we attributed their formation to bio-oxidation of the initially formed NO and NO(2)(-), respectively. In the presence of H(2)(18)O we detected NO(2)(-) with two different masses, one representing NO(2)(-) (46 Da) and another representing NO(2)(-) (48 Da) with the inclusion of one (18)O atom suggesting auto-oxidation of NO to NO(2)(-). Results indicated that denitration of either RDX or MNX and denitrosation of MNX by DN22 did not involve direct participation of either oxygen or water, but both played major roles in subsequent secondary chemical and biochemical reactions of NO and NO(2)(-).     

Occurrence, synthesis, and mammalian cell cytotoxicity and genotoxicity of haloacetamides: an emerging class of nitrogenous drinking water disinfection byproducts

The haloacetamides, a class of emerging nitrogenous drinking water disinfection byproduct (DBPs), were analyzed for their chronic cytotoxicity and for the induction of genomic DNA damage in Chinese hamster ovary cells. The rank order for cytotoxicity of 13 haloacetamides was DIAcAm > IAcAm > BAcAm > TBAcAm > BIAcAm > DBCAcAm > CIAcAm > BDCAcAm > DBAcAm > BCAcAm > CAcAm > DCAcAm > TCAcAm. The rank order of their genotoxicity was TBAcAm > DIAcAm approximately equal to IAcAm > BAcAm > DBCAcAm > BIAcAm > BDCAcAm > CIAcAm > BCAcAm > DBAcAm > CAcAm > TCAcAm. DCAcAm was not genotoxic. Cytotoxicity and genotoxicity were primarily determined by the leaving tendency of the halogens and followed the order I > Br > > Cl. With the exception of brominated trihaloacetamides, most of the toxicity rank order was consistent with structure-activity relationship expectations. For di- and trihaloacetamides, the presence of at least one good leaving halogen group (I or Br but not Cl) appears to be critical for significant toxic activity. Log P was not a factor for monohaloacetamides but may play a role in the genotoxicity of trihaloacetamides and possible activation of dihaloacetamides by intracellular GSH and -SH compounds.     

Electricity generation by Rhodopseudomonas palustris DX-1

Bacteria able to generate electricity in microbial fuel cells (MFCs) are of great interest, but there are few strains capable of high power production in these systems. Here we report that the phototrophic purple nonsulfur bacterium Rhodopseudomonas palustris DX-1, isolated from an MFC, produced electricity at higher power densities (2720 +/- 60 mW/m2) than mixed cultures in the same device. While Rhodopseudomonas species are known for their ability to generate hydrogen, they have not previously been shown to generate power in an MFC, and current was generated without the need for light or hydrogen production. Strain DX-1 utilizes a wide variety of substrates (volatile acids, yeast extract, and thiosulfate) for power production in different metabolic modes, making it highly useful for studying power generation in MFCs and generating power from a range of simple and complex sources of organic matter. These results demonstrate that a phototrophic purple nonsulfur bacterium can efficiently generate electricity by direct electron transfer in MFCs, providing another model microorganism for MFC investigations.     

Gene expression profiles for detecting and distinguishing potential endocrine-disrupting compounds in environmental samples

Industrial and municipal processes may produce and release endocrine-disrupting compounds (EDCs) into the environment, but the exact nature of their effects is difficult to investigate. EDCs typically exert their effect by affecting gene expression aberrantly. To determine if gene expression profiles could be used to detect and distinguish estrogenic EDCs, an estrogen receptor positive human breast cancer cell line (MCF-7) was exposed to known estrogenic compounds, suspected EDCs, and extracts from three effluent samples. A set of specifically estrogen-regulated genes was identified by microarray analysis. Nine estrogen up-regulated genes (IGFBP4, HSPA8, B4GALT1, XBP1, KRT8, GTPBP4, HNRPAB, SLC2A1, and CALM1) and two estrogen down-regulated genes (ID2 and ZNF217) were consistently detectable in response to estrogen and other estrogenic compounds. Gene expression patterns in cells that were exposed to effluent sample extracts were compared to gene expression patterns in cells that were exposed to known endocrines. Using this technique, two of the effluent samples were shown to have estrogenic activity. This approach could easily be extended to screen for other types of receptor-mediated endocrine disruption. For example, cells expressing androgen or aryl hydrocarbon receptors could be used in gene expression profiling assays to detect androgenic effects or for the presence of bioactive aromatic hydrocarbons. Gene expression profiling is emerging as a sensitive and specific method to screen complex samples for endocrine disrupting activity.     

Continuous electricity generation from domestic wastewater and organic substrates in a flat plate microbial fuel cell

A microbial fuel cell (MFC) is a device that converts organic matter to electricity using microorganisms as the biocatalyst. Most MFCs contain two electrodes separated into one or two chambers that are operated as a completely mixed reactor. In this study, a flat plate MFC (FPMFC) was designed to operate as a plug flow reactor (no mixing) using a combined electrode/proton exchange membrane (PEM) system. The reactor consisted of a single channel formed between two nonconductive plates that were separated into two halves by the electrode/PEM assembly. Each electrode was placed on an opposite side of the PEM, with the anode facing the chamber containing the liquid phase and the cathode facing a chamber containing only air. Electricity generation using the FPMFC was examined by continuously feeding a solution containing wastewater, or a specific substrate, into the anode chamber. The system was initially acclimated for 1 month using domestic wastewater orwastewater enriched with a specific substrate such as acetate. Average power density using only domestic wastewater was 72+/-1 mW/m2 at a liquid flow rate of 0.39 mL/min [42% COD (chemical oxygen demand) removal, 1.1 h HRT (hydraulic retention time)]. At a longer HRT = 4.0 h, there was 79% COD removal and an average power density of 43+/-1 mW/m2. Power output was found to be a function of wastewater strength according to a Monod-type relationship, with a half-saturation constant of Ks = 461 or 719 mg COD/L. Power generation was sustained at high rates with several organic substrates (all at approximately 1000 mg COD/L), including glucose (212+/-2 mW/ m2), acetate (286+/-3 mW/m2), butyrate (220+/-1 mW/ m2), dextran (150+/-1 mW/m2), and starch (242+/-3 mW/ m2). These results demonstrate the versatility of power generation in a MFC with a variety of organic substrates and show that power can be generated at a high rate in a continuous flow reactor system.     

Transdermal nicotine use in postmenopausal women: does the treatment efficacy differ in women using and not using hormone replacement therapy?

This study of postmenopausal female smokers (N = 94) asked: During short-term smoking abstinence, do the beneficial effects of transdermal nicotine replacement therapy (NRT) on acute symptomatology (i.e., withdrawal, cigarette craving, smoking urges, mood, depressive symptoms, motor speed, and reaction time) differ in women who use and do not use hormone replacement therapy (HRT)? Participants were recruited according to HRT and non-HRT use (self-selecting), then randomized within strata to active nicotine or placebo nicotine patch. After 1 baseline week of smoking, participants quit smoking for 2 weeks. Women received cessation counseling and were monitored for abstinence. Dependent measures were collected during five clinic visits. Two-way analysis of covariance (ANCOVA) were run on change scores for dependent variables, with nicotine patch group (active/placebo) and HRT group (HRT/non-HRT) as independent variables and age as a covariate. No interactions were found between HRT and patch condition, but both showed specific effects. During the first abstinent week, women on active nicotine patch (compared with placebo) experienced less severe withdrawal, greater reductions in cigarette cravings, and lower (more favorable) Factor 1 scores on the Questionnaire of Smoking Urges. During the second abstinent week, women using HRT (compared with the non-HRT group) exhibited better mood (Profile of Mood States scores) and less depression (Beck Depression Inventory scores). These results suggest the following: First, the efficacy of transdermal nicotine replacement is not adversely modified by women's HRT use; second, ovarian hormones might influence women's responses to smoking cessation, and thus should be considered in developing effective strategies for women to quit smoking.     

Effect of level of oil inclusion in the diet of dairy cows at pasture on animal performance and milk composition and properties

The effect of including additional oil, incorporated as whole rapeseeds, in the diet of 64 Holstein–Friesian dairy cows (32 mid‐ and 32 late‐lactation) at pasture on animal performance and milk fat composition and properties was followed over a continuous trial of 20 weeks duration. Within two stages of lactation (mid, 130 ± 16.2 days, or late, 231 ± 58.9 days), cows were allocated to concentrate treatments representing four levels of rapeseed oil inclusion, 0 (control), 200, 400 and 600 g oil day^?1. Oil inclusion had little effect on milk yield but decreased milk fat content significantly (P < 0.01), with a mean depression of 0.40% at the highest level of oil inclusion. The content of milk protein also decreased with increasing addition of oil, but the decrease was smaller than the milk fat depression and was not statistically significant. Increasing the level of rapeseed oil in the diet to 600 g oil day^?1 resulted in linear changes in milk fat and protein concentrations which were described by regression equations. For each 100 g of rapeseed oil added to the diet, milk fat content decreased by 0.068% in mid‐lactation cows and 0.061% in late‐lactation cows, while protein content decreased by 0.026% in mid‐lactation cows and 0.028% in late‐lactation cows. Total unsaturated fatty acid content of milk fat also increased in a linear fashion with increased level of oil addition, from 345.7 g kg^?1 total fatty acids in control milk fat to 459.3 g kg^?1 total fatty acids at 600 g oil day^?1, while total saturated fatty acids decreased in the same milk fats from 640.7 to 522.2 g kg^?1 total fatty acids. These changes were reflected in lower solid fat contents (SFC) in the milk fat at the lower temperatures of measurement, eg 41% SFC at 5 °C at the highest level of oil inclusion compared with 52% in the control milk fat. However, SFC at 20 °C showed little difference with increasing level of dietary oil addition, an important factor in maintaining product integrity at room temperatures. The relatively high content of the monounsaturated fatty acid C18:1 (345.5 g kg^?1 total fatty acids at 600 g oil day^?1) and low content of polyunsaturated fatty acids (total C18:2 and C18:3 <40 g kg^?1 total fatty acids at 600 g oil day^?1) ensured that the oxidative stability of the treatment and control milk fats did not differ significantly. Stage of lactation had an unexplained effect of consistent magnitude on milk fat composition throughout the trial period, with late‐lactation animals producing milk fats containing a significantly (P < 0.001) higher proportion of unsaturated fatty acids than the mid‐lactation animals. Changes in the proportions of unsaturated fatty acids in milk fat, as reflected by changes in iodine value, were established within 2 weeks of the trial commencing and persisted over the 20 weeks of the trial duration. No adverse effect on animal health from this type of dietary manipulation was identified. Copyright © 2004 Society of Chemical Industry     

Free radical chemistry of disinfection byproducts. 2. Rate constants and degradation mechanisms of trichloronitromethane (chloropicrin)

Absolute rate constants for the free-radical-induced degradation of trichloronitromethane (TCNM, chloropicrin) were determined using electron pulse radiolysis and transient absorption spectroscopy. Rate constants for hydroxyl radical, *OH, and hydrated electron, e(aq)-, reactions were (4.97 +/- 0.28) x 10(7) M(-1) s(-1) and (2.13 +/- 0.03) x 10(10) M(-1) s(-1), respectively. It appears that the *OH adds to the nitro-group, while the e(aq)- reacts via dissociative electron attachment to give two carbon centered radicals. The mechanisms of these free radical reactions with TCNM were investigated, using 60Co gamma irradiation at various absorbed doses, measuring the disappearance of TCNM and the appearance of the product nitrate and chloride ions. The rate constants and mechanistic data were combined in a kinetic computer model that was used to describe the major free radical pathways for the destruction of TCNM in solution. These data are applicable to other advanced oxidation/reduction processes.     

Tubular membrane cathodes for scalable power generation in microbial fuel cells

One of the greatest challenges for using microbial fuel cells (MFCs) for wastewater treatment is creating a scalable architecture that provides large surface areas for oxygen reduction at the cathode and bacteria growth on the anode. We demonstrate here a scalable cathode concept by showing that a tubular ultrafiltration membrane with a conductive graphite coating and a nonprecious metal catalyst (CoTMPP) can be used to produce power in an MFC. Using a carbon paper anode (surface area Aan = 7 cm2, surface area per reactor volume Aan,s = 25 m2/m3), an MFC with two 3-cm tube cathodes (Acat = 27 cm2, Acat,s = 84 m2/m3) generated up to 8.8 W/m3 (403 mW/m2) using glucose [0.8 g/L in a 50 mM phosphate buffer solution (PBS)], which was only slightly less than that produced using a carbon paper cathode with a Pt catalyst (9.9 W/m3, 394 mW/m2; Acat= 7 cm2, Acat,s= 25 m2/m3). Coulombic efficiencies (CEs) with carbon paper anodes were 25-40% with tube cathodes (CoTMPP), compared to 7-19% with a carbon paper cathode. When a high-surface-area graphite brush anode was used (Aan = 2235 cm2, Aan,s = 7700 m2/m3) with two tube cathodes placed inside the reactor (Acat = 27 cm2, Acas, = 93 m2/m3), the MFC produced 17.7 W/m3 with a CE = 70-74% (200 mM PBS). Further increases in the surface area of the tube cathodes to 54 cm2 (120 m2/m3) increased the total power output (from 0.51 to 0.83 mW), but the increase in volume resulted in a constant volumetric power density (approximately 18 W/m3). These results demonstrate that an MFC design using tubular cathodes coated with nonprecious metal catalysts, and brush anodes, is a promising architecture that is intrinsically scalable for creating larger systems. Further increases in power output will be possible through the development of cathodes with lower internal resistances.