Enhancing the intrinsic bioremediation of PAH-contaminated anoxic estuarine sediments with biostimulating agents.
(73/492)
Estuarine sediments are frequently polluted with hydrocarbons from fuel spills and industrial wastes. Polycyclic aromatic hydrocarbons (PAHs) are components of these contaminants that tend to accumulate in the sediment due to their low aqueous solubility, low volatility, and high affinity for particulate matter. The toxic, recalcitrant, mutagenic, and carcinogenic nature of these compounds may require aggressive treatment to remediate polluted sites effectively. In petroleum-contaminated sediments near a petrochemical industry in Gwangyang Bay, Korea, in situ PAH concentrations ranged from 10 to 2,900 microg/kg dry sediment. To enhance the biodegradation rate of PAHs under anaerobic conditions, sediment samples were amended with biostimulating agents alone or in combination: nitrogen and phosphorus in the form of slow-release fertilizer (SRF), lactate, yeast extract (YE), and Tween 80. When added to the sediment individually, all tested agents enhanced the degradation of PAHs, including naphthalene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, and benzo[a]pyrene. Moreover, the combination of SRF, Tween 80, and lactate increased the PAH degradation rate 1.2-8.2 times above that of untreated sediment (0.01-10 microg PAH/kg dry sediment/day). Our results indicated that in situ contaminant PAHs in anoxic sediment, including high molecular weight PAHs, were degraded biologically and that the addition of stimulators increased the biodegradation potential of the intrinsic microbial populations. Our results will contribute to the development of new strategies for in situ treatment of PAH-contaminated anoxic sediments. (+info)
Effect of Australian tea tree oil on Gyrodactylus spp. infection of the three-spined stickleback Gasterosteus aculeatus.
(74/492)
Gyrodactylus spp. infections of commercially farmed fishes are responsible for significant economic losses. Existing treatments have proved uneconomic, stressful to the fishes, and ecologically damaging. Essential oils are naturally occurring compounds that exhibit a wide range of anti-microbial and anti-fungal activities. This study explored the possibility of using Australian tea tree (Melaleuca alternifolia) oil (TTO) to treat Gyrodactylus spp. infection on the three-spined stickleback Gasterosteus aculeatus. In the presence of 0.01 % Tween 80 as an emulsifier, TTO treatments at concentrations between 3 and 30 ppmv (parts per million by volume) lowered the prevalence and significantly reduced the parasite burden of sticklebacks naturally infected with Gyrodactylus spp. In addition, Tween 80 alone exhibited parasiticidal activity against Gyrodactylus spp. These findings show the potential of TTO in combination with Tween 80 as an effective treatment of Gyrodactylus spp. infection of fishes. (+info)
Up-regulation of insulin-like growth factor binding protein-3 by apigenin leads to growth inhibition and apoptosis of 22Rv1 xenograft in athymic nude mice.
(75/492)
Epidemiological studies suggest that increased intake of fruits and vegetables may be associated with a reduced risk of prostate cancer. Apigenin (4', 5, 7,-trihydroxyflavone), a common dietary flavonoid abundantly present in fruits and vegetables, has shown remarkable anti-proliferative effects against various malignant cell lines. However, the mechanisms underlying these effects remain to be elucidated. We investigated the in vivo growth inhibitory effects of apigenin on androgen-sensitive human prostate carcinoma 22Rv1 tumor xenograft subcutaneously implanted in athymic male nude mice. Apigenin was administered to mice by gavage at doses of 20 and 50 mug/mouse/day in 0.2 ml of a vehicle containing 0.5% methyl cellulose and 0.025% Tween 20 in two different protocols. In the first protocol, apigenin was administered for 2 wk before inoculation of tumor and was continued for 8 wk, resulting in significant inhibition of tumor volume by 44 and 59% (P<0.002 and 0.0001), and wet weight of tumor by 41 and 53% (P<0.05), respectively. In the second protocol, administration of apigenin began 2 wk after tumor inoculation and continued for 8 wk; tumor volume and wet weights of tumor were reduced by 39 and 53% (P<0.01 and 0.002) and 31 and 42% (P<0.05), respectively. The tumor inhibitory effect of apigenin was more pronounced in the first protocol of extended treatment, which was associated with increased accumulation of human IGFBP-3 in mouse serum along with significant increase in IGFBP-3 mRNA and protein expression in tumor xenograft. Apigenin intake by these mice also resulted in simultaneous decrease in serum IGF-I levels and induction of apoptosis in tumor xenograft. Importantly, tumor growth inhibition, induction of apoptosis, and accumulation of IGFBP-3 correlated with increasing serum and tumor apigenin levels. In both studies, animals did not exhibit any signs of toxicity or reduced food consumption. In cell culture studies, apigenin treatment resulted in cell growth inhibition and induction of apoptosis, which correlated with increased accumulation of IGFBP-3 in culture medium and cell lysate. These effects were associated with significant reduction in IGF-I secretion; inhibition of IGF-I-induced cell cycle progression and insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation, along with an increase in sub-G1 peak by apigenin. Further, treatment of cells with IGFBP-3 antisense oligonucleotide reversed these effects and attenuated apigenin-mediated inhibition of IRS-1 phosphorylation conferring inhibitory effects of apigenin on IGF-signaling. This study presents the first evidence that the in vitro and in vivo growth inhibitory effects of apigenin involve modulation of IGF-axis signaling in prostate cancer. (+info)
A novel type of detergent-resistant membranes may contribute to an early protein sorting event in epithelial cells.
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One sorting mechanism of apical and basolateral proteins in epithelial cells is based on their solubility profiles with Triton X-100. Nevertheless, apical proteins themselves are also segregated beyond the trans-Golgi network by virtue of their association or nonassociation with cholesterol/sphingolipid-rich microdomains (Jacob, R., and Naim, H. Y. (2001) Curr. Biol. 11, 1444-1450). Therefore, extractability with Triton X-100 does not constitute an absolute criterion of protein sorting. Here, we investigate the solubility patterns of apical and basolateral proteins with other detergents and demonstrate that the mild detergent Tween 20 is adequate to discriminate between apical and basolateral proteins during early stages in their biosynthesis. Although the mannose-rich forms of the apical proteins sucrase-isomaltase, lactase-phlorizin hydrolase, aminopeptidase N, and dipeptidylpeptidase IV reveal similar solubility profiles comprising soluble and nonsoluble fractions, the basolateral proteins, vesicular stomatitis virus G protein, major histocompatibility complex class I, and CD46 are entirely soluble with this detergent. The insoluble Tween 20 membranes are enriched in phosphatidylinositol and phosphatidylglycerol compatible with their synthesis in the endoplasmic reticulum and the existence of a novel class of detergent-resistant membranes. The association of the mannose-rich biosynthetic forms of the apical proteins, sucraseisomaltase, lactase-phlorizin hydrolase, aminopeptidase N, and dipeptidylpeptidase IV with the Tween 20-resistant membranes suggests an early polarized sorting mechanism prior to maturation in the Golgi apparatus. (+info)
Development of a rapid method for simultaneous recovery of diverse microbes in drinking water by ultrafiltration with sodium polyphosphate and surfactants.
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The ability to simultaneously concentrate diverse microbes is an important consideration for sample collection methods that are used for emergency response and environmental monitoring when drinking water may be contaminated with an array of unknown microbes. This study focused on developing a concentration method using ultrafilters and different combinations of a chemical dispersant (sodium polyphosphate [NaPP]) and surfactants. Tap water samples were seeded with bacteriophage MS2, Escherichia coli, Enterococcus faecalis, Cryptosporidium parvum, 4.5-microm microspheres, Salmonella enterica serovar Typhimurium, Bacillus globigii endospores, and echovirus 1. Ten-liter tap water samples were concentrated to approximately 250 ml in 12 to 42 min, depending on the experimental condition. Initial experiments indicated that pretreating filters with fetal bovine serum or NaPP resulted in an increase in microbe recovery. The addition of NaPP to the tap water samples resulted in significantly higher microbe and microsphere recovery efficiencies. Backflushing of the ultrafilter was found to significantly improve recovery efficiencies. The effectiveness of backflushing was improved further with the addition of Tween 80 to the backflush solution. The ultrafiltration method developed in this study, incorporating the use of NaPP pretreatment and surfactant solution backflushing, was found to recover MS2, C. parvum, microspheres, and several bacterial species with mean recovery efficiencies of 70 to 93%. The mean recovery efficiency for echovirus 1 (49%) was the lowest of the microbes studied for this method. This research demonstrates that ultrafiltration can be effective for recovering diverse microbes simultaneously in tap water and that chemical dispersants and surfactants can be beneficial for improving microbial recovery using this technique. (+info)
Microbial risk indicators of early childhood caries.
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The aim of this study was to use molecular identification methods, such as 16S RNA gene sequence and reverse-capture checkerboard hybridization, for identification of the bacteria associated with dental caries and with dental health in a subset of 204 twins aged 1.5 to 7 years old. A total of 448 plaque samples (118 collected from caries-free subjects and 330 from caries-active subjects) were used for analysis. We compared the bacteria found in biofilms of children exhibiting severe dental caries, with different degrees of lesion severity, with those found in biofilms of caries-free children. A panel of 82 bacterial species was selected, and a PCR-based reverse-capture checkerboard method was used for detection. A simple univariate test was used to determine the overabundance and underabundance of bacterial species in the diseased and in the healthy groups. Features identified with this univariate test were used to construct a probabilistic disease prediction model. Furthermore, a method for the analysis of global patterns of gene expression was performed to permit simultaneous analysis of the abundance of significant species by allowing cross-bacterial comparisons of abundance profiles between caries-active and caries-free subjects. Our results suggested that global patterns of microbial abundance in this population are very distinctive. The top bacterial species found to be overabundant in the caries-active group were Actinomyces sp. strain B19SC, Streptococcus mutans, and Lactobacillus spp., which exhibited an inverse relationship to beneficial bacterial species, such as Streptococcus parasanguinis, Abiotrophia defectiva, Streptococcus mitis, Streptococcus oralis, and Streptococcus sanguinis. (+info)
Reduction of infectivity of schistosome cercariae by application of cercaricidal oil to water.
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Schistosomiasis continues to plague populations living in disease-endemic areas, and exposure to infective cercariae results in more than 200 million cases worldwide. Laboratory experiments were conducted to test whether a cercaricidal film applied directly to the water surface can reduce viability of cercariae. A distillate from inexpensive cedarwood oil enriched for cedrol in a mixed oil fraction was formulated (1:5) with the surfactant Tween 80. When applied to the surface of clean and turbid water in test vessels, the formulation spread across and just below the air-water interface, causing inactivation of Schistosoma mansoni cercariae within minutes. The active ingredient was heat stable and reduced schistosome survival and infectivity by 90% and 99.2%, respectively in a mouse model. The effective dose (13 mug/cm(2)) was dependent on surface area rather than volume of water treated. We conclude that application of the biodegradable formulation to the surface of schistosome-infested waters may be an effective, economical, and safe means of reducing human infections. (+info)
Effect of the synthesized mycolic acid on the biodegradation of diesel oil by Gordonia nitida strain LE31.
(80/492)
The dynamics of diesel oil biodegradation were previously investigated at initial substrate concentrations of 1000 to 20,000 ppm using Gordonia nitida isolated from wastewater. Following the gas chromatogram profiles of diesel oil degradation, diesel oil with concentrations of up to 15,000 ppm was efficiently degraded by this strain. At a concentrations of 20,000 ppm, however, the degradation by this strain was not effective. The enhancement of the biodegradation of diesel oi1 (at 15,000 and 20,000 ppm) by a synthetic mycolic acid biosurfactant (at 9, 90 and 900 ppm) was also investigated. In G. nitida inoculated cultures, the degradation of diesel oil was enhanced by the biosurfactant. For comparison, diesel oil degradation in batch incubations was measured after the addition of rhamnolipid and other surfactants. Synthetic mycolic acid enhanced the degradation to a greater extent than any other surfactant tested. Additionally, it was demonstrated that the degradation-enhancing property of synthetic mycolic acid was similar to that of rhamnolipid and Tween 80. (+info)