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941.
B. T. Ashok S. Saxena K. P. Singh J. Musarrat 《World journal of microbiology & biotechnology》1995,11(6):691-692
Six polycyclic aromatic hydrocarbons [naphthalene, anthracene, phenanthrene, pyrene, chrysene and benzo(a)-pyrene] were detected in soil receiving effluents from an oil refinery. Biodegradation studies revealed a time-dependent disappearance of these polycyclic aromatic hydrocarbons when they were added to soil samples: naphthalene disappeared completely in 60 days, whereas phenanthrene, anthracene, pyrene, chrysene and benzo(a)pyrene decreased by 87%, 34%, 21%, 5% and 40%, respectively, in 120 days.B.T. Ashok and J. Musarrat were and S. Saxena is with the Interdisciplinary Biotechnology Unit, A.M.U., Aligarh-202002, Uttar Pradesh, India. K.P. Singh is with the Environmental Chemistry Section, Industrial Toxicology Research Centre, M.G. Road, Lucknow-226001, Uttar Pradesh, India. B.T. Ashok is now with the Department of Biochemistry, J.N. Medical College, A.M.U., Aligarh-202002, Uttar Pradesh, India. J. Musarrat is now with the Department of Radiology and Blochemistry Program. The Ohio State University, Columbus, OH 43210, USA. 相似文献
942.
The volatile acids of sun-cured Greek tobacco have been studied. Examination of this material by GC-MS supplemented by other spectroscopic methods and in some instances by synthesis, has permitted the identification of nearly a hundred compounds. About half of them have not been encountered previously in tobacco or tobacco smoke, and the majority of the new compounds are straight and branched-chain unsaturated acids and aromatic acids. Five of the oxygenated acids are evidently seco- or nor-terpenoids. 相似文献
943.
Myong Won Kahng Wing Liu Hayato Sanefuji James H. Resau Barry M. Heatfield Benjamin F. Trump 《Chemico-biological interactions》1981,36(2):249-256
Aryl hydrocarbon hydroxylase (AHH) was present in explant cultures of human prostate obtained from surgery of benign prostatic hyperplasia and was inducible by benz[a]anthracene (BA). The induction of AHH ranged from 14- to 150-fold when compared with control values and 10-fold variation of AHH inducibility among individuals was observed. Epithelial cells grown from human prostate tissue also contained measurable AHH activity and AHH was inducible by BA and 7,12-dimethylbenz[a]anthracene (DMBA). Inducibility of AHH by BA ranged from 2- to 63-fold. The inducibility of AHH by DMBA was always less than that by BA. In cells treated with N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), there were no changes in AHH activity. These findings support the view that the human prostate is susceptible to environmental polycyclic hydrocarbon carcinogens and that environmental and occupational factors might contribute to the etiology of human prostatic carcinoma. 相似文献
944.
Benzo[a]pyrene is metabolised by isolated viable hepatocytes from both untreated and 3-methylcholanthrene pretreated rats to reactive metabolites which covalently bind to DNA. The DNA from the hepatocytes was isolated, purified and enzymically hydrolysed to deoxyribonucleosides. The hydrocarbon-deoxyribonucleoside products after initial separation, on small columns of Sephadex LH-20, from unhydrolysed DNA, oligonucleotides and free bases, were resolved by high pressure liquid chromatography (HPLC). The qualitative nature of the adducts found in both control and pretreated cells was virtually identical; however pretreatment with 3-methylcholanthrene resulted in a quantitatively higher level of binding. The major hydrocarbon-deoxyribonucleoside adduct, found in hepatocytes co-chromatographed with that obtained following reaction of the diol-epoxide, (±)7α,8β-dihydroxy-9β,10β-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene with DNA. Small amounts of other adducts were also present including a more polar product which co-chromatographed with the major hydrocarbon-deoxyribonucleoside adduct formed following microsomal activation of 9-hydroxybenzo[a]pyrene and subsequent binding to DNA. In contrast to the results with hepatocytes, when microsomes were used to metabolically activate benzo[a]pyrene, the major DNA bound-product co-chromatographed with the more polar adduct formed upon further metabolism of 9-hydroxybenzo[a]pyrene. These results illustrate that great caution must be exercised in the extrapolation of results obtained from short-term mutagenesis test systems, utilising microsomes, to in vivo carcinogenicity studies. 相似文献
945.
A model peptide, FKCRRWQWRMKKLGA, residues 17-31 of bovine lactoferricin, has been subjected to structure-antibacterial activity relationship studies. The two Trp residues are very important for antibacterial activity, and analogue studies have demonstrated the significance of the size, shape and aromatic character of the side chains. In the current study we have replaced Trp residues in the model peptide with bulky aromatic amino acids to elucidate further the importance of size and shape. The counterproductive Cys residue in position 3 was also replaced by these aromatic amino acids. The largest aromatic amino acids employed resulted in the most active peptides. The peptides containing these hydrophobic residues were generally more active against Staphylococcus aureus than against Escherichia coli, indicating that the bacterial specificity as well as the antibacterial efficiency can be altered by employing large hydrophobic aromatic amino acid residues. 相似文献
946.
Polycyclic aromatic hydrocarbon-DNA adducts in humans: relevance as biomarkers for exposure and cancer risk 总被引:15,自引:0,他引:15
The methodology applied for DNA adducts in humans has become more reliable in recent years, allowing to detect even background carcinogenic adduct levels in environmentally exposed persons. Particularly, combinations of the various methods now allow the elucidation of specific adduct structures with detection limits of 1 adduct in 108 unmodified nucleotides or even lower. The quantification of polycyclic aromatic hydrocarbon-DNA (PAH-DNA) adducts in human tissues and cells has been achieved with a number of highly sensitive techniques: immunoassays and immunocytochemistry using polyclonal or monoclonal antisera specific for DNA adducts or modified DNA, the 32P-postlabelling assay, and adduct identification using physicochemical instrumentation. The results summarized in this review show that PAH-DNA adducts have been detected in a variety of human tissues, including target organs of PAH- and tobacco-associated cancers. Although dosimetry has not always been precise, a large number of data now clearly show that lowering exposure to carcinogenic PAH results in decreasing PAH-DNA adduct levels. In most studies, however, bulk DNA of a certain tissue or cell type has been examined, and there were relatively few studies in which mutations as a consequence of DNA damage at specific genes have been investigated. Promising as these biomarker studies seem for epidemiology and health surveillance, future biomonitoring and molecular epidemiological studies should be directed to combine several endpoint measurements: i.e., adduct formation (preferably at specific sites), mutational spectra in cancer-relevant genes, and genetic markers of (cancer) susceptibility in a number of cancer-predisposing genes. 相似文献
947.
948.
Oligonucleotide primers were designed from the DNA sequence of the aroA region from Lactococcus lactis and these were used to amplify regions adjacent to the aroA gene. The amplified fragments were cloned to produce a suicide plasmid vector for chromosomal integration. Transformation of L. lactis resulted in a single cross-over homologous recombination event and subsequent excision of the plasmid generated a strain lacking the aroA gene. Growth characteristics indicated that the mutant strain was deficient in aroA. © Rapid Science Ltd. 1998 相似文献
949.
讨论了Phnerochaetechrysosporium木质素降解酶系降解木质素及其模型物的主要特性,催化降解多卤芳香污染物如多卤酚、多卤联苯二喔英以及各种染料的机制和特点。这种处理可以达到理想的降解和矿物化效果,但培养条件和污染物的具体结构对降解有明显影响;与细菌处理相比不产生新的有毒物质,有重要现实意义。P.chrysosporium处理多卤芳香污染物及染料污染物,具不可多得的优势,是解决上述污染潜在重要途径之一。 相似文献
950.
Surfactants are known to increase the apparent aqueous solubility of polycyclic aromatic hydrocarbons (PAHs) and may thus be used to enhance the bioavailability and thereby to stimulate the biodegradation of these hydrophobic compounds. However, surfactants may in some cases reduce or inhibit biodegradation because of toxicity to the bacteria. In this study, toxicity of surfactants on Sphingomonas paucimobilis strain EPA505 and the effect on fluoranthene mineralization were investigated using Triton X-100 as model surfactant. The data showed that amendment with 0.48 mM (0.3 g l-1) of Triton X-100 completely inhibited fluoranthene and glucose mineralization and reduced cell culturability by 100% in 24 h. Electron micrographs indicate that Triton X-100 adversely affects the functioning of the cytoplasmic membrane. However, in the presence of 4.13 mM Ca2+-ions, Triton X-100 more than doubled the maximum fluoranthene mineralization rate and cell culturability was reduced by only 10%. In liquid cultures divalent ions, Ca2+ in particular and Mg2+ to a lesser extent, were thus shown to be essential for the surfactant-enhanced biodegradation of fluoranthene. Most likely the Ca2+-ions stabilized the cell membrane, making the cell less sensitive to Triton X-100. This is the first report on a specific factor which is important for successful surfactant-enhanced biodegradation of PAHs. 相似文献