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1
Magnuson, Jon K., Margaret F. Romine, David R. Burris, and Mark T. Kingsley. "Trichloroethene Reductive Dehalogenase fromDehalococcoides ethenogenes: Sequence of tceA and Substrate Range Characterization." Applied and Environmental Microbiology 66, no. 12 (December 1, 2000): 5141–47. http://dx.doi.org/10.1128/aem.66.12.5141-5147.2000.
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ABSTRACT The anaerobic bacterium Dehalococcoides ethenogenes is the only known organism that can completely dechlorinate tetrachloroethene or trichloroethene (TCE) to ethene via dehalorespiration. One of two corrinoid-containing enzymes responsible for this pathway, TCE reductive dehalogenase (TCE-RDase) catalyzes the dechlorination of TCE to ethene. TCE-RDase dehalogenated 1,2-dichloroethane and 1,2-dibromoethane to ethene at rates of 7.5 and 30 μmol/min/mg, respectively, similar to the rates for TCE,cis-dichloroethene (DCE), and 1,1-DCE. A variety of other haloalkanes and haloalkenes containing three to five carbon atoms were dehalogenated at lower rates. The gene encoding TCE-RDase,tceA, was cloned and sequenced via an inverse PCR approach. Sequence comparisons of tceA to proteins in the public databases revealed weak sequence similarity confined to the C-terminal region, which contains the eight-iron ferredoxin cluster binding motif, (CXXCXXCXXXCP)2. Direct N-terminal sequencing of the mature enzyme indicated that the first 42 amino acids constitute a signal sequence containing the twin-arginine motif, RRXFXK, associated with the Sec-independent membrane translocation system. This information coupled with membrane localization studies indicated that TCE-RDase is located on the exterior of the cytoplasmic membrane. Like the case for the two other RDases that have been cloned and sequenced, a small open reading frame, tceB, is proposed to be involved with membrane association of TCE-RDase and is predicted to be cotranscribed with tceA.
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Zhang, Kegang, Xiaodong Wang, Xiaohui Zhang, and Shengjie Peng. "Degradation of Trichloroethylene in Groundwater Using Iron Catalyzed Calcium Peroxide Systems." E3S Web of Conferences 143 (2020): 02046. http://dx.doi.org/10.1051/e3sconf/202014302046.
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The application of calcium peroxide (CaO2) activated with ferrous ion chelate sodium citrate （TCD）to stimulate the degradation of trichloroethylene (TCE) was investigated. The experimental results show that the removal efficiency of TCE increases first and then decreases with the increase of CaO2 and Na2S2O8 dosage; the chelation ratio of Fe(II)/TCD, too much or too little, will affect the removal efficiency of TCE; when the molar ratio of CaO2/ Fe(II)/ TCD/ TCE is 18/6/6/1, the removal efficiency of TCE is the highest, reaching 97.99% within 200Min. The results demonstrated that the technique of CaO2 activated with ferrous ion is a highly promising technique in in situ chemical oxidation (ISCO) remediation in TCE contaminated sites.
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Bal, C., M. Büyükşekerci, C. Koca, ER Ağış, S. Erdoğan, P. Baran, M. Gündüzöz, and ÖH Yilmaz. "The compromise of dynamic disulfide/thiol homeostasis as a biomarker of oxidative stress in trichloroethylene exposure." Human & Experimental Toxicology 35, no. 9 (July 11, 2016): 915–20. http://dx.doi.org/10.1177/0960327115608928.
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In this study, we aimed to investigate disulfide/thiol homeostasis in trichloroethylene (TCE) exposure. The study was carried out in 30 nonsmoker TCE-exposed workers with a variety of occupations. Additionally, 30 healthy nonsmoker volunteers were recruited as the control group. TCE exposure was determined by measuring urinary trichloroacetic acid (TCA) concentration. Median urinary TCA levels of exposed workers (20.5 mg/L) were significantly higher than control subjects (5 mg/L). Thiol and disulfide concentrations were determined using a novel automated method. Disulfide/thiol ratio was significantly higher in the exposed group ( p < 0.001). Thiol/disulfide homeostasis was found to be disturbed in TCE-exposed workers. We predict that in TCE-exposed workers this disturbance can be a therapeutic target, and the efficiency of the treatment can easily be monitored by the novel method we used.
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Shaw, Bronwen E., Katharina Fleischhauer, Mari Malkki, Theodore Gooley, Elisabetta Zino, Stephen Spellman, Yasuo Morishima, et al. "Permissive HLA-DPB1 Mismatching Compared to a Non-Permissive Mismatching Significantly Improves Overall Survival Following Allogeneic Transplantation In Patients with Both 10/10 and 9/10 Matched Unrelated Donors." Blood 116, no. 21 (November 19, 2010): 227. http://dx.doi.org/10.1182/blood.v116.21.227.227.
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Abstract Abstract 227 It is well established that the use of a donor matched for 9–10/10 alleles at HLA-A,-B,-C,-DRB1,-DQB1 significantly improves overall survival (OS) after unrelated donor (UD) haematopoietic stem cell transplantation (HSCT). Whilst the matching status for HLA-DPB1 alleles has been shown to influence transplant complications (relapse and graft-versus-host disease (GVHD), its impact on survival has not been well defined. The current unmet need in clinical practice is an approach to stratify selection criteria when a clinician is confronted with the choice between several 10/10 or 9/10 matched unrelated donors. There is now considerable interest in exploring different types of matching criteria to define permissive HLA-DPB1 mismatches which may be associated with an improved outcome. We have previously shown that HLA-DPB1 permissiveness can be functionally defined by the characterization of shared T cell epitopes (TCE) recognized by alloreactive T cells. In this model, allelic HLA mismatches are classified as permissive if they do not involve TCE disparities, and as non-permissive if they do. Using this concept, we developed two overlapping algorithms of permissivity for allelic HLA-DPB1 mismatches, on the basis of 3 (TCE3) or 4 (TCE4) groups of DPB1 alleles encoding immunogenic TCE. Data from relatively small prospective studies has shown a worse outcome to be associated with non-permissive DPB1 TCE disparities. Here, we present outcomes in 9123 UD-HSCT pairs, collected through the International Histocompatibility Working Group (IHWG). The cohort was comprised of 5809 10/10 matched transplant pairs and 3314 9/10 matched pairs. Within the 10/10 and 9/10 matched pairs three groups of patients were identified: 1. Zero DPB1 mismatches (i.e. allele matched), 2. Permissive DPB1 mismatch, 3. Non-permissive DPB1 mismatch. The model was adjusted for disease severity, source of stem cells, conditioning regimen, use of T-cell depletion, patient/donor gender and patient age. In line with DPB1 allele frequencies in worldwide populations, the number of transplants scored as permissive was higher for TCE3 (4398/7270 [60.4%]) than for TCE4 (2577/7270 [35.4%]). Using the DPB1 permissive mismatch transplants as the reference group (either 10/10 or 9/10 matched), we showed that DPB1 allelic matches resulted in similar survivals to DPB1 permissive mismatches, both in the 10/10 (HR 0.96, p=0.498 for TCE3 and HR 0.99, p=0.85 for TCE4) and the 9/10 setting (HR 0.97, p=0.70 for TCE3 and HR 0.99, p=0.96 for TCE4). In contrast, survival was significantly worse in the presence of a non-permissive TCE3 or TCE4 mismatch, both in the 10/10 (HR 1.15, p=0.0005 for TCE3 and HR 1.13, p=0.0035 for TCE4) and in the 9/10 matched setting (HR 1.13, p=0.0140 for TCE3 and HR 1.11, p=0.0448 for TCE4). The survival detriment appeared to be due to a significantly increased non-relapse mortality (TCE3: 10/10 HR 1.27, p<0.001 and 9/10 HR 1.21, p=0.0001; TCE4: 10/10 HR 1.24, p<0.001 and 9/10 HR 1.13, p=0.0514), as well as an increase in grades II-IV acute GVHD (TCE3: 10/10 HR 1.17, p<0.001 and 9/10 HR 1.29, p<0.001; TCE4: 10/10 HR 1.12, p=0.0035 and 9/10 HR 1.19, p<0.0001). There was no significant difference in disease relapse between permissive and non-permissive mismatched pairs. Finally, using the 10/10 DPB1 permissive mismatched group as a reference, we found survival to be similar for 10/10 DPB1 non-permissive (HR 1.15) and 9/10 DPB1 permissive (HR 1.20) or DPB1 allele matched (HR 1.17) transplants. In conclusion, our results suggest that extending donor selection to include HLA-DPB1 both allelic and functional TCE matching may result in better prediction of survival for patients. These findings provide an attractive new algorithm to stratify donor choice when several well-matched UD are identified. Disclosures: No relevant conflicts of interest to declare.
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Lee, Patrick K. H., David R. Johnson, Victor F. Holmes, Jianzhong He, and Lisa Alvarez-Cohen. "Reductive Dehalogenase Gene Expression as a Biomarker for Physiological Activity of Dehalococcoides spp." Applied and Environmental Microbiology 72, no. 9 (September 2006): 6161–68. http://dx.doi.org/10.1128/aem.01070-06.
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ABSTRACT This study characterizes the transcriptional expression of the reductive dehalogenase (RDase)-encoding tceA and vcrA genes and evaluates their applicability as potential biological markers of Dehalococcoides activity. When Dehalococcoides ethenogenes 195 was provided with trichloroethene (TCE) as the electron acceptor, the expression of the tceA gene increased by 90-fold relative to that in cells starved of chlorinated ethenes, demonstrating that tceA gene expression is indicative of the active physiological state of this strain. In a Dehalococcoides-containing enrichment culture that contains both the tceA and vcrA genes, the tceA gene was up-regulated in response to TCE and cis-1,2-dichloroethene (cDCE) exposure, while the vcrA gene was up-regulated in response to TCE, cDCE, and vinyl chloride (VC). When chlorinated ethenes were depleted, the RDase-encoding gene transcripts decayed exponentially, with a half-life between 4.8 and 6.1 h, until they reached a stable background level after 2 days. We found that while gene expression correlated generally to the presence of chlorinated ethenes, there was no apparent direct relationship between RDase-encoding transcript numbers and respective rates of TCE, cDCE, and VC dechlorination activities. However, elevated tceA and vcrA expression did correlate with chlorinated-ethene reduction beyond cDCE, suggesting that elevated RDase-encoding transcript numbers could serve as a biomarker for the physiological ability of Dehalococcoides spp. to dechlorinate beyond cDCE.
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Hohmann, Uwe, Winfried Busch, Katia Badaeva, Bernd Friebe, and Bikram S. Gill. "Molecular cytogenetic analysis of Agropyron chromatin specifying resistance to barley yellow dwarf virus in wheat." Genome 39, no. 2 (April 1, 1996): 336–47. http://dx.doi.org/10.1139/g96-044.
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Nine families of bread wheat (TC5, TC6, TC7, TC8, TC9, TC10, TC14, 5395-(243AA), and 5395) with resistance to barley yellow dwarf virus and containing putative translocations between wheat and a group 7 chromosome of Agropyron intermedium (L1 disomic addition line, 7Ai#1 chromosome) induced by homoeologous pairing or tissue culture were analyzed. C-banding, genomic in situ hybridization (GISH), and restriction fragment length polymorphism (RFLP) in combination with repetitive Agropyron-specific sequences and deletion mapping in wheat were used to determine the relative locations of the translocation breakpoints and the size of the transferred alien chromatin segments in hexaploid wheat–Agropyron translocation lines. All homoeologous compensating lines had complete 7Ai#1 or translocated 7Ai#1–7D chromosomes that substitute for chromosome 7D. Two complete 7Ai#1 (7D) substitution lines (5395-(243AA) and 5395), one T1BS–7Ai#1S∙7Ai#1L addition line (TC7), and two different translocation types, T7DS–7Ai#1S∙7Ai#1L (TC5, TC6, TC8, TC9, and TC10) and T7DS∙7DL–7Ai#1L (TC14), substituting for chromosome 7D were identified. The substitution line 5395-(243AA) had a reciprocal T1BS∙1BL–4BS/T1BL–4BS∙4BL translocation. TC14 has a 6G (6B) substitution. The RFLP data from deletion mapping studies in wheat using 37 group 7 clones provided 10 molecular tagged chromosome regions for homoeologous and syntenic group 7 wheat or Agropyron chromosomes. Together with GISH we identified three different sizes of the transferred Agropyron chromosome segments with approximate breakpoints at fraction length (FL) 0.33 in the short arm of chromosome T7DS–7Ai#1S∙7Ai#1L (TC5, TC6, TC8, TC9, and TC10) and another at FL 0.37 of the nonhomoeologous translocated chromosome T1BS–7Ai#1S∙7Ai#1L (TC7). One breakpoint was identified in the long arm of chromosome T7DS∙7DL–7Ai#1L (TC14) at FL 0.56. We detected some nonreciprocal translocations for the most proximal region of the chromosome arm of 7DL, which resulted in small duplications. Key words : C-banding, genomic in situ hybridization (GISH), physical mapping, translocation mapping, RFLP analysis.
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Fisher, Jeffrey W., Stephen R. Channel, Jeffrey S. Eggers, Paula D. Johnson, Kathleen L. MacMahon, Chuck D. Goodyear, Gregory L. Sudberry, D. Alan Warren, John R. Latendresse, and Linda J. Graeter. "Trichloroethylene, Trichloroacetic Acid, and Dichloroacetic Acid: Do They Affect Fetal Rat Heart Development?" International Journal of Toxicology 20, no. 5 (September 2001): 257–67. http://dx.doi.org/10.1080/109158101753252992.
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Trichloroethylene (TCE), trichloroacetic acid (TCA), and dichloroacetic acid (DCA) are commonly found as groundwater contaminants in many regions of the United States. Cardiac birth defects in children have been associated with TCE, and laboratory studies with rodents report an increased incidence of fetal cardiac malformations resulting from maternal exposures to TCE, TCA, and DCA. The objective of this study was to orally treat pregnant CDR(CD) Sprague-Dawley rats with large bolus doses of either TCE (500 mg/kg), TCA (300 mg/kg), or DCA (300 mg/kg) once per day on days 6 through 15 of gestation to determine the effectiveness of these materials to induce cardiac defects in the fetus. All- trans retinoic acid (RA) dissolved in soybean oil was used as a positive control. Soybean oil is commonly used as a dosing vehicle for RA teratology studies and was also used in this study as a dosing vehicle for TCE. Water was used as the dosing vehicle for TCA and DCA. Fetal hearts were examined on gestation day (GD) 21 by an initial in situ, cardiovascular stereomicroscope examination, and then followed by a microscopic dissection and examination of the formalin-fixed heart. The doses selected for TCA and DCA resulted in a modest decrease in maternal weight gain during gestation (3% to 8%). The fetal weights on GD 21 in the TCA and DCA treatment groups were decreased 8% and 9%, respectively, compared to the water control group and 21% in the RA treatment group compared to soybean oil control group. The heart malformation incidence for fetuses from the TCE-, TCA-, and DCA-treated dams did not differ from control values on a per fetus or per litter basis. The rate of heart malformations, on a per fetus basis, ranged from 3% to 5% for TCE, TCA, and DCA treatment groups compared to 6.5% and 2.9% for soybean oil and water control groups. The RA treatment group was significantly higher with 33% of the fetuses displaying heart defects. For TCE, TCA, and DCA treatment groups 42% to 60% of the litters contained at least one fetus with a heart malformation, compared to 52% and 37% of the Utters in the soybean oil and water control groups. For the RA treatment group, 11 of 12 litters contained at least one fetus with a heart malformation. Further research is needed to quantify the spontaneous rates of heart defects for vehicle control rats and to explain the disparity between findings in the present study and other reported findings on the fetal cardiac teratogenicity of TCE, TCA, and DCA.
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Yoshida, M., S. Fukabori, K. Hara, H. Yuasa, K. Nakaaki, Y. Yamamura, and K. Yoshida. "Concentrations of trichloroethylene and its metabolites in blood and urine after acute poisoning by ingestion." Human & Experimental Toxicology 15, no. 3 (March 1996): 254–58. http://dx.doi.org/10.1177/096032719601500312.
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A 58-year-old man fell into a trichloroethylene reservoir bath head first, during a maintenance degreasing bath and accidentally ingested the solvent. Although he showed deep coma, chemical burns and pneumonia on admission, these symptoms gradually subsided. The concentrations of trichloroethylene (TRI) and its metabolites, trichloroethanol (TCE) and trichloroacetic acid (TCA) in blood and urine were measured during hospitalization. Eight hours after the accident, the concentrations ofTRI and its metabolites in serum were 31.4 μ g/ml TRI, 16.5 μg/ ml TCE and 79.5 μg/ml TCA. The serum TRI concentration decreased to 4.3 μg/ml on the following day. Elimination of TCE and TCA from serum occurred biphasically, the estimated half-lives of each metabolites being about 52.6 and 50.4 h in an initial fast phase and 268.3 and 277.2 h in a subsequent slow phase, respectively. Urinary TRI excretion persisted for the first 2 days. The urinary TCE and TCA excretions were longer than that of TRI with a biphasic decrease and the total amount of TCE excreted during the first 2 days was about two times that of TCA. The half-life of urinary TCE excretion (t½ 25.7 h) was shorter than that of TCA (t½ 52.1 h) in the fast phase but did no difference during the slow phase, with each half-time being about 166.3 h. The kinetics of TRI metabolites in blood and urine in this case were in slight agreement with the results following inhalation exposure previously reported in the literature.
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Grostern, Ariel, and Elizabeth A. Edwards. "A 1,1,1-Trichloroethane-Degrading Anaerobic Mixed Microbial Culture Enhances Biotransformation of Mixtures of Chlorinated Ethenes and Ethanes." Applied and Environmental Microbiology 72, no. 12 (October 20, 2006): 7849–56. http://dx.doi.org/10.1128/aem.01269-06.
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ABSTRACT 1,1,1-Trichloroethane (1,1,1-TCA) is a common groundwater pollutant as a result of improper disposal and accidental spills. It is often found as a cocontaminant with trichloroethene (TCE) and inhibits some TCE-degrading microorganisms. 1,1,1-TCA removal is therefore required for effective bioremediation of sites contaminated with mixed chlorinated organics. This study characterized MS, a 1,1,1-TCA-degrading, anaerobic, mixed microbial culture derived from a 1,1,1-TCA-contaminated site in the northeastern United States. MS reductively dechlorinated 1,1,1-TCA to 1,1-dichloroethane (1,1-DCA) and then to monochloroethane (CA) but not further. Cloning of bacterial 16S rRNA genes revealed among other organisms the presence of a Dehalobacter sp. and a Desulfovibrio sp., which are both phylogenetically related to known dehalorespiring strains. Monitoring of these populations with species-specific quantitative PCR during degradation of 1,1,1-TCA and 1,1-DCA showed that Dehalobacter proliferated during dechlorination. Dehalobacter growth was dechlorination dependent, whereas Desulfovibrio growth was dechlorination independent. Experiments were also performed to test whether MS could enhance TCE degradation in the presence of inhibiting levels of 1,1,1-TCA. Dechlorination of cis-dichloroethene (cDCE) and vinyl chloride (VC) in KB-1, a chloroethene-degrading culture used for bioaugmentation, was inhibited with 1,1,1-TCA present. When KB-1 and MS were coinoculated, degradation of cDCE and VC to ethene proceeded as soon as the 1,1,1-TCA was dechlorinated to 1,1-DCA by MS. This demonstrated the potential application of the MS and KB-1 cultures for cobioaugmentation of sites cocontaminated with 1,1,1-TCA and TCE.
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Fung, Jennifer M., Robert M. Morris, Lorenz Adrian, and Stephen H. Zinder. "Expression of Reductive Dehalogenase Genes in Dehalococcoides ethenogenes Strain 195 Growing on Tetrachloroethene, Trichloroethene, or 2,3-Dichlorophenol." Applied and Environmental Microbiology 73, no. 14 (May 18, 2007): 4439–45. http://dx.doi.org/10.1128/aem.00215-07.
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ABSTRACT Reductive dehalogenase (RD) gene transcript levels in Dehalococcoides ethenogenes strain 195 were investigated using reverse transcriptase quantitative PCR during growth and reductive dechlorination of tetrachloroethene (PCE), trichloroethene (TCE), or 2,3-dichlorophenol (2,3-DCP). Cells grown with PCE or TCE had high transcript levels (greater than that for rpoB) for tceA, which encodes the TCE RD, pceA, which encodes the PCE RD, and DET0162, which contains a predicted stop codon and is considered nonfunctional. In cells grown with 2,3-DCP, tceA mRNA was less than 1% of that for rpoB, indicating that its transcription was regulated. pceA and DET0162 were the only RD genes with high transcript levels in cells grown with 2,3-DCP. Proteomic analysis of PCE-grown cells detected both PceA and TceA with high peptide coverage but not DET0162, and analysis of 2,3-DCP-grown cells detected PceA with high coverage but not TceA, DET0162, or any other potential RD. Cells grown with PCE or 2,3-DCP were tested for the ability to dechlorinate PCE, TCE, or 2,3-DCP with H2 as the electron donor. 2,3-DCP-grown cells were unable to dechlorinate TCE but dechlorinated PCE to TCE without a lag, and PCE-grown cells dechlorinated 2,3-DCP without a lag. These results show that 2,3-DCP-grown cells do not produce TceA and that DET0162 is transcribed but its translation product is not detectable in cells and are consistent with PceA's being bifunctional, also serving as the 2,3-DCP RD. Chlorophenols naturally occur in soils and are good candidates for the original substrates for PceA.
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Yaqoob, Noreen, Katarzyna M. Bloch, Andrew R. Evans, and Edward A. Lock. "The effect of trichloroethylene metabolites on the hepatic vitamin B12-dependent methionine salvage pathway and its relevance to increased excretion of formic acid in the rat." Toxicology Research 9, no. 2 (April 2020): 117–26. http://dx.doi.org/10.1093/toxres/tfaa006.
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Abstract The industrial solvent trichloroethylene (TCE) and its two major metabolites trichloroethanol (TCE-OH) and trichloroacetic acid (TCA) cause formic aciduria in male F344 rats. Prior treatment of male F344 rats with 1-aminobenzotriazole a cytochrome P450 inhibitor, followed by TCE (16mk/kg, po), completely prevented formic aciduria, but had no effect on formic acid excretion produced by TCA (8 or 16 mg/kg, po), suggesting TCA may be the proximate metabolite producing this response. Dow and Green reported an increase in the concentration of 5-methyltetrahydrofolate (5-MTHF) in the plasma of rats treated with TCE-OH, suggesting a block in the cycling of 5-MTHF to tetrahydrofolate (THF). This pathway is under the control of the vitamin B12-dependent methionine salvage pathway. We therefore treated rats with three daily doses of methylcobalamin (CH3Cbl) or hydroxocobalamin (OHCbl), a cofactor for methionine synthase, or L-methionine, followed by TCE (16 mg/kg) to determine if they could alleviate the formic aciduria. These pretreatments only partially reduced the excretion of formic acid in the urine. Although prior treatment with S-adenosyl-L-methionine had no effect on formic acid excretion. Consistent with these findings, the activity of methionine synthase in the liver of TCE-treated rats was not inhibited. Transcriptomic analysis of the liver-identified nine differential expressed genes, of note, was downregulation of Lmbrd1 involved in the conversion of vitamin B12 into CH3Cbl, a cofactor for methionine synthase. Our findings indicate that the formic aciduria produced by TCE-OH and TCA may be the result of a block in the recycling of 5-MTHF to THF, the effect on the methionine salvage pathway being a secondary response following acute exposure.
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Rossi, Marta M., Bruna Matturro, Neda Amanat, Simona Rossetti, and Marco Petrangeli Papini. "Coupled Adsorption and Biodegradation of Trichloroethylene on Biochar from Pine Wood Wastes: A Combined Approach for a Sustainable Bioremediation Strategy." Microorganisms 10, no. 1 (January 4, 2022): 101. http://dx.doi.org/10.3390/microorganisms10010101.
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Towards chlorinated solvents, the effectiveness of the remediation strategy can be improved by combining a biological approach (e.g., anaerobic reductive dechlorination) with chemical/physical treatments (e.g., adsorption). A coupled adsorption and biodegradation (CAB) process for trichloroethylene (TCE) removal is proposed in a biofilm–biochar reactor (BBR) to assess whether biochar from pine wood (PWB) can support a dechlorinating biofilm by combining the TCE (100 µM) adsorption. The BBR operated for eight months in parallel with a biofilm reactor (BR)—no PWB (biological process alone), and with an abiotic biochar reactor (ABR)—no dechlorinating biofilm (only an adsorption mechanism). Two flow rates were investigated. Compared to the BR, which resulted in a TCE removal of 86.9 ± 11.9% and 78.73 ± 19.79%, the BBR demonstrated that PWB effectively adsorbs TCE and slows down the release of its intermediates. The elimination of TCE was quantitative, with 99.61 ± 0.79% and 99.87 ± 0.51% TCE removal. Interestingly, the biomarker of the reductive dechlorination process, Dehalococcoides mccartyi, was found in the BRR (9.2 × 105 16S rRNA gene copies/g), together with the specific genes tceA, bvcA, and vcrA (8.16 × 106, 1.28 × 105, and 8.01 × 103 gene copies/g, respectively). This study suggests the feasibility of biochar to support the reductive dechlorination of D. mccartyi, opening new frontiers for field-scale applications.
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Lin, Wen-Yu, Chun-Ping Tu, Hsien-Hua Kuo, and Hsien-Wen Kuo. "Urinary Malondialdehyde (MDA) and N-Acetyl-β-D-Glucosaminidase (NAG) Associated with Exposure to Trichloroethylene (TCE) in Underground Water." Toxics 10, no. 6 (May 29, 2022): 293. http://dx.doi.org/10.3390/toxics10060293.
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Trichloroethylene (TCE) is commonly used in various industries. If wastewater in factories is not effectively treated, the inflow into and subsequent contamination of underground water is likely. Our study assessed the association of exposure to TCE in underground water with oxidative stress and renal tubule damage. We selected 579 residents from areas with underground water contaminated with TCE. Each participant was interviewed via a questionnaire. We also assessed their urinary trichloroacetic acid (TCA) levels by gas chromatography (GC)-FID. Urinary malondialdehyde (MDA) and N-acetyl-β-D-glucosaminidase (NAG) were taken as indicators of oxidative stress and renal tubule damage. We found about 73% of the residents to have consumed underground water. The average duration of consumption was 26 years, with an average of 1.6 L per day. Currently, only 1.5% of the residents still continuously consume underground water. The consumption of underground water positively correlated with heightened urinary TCA levels (r = 0.554). Heightened urinary TCA levels, in turn, were positively associated with NAG levels (r = 0.180) but negatively associated with MDA levels (r = −0.193). The results held even after we had segmented urinary TCA levels into three groups of different levels. The elimination of the source of heightened TCE levels from various industrial effluents is essential. Residents exposed to TCE-laden underground water should periodically undergo health inspections.
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Iheagwam, Franklyn Nonso, Emmanuel Nsedu Israel, Kazeem Oyindamola Kayode, Opeyemi Christianah De Campos, Olubanke Olujoke Ogunlana, and Shalom Nwodo Chinedu. "GC-MS Analysis and Inhibitory Evaluation of Terminalia catappa Leaf Extracts on Major Enzymes Linked to Diabetes." Evidence-Based Complementary and Alternative Medicine 2019 (September 5, 2019): 1–14. http://dx.doi.org/10.1155/2019/6316231.
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Terminalia catappa leaves are used in managing both diabetes mellitus and its complications in Southwest Nigeria. However, its inhibitory activity on enzymes implicated in diabetes is not very clear. This study investigated the in vitro inhibitory properties and mode of inhibition of T. catappa leaf extracts on enzymes associated with diabetes. The study also identified some bioactive compounds as well as their molecular interaction in the binding pocket of these enzymes. Standard enzyme inhibition and kinetics assays were performed to determine the inhibitory effects of aqueous extract (TCA) and ethanol extract (TCE) of T. catappa leaves on α-glucosidase and α-amylase activities. The phytoconstituents of TCA and TCE were determined using GC-MS. Molecular docking of the phytocompounds was performed using Autodock Vina. TCA and TCE were the most potent inhibitors of α-glucosidase (IC50 = 3.28 ± 0.47 mg/mL) and α-amylase (IC50 = 0.24 ± 0.08 mg/mL), respectively. Both extracts displayed a mixed mode of inhibition on α-amylase activity, while mixed and noncompetitive modes of inhibition were demonstrated by TCA and TCE, respectively, on α-glucosidase activity. The GC-MS analytic chromatogram revealed the presence of 24 and 22 compounds in TCE and TCA, respectively, which were identified mainly as phenolic compounds, terpenes/terpenoids, fatty acids, and other phytochemicals. The selected compounds exhibited favourable interactions with the enzymes compared with acarbose. Overall, the inhibitory effect of T. catappa on α-amylase and α-glucosidase may be ascribed to the synergistic action of its rich phenolic and terpene composition giving credence to the hypoglycaemic nature of T. catappa leaves.
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Haest, P. J., D. Springael, P. Seuntjens, and E. Smolders. "Self-inhibition can limit biologically enhanced TCE dissolution from a TCE DNAPL." Chemosphere 89, no. 11 (November 2012): 1369–75. http://dx.doi.org/10.1016/j.chemosphere.2012.05.097.
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Li, Sheng-You, Ze-Kun Sun, Xue-Yi Zeng, Yue Zhang, Meng-Ling Wang, Sheng-Cao Hu, Jun-Rong Song, et al. "Potent Cytotoxicity of Novel L-Shaped Ortho-Quinone Analogs through Inducing Apoptosis." Molecules 24, no. 22 (November 15, 2019): 4138. http://dx.doi.org/10.3390/molecules24224138.
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Twenty-seven L-shaped ortho-quinone analogs were designed and synthesized using a one pot double-radical synthetic strategy followed by removing methyl at C-3 of the furan ring and introducing a diverse side chain at C-2 of the furan ring. The synthetic derivatives were investigated for their cytotoxicity activities against human leukemia cells K562, prostate cancer cells PC3, and melanoma cells WM9. Compounds TB1, TB3, TB4, TB6, TC1, TC3, TC5, TC9, TC11, TC12, TC14, TC15, TC16, and TC17 exhibited a better broad-spectrum cytotoxicity on three cancer cells. TB7 and TC7 selectively displayed potent inhibitory activities on leukemia cells K562 and prostate cancer cells PC3, respectively. Further studies indicated that TB3, TC1, TC3, TC7, and TC17 could significantly induce the apoptosis of PC3 cells. TC1 and TC17 significantly induced apoptosis of K562 cells. TC1, TC11, and TC14 induced significant apoptosis of WM9 cells. The structure-activity relationships evaluation showed that removing methyl at C-3 of the furan ring and introducing diverse side chains at C-2 of the furan ring is an effective strategy for improving the anticancer activity of L-shaped ortho-quinone analogs.
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Ajani, Emmanuel Kolawole, Olugbenga Orisasona, Oladeji Kazeem Kareem, Friday Elijah Osho, Aminat Omosalewa Adeyemo, Bamidele Oluwarotimi Omitoyin, and Abimbola Olumide Adekanmbi. "Growth Performance, Gut Ecology, Immunocompetence and Resistance of Oreochromis niloticus Juveniles Fed Dietary Curcumin longa." Croatian Journal of Fisheries 78, no. 3 (September 1, 2020): 145–56. http://dx.doi.org/10.2478/cjf-2020-0014.
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AbstractThe growth, gut ecology and immunocompetence of Oreochromis niloticus and the resistance to Aeromonas hydrophila were investigated after been fed with diets containing dietary Curcumin longa for 12 weeks. Diets were formulated to contain 30% crude protein with diet TC1, TC2, TC3, TC4 and TC5 having 0% (control), 0.25%, 0.5%, 0.75% and 1.0% turmeric powder, respectively. Diets were allotted to groups of O. niloticus (mean weight of 1.29± 0.15 g) and replicated thrice for 84 days. Results showed that the highest mean final weight (4.79±0.04 g) was obtained in TC3 and corresponded to the treatment with the highest feed intake. A significantly high (p<0.05) specific growth rate (SGR) was observed in TC3 (0.73±0.03 %day−1) while TC4 (0.57±0.02 %day−1) gave the lowest value. The highest microbial load in the gut was observed in TC1 groups and the least in TC4 groups. Red blood cell count, hemoglobin, packed cell volume did not show significant variation (p>0.05) across treatments. However, white blood cell (WBC) count was significantly higher in TC1 (control). There was an improved immunocompetence, as aspartate aminotransferase (AST) progressively reduces in fish fed supplements. Similarly, there was a better oxidative response in the treated groups with reduced hydrogen peroxidase, increased total protein and glutathione peroxidase. Mortality ranged from 25% in TC4 to 95% in TC1 after the challenge test with A. hydrophila. This study showed that C. longa inclusion at 0.5% is more beneficial when growth and health status of O. niloticus juveniles are considered.
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Blanchette, Christopher M., Linda Simoni-Wastila, Fadia T. Shaya, Denise Orwig, Jason Noel, and Bruce Stuart. "Depression Following Thrombotic Cardiovascular Events in Elderly Medicare Beneficiaries: Risk of Morbidity and Mortality." Cardiology Research and Practice 2009 (2009): 1–8. http://dx.doi.org/10.4061/2009/194528.
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Purpose. Depression and antidepressant use may independently increase the risk of acute myocardial infarction and mortality in adults. However, no studies have looked at the effect of depression on a broader thrombotic event outcome, assessed antidepressant use, or evaluated elderly adults.Methods. A cohort of 7,051 community-dwelling elderly beneficiaries who experienced a thrombotic cardiovascular event (TCE) were pooled from the 1997 to 2002 Medicare Current Beneficiary Survey and followed for 12 months. Baseline characteristics, antidepressant utilization, and death were ascertained from the survey, while indexed TCE, recurrent TCE, and depression (within 6 months of indexed TCE) were taken from ICD-9 codes on Medicare claims. Time to death and first recurrent TCE were assessed using descriptive and multivariate statistics.Results. Of the elders with a depression claim, 71.6% had a recurrent TCE and 4.7% died within 12 months of their indexed TCE, compared to 67.6% and 3.9% of those elders without a depression claim. Of the antidepressant users, 72.6% experienced a recurrent TCE and 3.9% died, compared to 73.7% and 4.6% in the subset of selective serotonin reuptake inhibitor (SSRI) users. Depression was associated with a shorter time to death (P=.008) in the unadjusted analysis. However, all adjusted comparisons revealed no effect by depression, antidepressant use, or SSRI use.Conclusions. Depression was not associated with time to death or recurrent TCEs in this study. Antidepressant use, including measures of any antidepressant use and SSRI use, was not associated with shorter time to death or recurrent TCE.
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de Moura, José Carlos, Bruno Lázaro Ramos Rangel, Sheila Cristiane Evangelista Creôncio, and José Ricardo Barros Pernambuco. "Perfil clínico-epidemiológico de traumatismo cranioencefálico do Hospital de Urgências e Traumas no município de Petrolina, estado de Pernambuco." Arquivos Brasileiros de Neurocirurgia: Brazilian Neurosurgery 30, no. 03 (September 2011): 99–104. http://dx.doi.org/10.1055/s-0038-1626501.
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Resumo Objetivo: No Brasil, dentre o conjunto de lesões decorrentes das causas externas, o traumatismo cranioencefálico (TCE) destaca-se em termos de magnitude, tanto em mortos quanto em feridos. Este estudo visa avaliar epidemiologicamente os casos de TCEs ocorridos no Vale do São Francisco, analisando-os quanto a idade, sexo, procedência, etiologia do trauma, conduta e exames complementares. Método: Foram estudados, de forma descritiva e analítica, com abordagem quantitativa, os prontuários dos pacientes vítimas de TCE admitidos no Hospital de Urgências e Traumas, entre os meses de dezembro de 2008 a junho de 2009. No total, foram avaliados 101 prontuários. Conclusão: A etiologia do TCE mais frequente foram os acidentes motociclísticos, seguidos por queda. O sexo masculino é o mais acometido e a faixa etária mais acometida foi a dos 21 aos 40 anos. Com relação à classificação de gravidade do TCEs, 53,47% foram classificados como leves, 25,73%, como moderados e 20,80%, como graves; evidencia-se a prevalência do TCE leve, porém com percentual significativo de casos graves.
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Holmes, Victor F., Jianzhong He, Patrick K. H. Lee, and Lisa Alvarez-Cohen. "Discrimination of Multiple Dehalococcoides Strains in a Trichloroethene Enrichment by Quantification of Their Reductive Dehalogenase Genes." Applied and Environmental Microbiology 72, no. 9 (September 2006): 5877–83. http://dx.doi.org/10.1128/aem.00516-06.
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ABSTRACT While many anaerobic microbial communities are capable of reductively dechlorinating tetrachloroethene (PCE) and trichloroethene (TCE) to dichloroethene (DCE), vinyl chloride (VC), and finally ethene, the accumulation of the highly toxic intermediates, cis-DCE (cDCE) and VC, presents a challenge for bioremediation processes. Members of the genus Dehalococcoides are apparently solely responsible for dechlorination beyond DCE, but isolates of Dehalococcoides each metabolize only a subset of PCE dechlorination intermediates and the interactions among distinct Dehalococcoides strains that result in complete dechlorination are not well understood. Here we apply quantitative PCR to 16S rRNA and reductase gene sequences to discriminate and track Dehalococcoides strains in a TCE enrichment derived from soil taken from the Alameda Naval Air Station (ANAS) using a four-gene plasmid standard. This standard increased experimental accuracy such that 16S rRNA and summed reductase gene copy numbers matched to within 10%. The ANAS culture was found to contain only a single Dehalococcoides 16S rRNA gene sequence, matching that of D. ethenogenes 195, but both the vcrA and tceA reductive dehalogenase genes. Quantities of these two genes in the enrichment summed to the quantity of the Dehalococcoides 16S rRNA gene. Further, between ANAS subcultures enriched on TCE, cDCE, or VC, the relative copy number of the two dehalogenases shifted 14-fold, indicating that the genes are present in two different Dehalococcoides strains. Comparison of cell yields in VC-, cDCE-, and TCE-enriched subcultures suggests that the tceA-containing strain is responsible for nearly all of the TCE and cDCE metabolism in ANAS, whereas the vcrA-containing strain is responsible for all of the VC metabolism.
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Johnson, David R., Patrick K. H. Lee, Victor F. Holmes, Alexander C. Fortin, and Lisa Alvarez-Cohen. "Transcriptional Expression of the tceA Gene in a Dehalococcoides-Containing Microbial Enrichment." Applied and Environmental Microbiology 71, no. 11 (November 2005): 7145–51. http://dx.doi.org/10.1128/aem.71.11.7145-7151.2005.
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ABSTRACT Dynamic changes in the transcriptional expression of the tceA gene, which encodes a trichloroethene reductive dehalogenase, were characterized in a Dehalococcoides-containing microbial enrichment culture. Expression was quantified by real-time PCR as the number of tceA transcripts per tceA gene. Expression of tceA increased 40-fold after chlorinated ethene-starved cells were exposed to trichloroethene (TCE), cis-dichloroethene (DCE), or 1,1-DCE but did not increase after exposure to tetrachloroethene or vinyl chloride. Surprisingly, tceA expression also increased 30-fold after cellular exposure to the nonmetabolic substrate trans-DCE, indicating that expression of tceA is induced by both growth-supporting and non-growth-supporting chlorinated ethenes. Additional experiments revealed that the level of tceA expression was independent of the concentration of chlorinated ethenes (sum concentrations of TCE and DCEs of 2.2 to 333 μM), the concentration of the electron donor hydrogen (concentrations of 12 nM to 17 μM), and the presence of alternate bacterial electron acceptors (5 mM concentrations of fumarate, sulfate, sulfite, thiosulfate, nitrate, or nitrite) but was highly dependent on incubation temperature.
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Woo, Yun. "Transparent Conductive Electrodes Based on Graphene-Related Materials." Micromachines 10, no. 1 (December 26, 2018): 13. http://dx.doi.org/10.3390/mi10010013.
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Transparent conducting electrodes (TCEs) are the most important key component in photovoltaic and display technology. In particular, graphene has been considered as a viable substitute for indium tin oxide (ITO) due to its optical transparency, excellent electrical conductivity, and chemical stability. The outstanding mechanical strength of graphene also provides an opportunity to apply it as a flexible electrode in wearable electronic devices. At the early stage of the development, TCE films that were produced only with graphene or graphene oxide (GO) were mainly reported. However, since then, the hybrid structure of graphene or GO mixed with other TCE materials has been investigated to further improve TCE performance by complementing the shortcomings of each material. This review provides a summary of the fabrication technology and the performance of various TCE films prepared with graphene-related materials, including graphene that is grown by chemical vapor deposition (CVD) and GO or reduced GO (rGO) dispersed solution and their composite with other TCE materials, such as carbon nanotubes, metal nanowires, and other conductive organic/inorganic material. Finally, several representative applications of the graphene-based TCE films are introduced, including solar cells, organic light-emitting diodes (OLEDs), and electrochromic devices.
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Sung, Youlboong, Kirsti M. Ritalahti, Robert P. Apkarian, and Frank E. Löffler. "Quantitative PCR Confirms Purity of Strain GT, a Novel Trichloroethene-to-Ethene-Respiring Dehalococcoides Isolate." Applied and Environmental Microbiology 72, no. 3 (March 2006): 1980–87. http://dx.doi.org/10.1128/aem.72.3.1980-1987.2006.
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ABSTRACT A novel Dehalococcoides isolate capable of metabolic trichloroethene (TCE)-to-ethene reductive dechlorination was obtained from contaminated aquifer material. Growth studies and 16S rRNA gene-targeted analyses suggested culture purity; however, the careful quantitative analysis of Dehalococcoides 16S rRNA gene and chloroethene reductive dehalogenase gene (i.e., vcrA, tceA, and bvcA) copy numbers revealed that the culture consisted of multiple, distinct Dehalococcoides organisms. Subsequent transfers, along with quantitative PCR monitoring, yielded isolate GT, possessing only vcrA. These findings suggest that commonly used qualitative 16S rRNA gene-based procedures are insufficient to verify purity of Dehalococcoides cultures. Phylogenetic analysis revealed that strain GT is affiliated with the Pinellas group of the Dehalococcoides cluster and shares 100% 16S rRNA gene sequence identity with two other Dehalococcoides isolates, strain FL2 and strain CBDB1. The new isolate is distinct, as it respires the priority pollutants TCE, cis-1,2-dichloroethene (cis-DCE), 1,1-dichloroethene (1,1-DCE), and vinyl chloride (VC), thereby producing innocuous ethene and inorganic chloride. Strain GT dechlorinated TCE, cis-DCE, 1,1-DCE, and VC to ethene at rates up to 40, 41, 62, and 127 μmol liter−1 day−1, respectively, but failed to dechlorinate PCE. Hydrogen was the required electron donor, which was depleted to a consumption threshold concentration of 0.76 ± 0.13 nM with VC as the electron acceptor. In contrast to the known TCE dechlorinating isolates, strain GT dechlorinated TCE to ethene with very little formation of chlorinated intermediates, suggesting that this type of organism avoids the commonly observed accumulation of cis-DCE and VC during TCE-to-ethene dechlorination.
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Doyan, Aris, Susilawati Susilawati, Saiful Prayogi, Muhammad Roil Bilad, Muhamad Fatikul Arif, and Noor Maizura Ismail. "Polymer Film Blend of Polyvinyl Alcohol, Trichloroethylene and Cresol Red for Gamma Radiation Dosimetry." Polymers 13, no. 11 (June 4, 2021): 1866. http://dx.doi.org/10.3390/polym13111866.
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This study investigated the polymer film composite of polyvinyl alcohol (PVA), trichlorethylene (TCE) and cresol red (CR) dye irradiated with gamma (γ) rays for potential application as radiation dosimetry. The film was prepared via the solvent-casting method with varying concentrations of TCE. Film samples were exposed to radiation from a γ-rays radiation source of 60Cobalt isotope. Color changes before and after γ-rays irradiation were observed, and the optical properties of the polymer films were investigated by spectrophotometry. Results show that increasing the radiation dose physically changed the color of the polymer film, from purple (pH > 8.8) without radiation (0 kGy) to yellow (almost transparent) (2.8 < pH < 7.2) at the highest dose (12 kGy). The concentration of acid formed due to irradiation increased with the increase in irradiation doses and at higher TCE content. The critical doses of PVA-TCE composites decreased linearly with the increase of TCE composition, facilitating an easy calibration process. The dose response at 438 nm increased exponentially with increasing radiation dose, but showed an opposite trend at the 575 nm band. An increase in the TCA concentration indicated a decrease in the absorption edge and an increase in activation energy, but both decreased for all TCE concentrations at higher doses. The energy gap for the direct and the indirect transitions decreased with increasing TCE concentration and γ-rays radiation dose. The results of this study demonstrated the potential application of PVA-TCE-CR polymer film as γ-rays irradiation dosimetry in a useful dose range of 0–12 kGy.
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Zaleski, J., G. Bator, and R. Jakubas. "Dielectric Properties and Characterisation of the Superionic Phase of [C(NH2)3]2SbCl5*[C(NH2)3]Cl (GHCA)." Zeitschrift für Naturforschung A 50, no. 9 (September 1, 1995): 888–92. http://dx.doi.org/10.1515/zna-1995-0916.
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GHCA undergoes four phase transitions at Tc1 = 402 K, Tc2 = 373 K, Tc3 = 162 K, and Tc4 = 146 K. Below Tc3 it possesses pyroelectric properties with the spontaneous polarization vector (Ps) in the ac plane and the maximum along the c axis equal to 8 μC/m2. Dielectric dispersion studies of GHCA show that the main dielectric dispersion connected probably with collective motions of chlorine ions is above 1GHz. For the phase transition at Tc2 to a superionic phase the thermal dilatation and electric conductivity were measured. The anomalies of the electric conductivity at Tc2 and Tc1 were observed with large values of σ(10-3 S/m) above Tc3. The guanidinium cations above Tc2, besides reorientational motions, undergo slow self diffusion.
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Sekar, Ramanan, Martial Taillefert, and Thomas J. DiChristina. "Simultaneous Transformation of Commingled Trichloroethylene, Tetrachloroethylene, and 1,4-Dioxane by a Microbially Driven Fenton Reaction in Batch Liquid Cultures." Applied and Environmental Microbiology 82, no. 21 (August 19, 2016): 6335–43. http://dx.doi.org/10.1128/aem.02325-16.
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ABSTRACTImproper disposal of 1,4-dioxane and the chlorinated organic solvents trichloroethylene (TCE) and tetrachloroethylene (also known as perchloroethylene [PCE]) has resulted in widespread contamination of soil and groundwater. In the present study, a previously designed microbially driven Fenton reaction system was reconfigured to generate hydroxyl (HO˙) radicals for simultaneous transformation of source zone levels of single, binary, and ternary mixtures of TCE, PCE, and 1,4-dioxane. The reconfigured Fenton reaction system was driven by fed batch cultures of the Fe(III)-reducing facultative anaerobeShewanella oneidensisamended with lactate, Fe(III), and contaminants and exposed to alternating anaerobic and aerobic conditions. To avoid contaminant loss due to volatility, the Fe(II)-generating, hydrogen peroxide-generating, and contaminant transformation phases of the microbially driven Fenton reaction system were separated. The reconfigured Fenton reaction system transformed TCE, PCE, and 1,4-dioxane either as single contaminants or as binary and ternary mixtures. In the presence of equimolar concentrations of PCE and TCE, the ratio of the experimentally derived rates of PCE and TCE transformation was nearly identical to the ratio of the corresponding HO˙ radical reaction rate constants. The reconfigured Fenton reaction system may be applied as anex situplatform for simultaneous degradation of commingled TCE, PCE, and 1,4-dioxane and provides valuable information for future development ofin situremediation technologies.IMPORTANCEA microbially driven Fenton reaction system [driven by the Fe(III)-reducing facultative anaerobeS. oneidensis] was reconfigured to transform source zone levels of TCE, PCE, and 1,4-dioxane as single contaminants or as binary and ternary mixtures. The microbially driven Fenton reaction may thus be applied as anex situplatform for simultaneous degradation of at least three (and potentially more) commingled contaminants. Additional targets forex situandin situdegradation by the microbially driven Fenton reaction developed in the present study include multiple combinations of environmental contaminants susceptible to attack by Fenton reaction-generated HO˙ radicals, including commingled plumes of 1,4-dioxane, pentachlorophenol (PCP), PCE, TCE, 1,1,2-trichloroethane (TCA), and perfluoroalkylated substances (PFAS).
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Faroni, Silvia, Olivier Le Courtois, and Krzysztof Ostaszewski. "Equivalent Risk Indicators: VaR, TCE, and Beyond." Risks 10, no. 8 (July 22, 2022): 142. http://dx.doi.org/10.3390/risks10080142.
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While a lot of research concentrates on the respective merits of VaR and TCE, which are the two most classic risk indicators used by financial institutions, little has been written on the equivalence between such indicators. Further, TCE, despite its merits, may not be the most accurate indicator to take into account the nature of probability distribution tails. In this paper, we introduce a new risk indicator that extends TCE to take into account higher-order risks. We compare the quantiles of this indicator to the quantiles of VaR in a simple Pareto framework, and then in a generalized Pareto framework. We also examine equivalence results between the quantiles of high-order TCEs.
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Johnson, David R., Patrick K. H. Lee, Victor F. Holmes, and Lisa Alvarez-Cohen. "An Internal Reference Technique for Accurately Quantifying Specific mRNAs by Real-Time PCR with Application to the tceA Reductive Dehalogenase Gene." Applied and Environmental Microbiology 71, no. 7 (July 2005): 3866–71. http://dx.doi.org/10.1128/aem.71.7.3866-3871.2005.
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ABSTRACT The accuracy of mRNA quantification by reverse transcription (RT) in conjunction with real-time PCR (qPCR) is limited by mRNA losses during sample preparation (cell lysis, RNA isolation, and DNA removal) and by inefficiencies in reverse transcription. To control for these losses and inefficiencies, a technique was developed that utilizes an exogenous internal reference mRNA (ref mRNA) along with mRNA absolute standard curves. The technique was applied to quantify mRNA of the trichloroethene (TCE) reductive dehalogenase-encoding tceA gene in an anaerobic TCE-to-ethene dechlorinating microbial enrichment. Compared to RT-qPCR protocols that utilize DNA absolute standard curves, application of the new technique increased measured quantities of tceA mRNA by threefold, demonstrating a substantial improvement in quantification. The technique was also effective for quantifying the loss of mRNA during specific steps of the sample processing protocol. Analysis revealed that the efficiency of the RNA isolation (56%) step was significantly less than that of the cell lysis (84%), DNA removal (93%), and RT (88%) steps. The technique was applied to compare the effects of cellular exposure to different chlorinated ethenes on tceA expression. Results show that exposure to TCE or cis-1,2-dichloroethene resulted in 25-fold-higher quantities of tceA mRNA than exposure to vinyl chloride or chlorinated ethene starvation.
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Ayoubi, Patricia J., and Alan R. Harker. "Whole-Cell Kinetics of Trichloroethylene Degradation by Phenol Hydroxylase in a Ralstonia eutropha JMP134 Derivative." Applied and Environmental Microbiology 64, no. 11 (November 1, 1998): 4353–56. http://dx.doi.org/10.1128/aem.64.11.4353-4356.1998.
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ABSTRACT The rate, progress, and limits of trichloroethylene (TCE) degradation by Ralstonia eutropha AEK301/pYK3021 whole cells were examined in the absence of aromatic induction. At TCE concentrations up to 800 μM, degradation rates were sustained until TCE was no longer detectable. TheKs and V max for TCE degradation by AEK301/pYK3021 whole cells were determined to be 630 μM and 22.6 nmol/min/mg of total protein, respectively. The sustained linear rates of TCE degradation by AEK301/pYK3021 up to a concentration of 800 μM TCE suggest that solvent effects are limited during the degradation of TCE and that this construct is little affected by the formation of toxic intermediates at the TCE levels and assay duration tested. TCE degradation by this strain is subject to carbon catabolite repression.
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Lee, S. H., Y. R. Kim, and M. J. Yu. "Competitive removal of VOCs with GAC and BAC following advanced oxidation processes." Water Supply 1, no. 4 (June 1, 2001): 271–78. http://dx.doi.org/10.2166/ws.2001.0093.
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Studies have been conducted to remove trichloroethylene (TCE), tetrachloroethylene (PCE) and 1,1,1-trichloroethane (1,1,1-TCA, TCA) as volatile organic compounds (VOCs) using the combination of chemical oxidation, adsorption by granular activated carbon (GAC) and biological activated carbon (BAC) with a selected microbial consortium (SMC). The purposes of this research were to investigate the competitive removal of VOCs and to develop the most optimal process by using a pilot plant composed of three GAC columns and three BAC columns. Simulated groundwater systems were used not only to examine the competitive adsorption availability for VOCs on GAC and BAC but also to examine the oxidation efficiency using O3 alone and H2O2/O3. The microbial species isolated from the soil contaminated by VOCs were Gram-negative, rod-shaped bacteria, identified as Pseudomonas aeruginosa, Pseudomonas maltophilia, Acinobacter calcoaceticus and Bacillus sphacricus. The results revealed that systems pre-treated by H2O2/O3 were more effective at removing VOCs than systems treated by ozone alone and non-pre-treated systems. The mixture of VOCs was removed in the order of PCE, TCE and TCA in GAC and BAC systems. Biological treatment alone was not effective at removing VOCs. However, pre-treatment of these chemicals by H2O2/O3 showed high removals. PCE and TCA were less effective than TCE at being oxidized by chemical oxidation and biodegradation.
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Abdraboh, M. E., S. H. Abdeen, M. Salama, M. El-Husseiny, Y. M. El-Sherbini, and N. M. Eldeen. "Developmental neurotoxic effects of a low dose of TCE on a 3-D neurosphere system." Biochemistry and Cell Biology 96, no. 1 (February 2018): 50–56. http://dx.doi.org/10.1139/bcb-2017-0089.
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Trichloroethylene (TCE) is one of the industrial toxic byproducts that now persist in the air, soil, and water. Several studies have already illustrated the toxic effect of high doses of TCE on the biological functions of several organs. This study aims to highlight the toxic impact of a low dose of TCE (1 μmol/L) on the development of rat neural stem cells (NSCs). The subventricular zones (SVZ) of rat pup’s brains were collected and minced, and the harvested cells were cultured in the presence of neural growth factors B27/N2 to develop neurospheres. The cells were then exposed to a dose of 1 μmol/L TCE for 1 or 2 weeks. The outcomes indicated a remarkable inhibitory effect of TCE on the differentiation capacity of NSCs, which was confirmed by down-regulation of the astrocyte marker GFAP The inhibitory effect of TCE on the proliferation of NSCs was identified by the reductions in neurosphere diameter, Ki67 expression, and cell cycle arrest at the G1/S phase. Immunolabelling with annexin V indicated the proapoptotic effect of TCE exposure. PCR results revealed a TCE-mediated suppression of the expression of the antioxidant enzyme SOD1. This paper illustrates, for the first time, a detailed examination of the toxic effects of an environmentally low dose of TCE on NCSs at the transcriptional, translational, and functional levels.
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De Moura, José Carlos, Marco Augusto Sobreira Rocha Filho, Aldo Leite Moreira Neto, Raimundo Honorato da Silva Júnior, Fhilipe Xavier Do Sacramento Câmara, and Samuel Miranda De Moura. "Perfil do paciente vítima de traumatismo de crânio no sub-médio do Vale do São Francisco." JBNC - JORNAL BRASILEIRO DE NEUROCIRURGIA 20, no. 4 (March 23, 2018): 415–19. http://dx.doi.org/10.22290/jbnc.v20i4.1003.
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Introdução: O traumatismo crânio-encefálico (TCE) constitui a principal causa de óbitos e seqüelas em pacientes politraumatizados. Entre as principais causas estão: quedas, acidentes motociclísticos, acidentes automobilísticos e agressões. Objetivos: Quantificação dos casos de TCE na região do sub-médio do Vale do São Francisco, qualificação dos seus fatores, além de avaliação das influências interfatoriais. Os resultados foram analisados visando uma orientação para prevenção dos TCEs na região do sub-médio do Vale do São Francisco centrada em Petrolina-PE e Juazeiro-BA. Casuística e métodos: Estudo prospectivo, transversal, descritivo, feito através da coleta de dados sobre os principais aspectos do TCE no Hospital Dom Malan, centro de referência no sub-médio São Francisco, localizado no município de Petrolina-PE, no período de 12 de agosto de 2007 a 12 de novembro de 2007. A pesquisa foi aprovada pelo comitê de ética da Universidade Federal de Pernambuco sob o protocolo número 195/07. Resultados: Dos 158 casos analisados, tem-se que 70,89% sofreram TCE leve; 18,35%, moderado; e 10,76%, grave. A faixa etária predominante foi de 21 a 30 anos, que apresentou um percentil de 29,11%. Dentre as principais causas de TCE, queda e acidente motociclístico foram as mais prevalentes apresentando, respectivamente, 32,91% e 31,01% dos casos. Conclusão: Os acidentes por queda e por motocicleta são as causas mais freqüentes de TCE no submédio do Vale do São Francisco. O consumo de álcool, o uso do capacete e do cinto de segurança figuram entre os maiores determinantes da extensão da gravidade do trauma.
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Siegel, Lenny. "Recent developments: TCE—a call for action." Remediation Journal 17, no. 1 (2006): 135–37. http://dx.doi.org/10.1002/rem.20118.
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Zhang, H., S. Hanada, T. Shigematsu, K. Shibuya, Y. Kamagata, T. Kanagawa, and R. Kurane. "Burkholderia kururiensis sp. nov., a trichloroethylene (TCE)-degrading bacterium isolated from an aquifer polluted with TCE." International Journal of Systematic and Evolutionary Microbiology 50, no. 2 (March 1, 2000): 743–49. http://dx.doi.org/10.1099/00207713-50-2-743.
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Yee, Dennis C., Jennifer A. Maynard, and Thomas K. Wood. "Rhizoremediation of Trichloroethylene by a Recombinant, Root-Colonizing Pseudomonas fluorescensStrain Expressing Toluene ortho-Monooxygenase Constitutively." Applied and Environmental Microbiology 64, no. 1 (January 1, 1998): 112–18. http://dx.doi.org/10.1128/aem.64.1.112-118.1998.
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ABSTRACT Trichloroethylene (TCE) was removed from soils by using a wheat rhizosphere established by coating seeds with a recombinant, TCE-degrading Pseudomonas fluorescens strain that expresses the tomA + (tolueneo-monooxygenase) genes from Burkholderia cepacia PR123(TOM23C). A transposon integration vector was used to insert tomA +into the chromosome of P. fluorescens 2-79, producing a stable strain that expressed constitutively the monooxygenase at a level of 1.1 nmol/min · mg of protein (initial TCE concentration, 10 μM, assuming that all of the TCE was in the liquid) for more than 280 cell generations (36 days). We also constructed a salicylate-inducible P. fluorescens strain that degraded TCE at an initial rate of 2.6 nmol/min · mg of protein in the presence of 10 μM TCE [cf. B. cepacia G4 PR123(TOM23C), which degraded TCE at an initial rate of 2.5 nmol/min · mg of protein]. A constitutive strain,P. fluorescens 2-79TOM, grew (maximum specific growth rate, 0.78 h−1) and colonized wheat (3 × 106CFU/cm of root) as well as wild-type P. fluorescens 2-79 (maximum specific growth rate, 0.77 h−1; level of colonization, 4 × 106 CFU/cm of root). Rhizoremediation of TCE was demonstrated by using microcosms containing the constitutive monooxygenase-expressing microorganism, soil, and wheat. These closed microcosms degraded an average of 63% of the initial TCE in 4 days (20.6 nmol of TCE/day · plant), compared to the 9% of the initial TCE removed by negative controls consisting of microcosms containing wild-type P. fluorescens2-79-inoculated wheat, uninoculated wheat, or sterile soil.
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Friedrich, Mirco, Paola Neri, Noemie Leblay, Niklas Kehl, Julius Michel, Holly Lee, Elie Barakat, et al. "Mapping the Multiple Myeloma T Cell Landscape By Immunotherapeutic Perturbation Reveals Mechanism and Determinants of Response to Bispecific T Cell Engagers." Blood 138, Supplement 1 (November 5, 2021): 731. http://dx.doi.org/10.1182/blood-2021-152149.
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Abstract Immunotherapies have transformed the clinical care of patients with cancer. Bispecific T cell engagers (TCEs) have recently entered early-phase clinical trials of multiple myeloma (MM) and shown remarkable response rates even in heavily pretreated patients. However, T cells are heterogeneous with respect to phenotype, function and specificity for tumor antigens and currently we have limited understanding how to identify and monitor tumor specific T cells in hematological malignancies. It is furthermore unclear why individual patients fail to elicit an antitumor immune response upon treatment with TCEs and whether a persistent T cell response to TCEs relies on reinvigoration of pre-existing tumor-infiltrating lymphocytes or on recruitment of novel T cells. Here we performed longitudinal paired single-cell RNA and T cell receptor (TCR) sequencing on >100,000 immune cells from patients with MM before, during and after TCE therapy. We defined transcriptional gradients of MM-infiltrating immune cells between n=5 healthy bone marrow donors, n=10 newly diagnosed MM patients and n=11 refractory MM patients undergoing immunotherapy with bispecific BCMA-targeting antibodies. By tracking T cell clones over time using their TCR as individual barcode, we further integrated these longitudinal in vivo data with protein-level analysis and functional validation in MM bone-marrow cultures exposed to TCEs. Refractory MM patients exhibited a highly individual bone-marrow immune composition, that was significantly perturbed compared to healthy or diseased, but therapy-naïve bone marrow. We observed that the inter-patient heterogeneity in the T cell landscape composition is superimposed by conserved TCR repertoire dynamics forming a trajectory between early anti-tumor effector states and exhaustion. In all patients, we observed a dichotomy of TCE-responsive versus TCE-refractory T cell clones. Longitudinal tracking of TCE-responsive T cell clones and their transcriptional phenotypes revealed coupling of tumor recognition, clonal expansion and T cell dysfunction marked by expression of cytotoxicity (GZMB, GNLY) and terminal exhaustion markers, such as TOX and CD39. Significant clonal replacement of T cells was evident in n=5 clinically responding patients with MM throughout continued TCE therapy and driven by a subset of non-exhausted, naïve-like CD8 + T cells. The top 1% TCE-responsive clones were fate-determined and either followed a memory-exhaustion or cytotoxicity trajectory. Patients who did not respond to TCE therapy exhibited a dysfunctional T cell landscape before therapy that limited clonal expansion and TCR persistence. As proof-of-concept, we matched single-cell profiling data of n=10 individual patients with protein-level analysis and functional validation of TCE-driven T cell expansion in vitro, providing the first signals of preferential expansion of specific fate- and avidity-determined clones upon TCE-mediated stimulation. We propose the mode of action of TCE therapy in MM to be driven by pre-existing T cell fate commitments that determine clonotype diversification and persistence, and ultimately, clinical response. Our results further demonstrate that clinical TCE response derives from a distinct repertoire of pre-existing T cell clones, whereas other clonotypes are functionally excluded from the repertoire and subsequently lost during therapy. We define the determinants of response to TCE treatment to be inherent to the individual's T cell repertoire before therapy. Our results provide the rationale for response prediction and monitoring of future immunotherapy approaches in MM patients beyond TCE therapy. Figure 1 Figure 1. Disclosures Neri: BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Goldschmidt: Amgen: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Adaptive Biotechnology: Consultancy; Celgene: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; BMS: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Chugai: Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; GSK: Honoraria; Incyte: Research Funding; Janssen: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Johns Hopkins University: Other: Grant; Molecular Partners: Research Funding; MSD: Research Funding; Mundipharma: Research Funding; Novartis: Honoraria, Research Funding; Dietmar-Hopp-Foundation: Other: Grant; Sanofi: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Takeda: Consultancy, Research Funding. Weinhold: Sanofi: Honoraria. Raab: Abbvie: Consultancy, Honoraria; Roche: Consultancy; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees. Bahlis: Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genentech: Consultancy; Janssen: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria.
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Park, Joonhong, Jerome J. Kukor, and Linda M. Abriola. "Characterization of the Adaptive Response to Trichloroethylene-Mediated Stresses in Ralstonia pickettii PKO1." Applied and Environmental Microbiology 68, no. 11 (November 2002): 5231–40. http://dx.doi.org/10.1128/aem.68.11.5231-5240.2002.
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ABSTRACT In Ralstonia pickettii PKO1, a denitrifying toluene oxidizer that carries a toluene-3-monooxygenase (T3MO) pathway, the biodegradation of toluene and trichloroethylene (TCE) by the organism is induced by TCE at high concentrations. In this study, the effect of TCE preexposure was studied in the context of bacterial protective response to TCE-mediated toxicity in this organism. The results of TCE degradation experiments showed that cells induced by TCE at 110 mg/liter were more tolerant to TCE-mediated stress than were those induced by TCE at lower concentrations, indicating an ability of PKO1 to adapt to TCE-mediated stress. To characterize the bacterial protective response to TCE-mediated stress, the effect of TCE itself (solvent stress) was isolated from TCE degradation-dependent stress (toxic intermediate stress) in the subsequent chlorinated ethylene toxicity assays with both nondegradable tetrachloroethylene and degradable TCE. The results of the toxicity assays showed that TCE preexposure led to an increase in tolerance to TCE degradation-dependent stress rather than to solvent stress. The possibility that such tolerance was selected by TCE degradation-dependent stress during TCE preexposure was ruled out because a similar extent of tolerance was observed in cells that were induced by toluene, whose metabolism does not produce any toxic products. These findings suggest that the adaptation of TCE-induced cells to TCE degradation-dependent stress was caused by the combined effects of solvent stress response and T3MO pathway expression.
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Liang, Xiaoming, Olivia Molenda, Shuiquan Tang, and Elizabeth A. Edwards. "Identity and Substrate Specificity of Reductive Dehalogenases Expressed in Dehalococcoides-Containing Enrichment Cultures Maintained on Different Chlorinated Ethenes." Applied and Environmental Microbiology 81, no. 14 (May 1, 2015): 4626–33. http://dx.doi.org/10.1128/aem.00536-15.
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ABSTRACTMany reductive dehalogenases (RDases) have been identified in organohalide-respiring microorganisms, and yet their substrates, specific activities, and conditions for expression are not well understood. We tested whether RDase expression varied depending on the substrate-exposure history of reductive dechlorinating communities. For this purpose, we used the enrichment culture KB-1 maintained on trichloroethene (TCE), as well as subcultures maintained on the intermediatescis-dichloroethene (cDCE) and vinyl chloride (VC). KB-1 contains a TCE-to-cDCE dechlorinatingGeobacterand severalDehalococcoidesstrains that together harbor many of the known chloroethene reductases. Expressed RDases were identified using blue native polyacrylamide gel electrophoresis, enzyme assays in gel slices, and peptide sequencing. As anticipated but never previously quantified, the RDase fromGeobacterwas only detected transiently at the beginning of TCE dechlorination. TheDehalococcoidesRDase VcrA and smaller amounts of TceA were expressed in the parent KB-1 culture during complete dechlorination of TCE to ethene regardless of time point or amended substrate. TheDehalococcoidesRDase BvcA was only detected in enrichments maintained on cDCE as growth substrates, in roughly equal abundance to VcrA. Only VcrA was detected in subcultures enriched on VC. Enzyme assays revealed that 1,1-DCE, a substrate not used for culture enrichment, afforded the highest specific activity.trans-DCE was substantially dechlorinated only by extracts from cDCE enrichments expressing BvcA. RDase gene distribution indicated enrichment of different strains ofDehalococcoidesas a function of electron acceptor TCE, cDCE, or VC. Each chloroethene reductase has distinct substrate preferences leading to strain selection in mixed communities.
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Meermeier, Erin W., Seth J. Welsh, Meaghen Sharik, Megan T. Du, Chang-Xin Shi, Bryant Chau, Feng Wang, et al. "Abstract 5588: PD-1 blockade synergizes with IMiDs to enhance bispecific T cell engager immune responses to Vk*MYChCRBN multiple myeloma by preventing T cell exhaustion." Cancer Research 82, no. 12_Supplement (June 15, 2022): 5588. http://dx.doi.org/10.1158/1538-7445.am2022-5588.
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Abstract Bispecific T cell engagers (TCE) are novel immunotherapies for cancer that redirect a synthetic immune response against tumors. Early clinical trial data show that BCMA-targeting TCEs are highly effective immunotherapies for treating relapsed and refractory multiple myeloma (MM). Thus, it is important to define combinatorial approaches that increase the efficacy and durability of TCE. We recently investigated a murine anti-BCMA TCE in the immunocompetent IMiD-sensitive Vk*MYChCRBN model of MM. Our data show that anti-BCMA TCE was safe and efficacious in most mice, but failed in those with high-tumor burden, consistent with clinical reports of TCE in leukemia. We tested the combination of anti-BCMA TCE and IMiDs to provide an additive anti-tumor effect and stimulatory cytokines, such as IL-2 in the tumor environment. This combination expanded cytolytic T cells and improved activity even in IMiD-resistant high-tumor burden cases. Yet, survival was only marginally extended due to T cell exhaustion. We hypothesized that blockade of the inhibitory immune checkpoint PD-1 would synergize with TCE and IMiDs to potentiate the response directed by the TCE by reinvigorating exhausted T cells. We evaluated the efficacy of the triple therapy combination in Vk*MYChCRBN: the anti-BCMA TCE, pomalidomide, and anti-PD1. Checkpoint blockade alone, or in combination with TCE did not improve tumor control or survival compared to control treatments. The triple combination proved most effective at controlling tumor growth, inducing a complete response after 2 weeks of treatment, and was curative in 40% of the mice. Longitudinal analysis of the immune response showed that the addition of anti-PD1 to TCE-IMiDs rescued T cell expansion at tumor sites and sustained expression of activation markers after repeated doses. Longitudinal analysis of blood and bone marrow (BM) cytokines showed the typical profile associated with cytokine release syndrome (CRS) during T cell immunotherapy. Of note, we observed IL-2, IFN-γ, and GM-CSF production was sustained in the BM tumor environment in the triple combination. We suspect that these cytokines, especially IL-2, are key to sustaining non-exhausted effector T cell proliferation in response to TCE therapy. Expectedly, we observed toxicity with the elevated cytokine release in the triple combination. that we anticipate could be controlled with step-up dosing or CRS mitigation treatment. We conclude that combination of PD1 blockade, IMiDs and TCE provides superior efficacy in the immunocompetent preclinical model of MM, Vk*MYChCRBN, while increasing inflammatory pathways that can lead to CRS. Finally, as we found this combination to be curative in some mice, we will investigate whether this combination immunotherapy also enhanced an endogenous anti-tumor immune response leading to protective immunosurveillance. Citation Format: Erin W. Meermeier, Seth J. Welsh, Meaghen Sharik, Megan T. Du, Chang-Xin Shi, Bryant Chau, Feng Wang, Matthew Wheeler, Natalie Bezman, Pavel Strop, P. Leif Bergsagel, Marta Chesi. PD-1 blockade synergizes with IMiDs to enhance bispecific T cell engager immune responses to Vk*MYChCRBN multiple myeloma by preventing T cell exhaustion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5588.
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Ginting, Binawati, Ilham Maulana, Nurdin Saidi, and Syarifah Yanti Astryna. "ISOLATION AND ACTIVITY ANTIOXIDANT TEST OF COCOA POD HUSK ETHYL ASETAT EXTRACTS (Theobroma cacao L)." Jurnal Natural 19, no. 2 (June 30, 2019): 49–53. http://dx.doi.org/10.24815/jn.v19i2.12568.
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Isolation and testing of antioxidant activity with1,1-difenil-2-pikril hidrazil (DPPH) from ethyl acetate extract ofcocoa pod husk(Theobroma cacao L) has been carried out.Theobroma cacaoextract (TCE) showed highly strong antioxidant activity with IC50 = 8,75 ppm and vitamine C = 6,07 ppm as positive control. Isolation of the active components of TCE by column chromatography using silica gel absorbent 60 mesh ASTM (Merck 774) and the eluent n-hexane: ethyl acetate (9:1), obtained 7 fraction combined (TCE 1 to TCE 7). There are 6 combined fractions having the potential as antioxidants, namely TCE 2 to TCE 7 with a range of IC50 (6,46 ppm – 91,8 ppm). TCE 2 fraction has a very strong antioxidant activity with IC50 = 6,46 ppm. Separation of TCE 2 fraction on silica column chromatography obtained 4 combined fractions (TCE 2.1 to TCE 2.4). The test results of antioxidant activity showed that TCE 2.4 had very strong activity with IC50 = 42,7 ppm.For the TCE 2.2 fraction, preparative TLC was carried out using eluent n-hexane: ethyl acetate (9.5: 0,5) obtained by TCE 2.2.4 isolate with a melting point of 114-120 °C and was a steroid class.
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Wang, Sih Yu, Zong Han Yang, Jian Li Lin, Tzu Hsin Lee, and Chih Ming Kao. "Site Characterization and Optimization of Corrective Actions at a Chlorinated-Solvent Spill Site." Advanced Materials Research 1030-1032 (September 2014): 174–77. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.174.
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The industrial solvent, trichloroethene (TCE), is among the most ubiquitous chlorinated compounds found in subsurface contamination. Operation of an avionics repair shop at a military base has resulted in past release of solvent chemicals including TCE and other chlorinated aliphatic hydrocarbons. The objectives of this study were to investigate the occurrence of natural remediation process and the feasibility of using natural remediation as the remedial option at this site. The following tasks have been performed: (1) site characterization to delineate the lateral and vertical extent of contaminants in the subsurface; (2) field investigation of natural remediation; and (3) efficiency of TCE removal through natural remediation in the field. Results indicate that TCE biodegradation occurred at this site, and natural remediation is a possible remedial alternative for TCE plume containment. Evidences for the TCE natural remediation included: (1) decreased TCE and other chlorinated compounds concentrations along the transport path; (2) production of the TCE degradation byproducts (including ethane); (3) decreased total organic carbon along the transport path, (4) deceased pH in the spill source area; (5) production of chloride ion and carbon dioxide. Experiences obtained from this study would be helpful in developing a site remedial protocol for other DNAPL sites.
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Pour, Sadaf Marashi, Ian Woolley, Peter Canavan, John Chuah, Darren B. Russell, Matthew Law, and Kathy Petoumenos. "Triple class experience after initiation of combination antiretroviral treatment in Australia: survival and projections." Sexual Health 8, no. 3 (2011): 295. http://dx.doi.org/10.1071/sh10008.
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Background Patients who have become triple class experienced (TCE) are at a high risk of exhausting available treatment options. This study aims to investigate factors associated with becoming TCE and to explore the effect of becoming TCE on survival. We also project the prevalence of TCE in Australia to 2012. Methods: Patients were defined as TCE when they stopped a combination antiretroviral treatment (cART) that introduced the third of the three major antiretroviral classes. Cox proportional hazards models were used to investigate factors associated with TCE and the effect of TCE on survival. To project TCE prevalence, we used predicted rates of TCE by fitting a Poisson regression model, together with the estimated number of patients who started cART in each year in Australia, assuming a mortality rate of 1.5 per 100 person-years. Results: Of the 1498 eligible patients, 526 became TCE. Independent predictors of a higher risk of TCE included current CD4 counts below 200 cells μL–1 and earlier calendar periods. No significant difference in survival was observed between those who were TCE and those who were not yet TCE. An increasing number of patients are using cART in Australia and if current trends continue, the number of patients who are TCE is estimated to increase from 2800 in 2003 to 5000 in 2012. Conclusion: Our results suggest that the prevalence of TCE in Australia is estimated to plateau after 2003. However, as an increasing number of patients are becoming TCE, it is necessary to develop new drugs that come from new classes or do not have overlapping resistance.
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Ye, Mingzhu, Jian Xiong, Fang Zhao, Shanshan Sun, Lecong Wang, and Guohua Zheng. "Comparison of Traditional Chinese Exercises and Nontraditional Chinese Exercise Modalities on Cognitive and Executive Function in Community Middle-Aged and Older Adults: A Cross-Sectional Study." Evidence-Based Complementary and Alternative Medicine 2020 (November 22, 2020): 1–9. http://dx.doi.org/10.1155/2020/4380805.
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Background. Current evidence indicates that regular exercise can have a positive impact on cognitive function in older adults, but whether different exercise modalities may induce differential protective effects in different cognitive domains is uncertain. Objective. To compare the effect of traditional Chinese exercise (TCE) modalities and non-traditional Chinese exercise (non-TCE) modalities on cognitive and executive function in community middle-aged and older adults through a cross-sectional study. Methods. A total of 350 community middle-aged and older adults aged over 55 years participated in this study. Information on demographic characteristics, lifestyle and behavioural habits, and regular exercise was collected by a self-designed questionnaire. Global cognitive ability and executive function were assessed using the Montreal Cognitive Assessment (MoCA) scale, the clock drawing test (CDT), the animal naming test (ANT), and the trail making test (TMT). Eligible subjects were categorized into the no regular exercise (no-RE), non-TCE, or TCE groups according to their self-reported exercise information. Comparisons of global cognitive and executive function among the three groups were conducted using ANOVA or the general linear model with adjustment for potential confounding factors. Results. The results showed that for the non-TCE or TCE groups, the MoCA and CDT scores were significantly higher, and the TMT-A test time was significantly shorter than those in the no-RE group (all P < 0.05 ), but no significant difference was observed for the TMT-B and ANT tests. After adjustment for potential confounding factors, the MoCA, the CDT, and TMT-A scores in the TCE group were significant compared to those in the no-RE group. In addition, subgroup analysis showed that in the TCE group, the MoCA scores were significantly higher than those in the non-TCE group. Furthermore, in the TCE group, the CDT scores for those with an exercise duration of <5 years were higher and the TMT-A test time for those with an exercise duration of ≥5 years was shorter than those in the non-TCE group. Conclusions. Both TCE and non-TCE have potential protective effects on global cognitive and executive function in community middle-aged and older adults. Compared to the non-TCE modality, the TCE modality may have a more positive association with these protective effects. Furthermore, prospective studies are needed to confirm these findings.
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Kitajima, Eiichi, Hitoshi Murayama, Tetsuya Kobayashi, and Hiroaki Yagoh. "Mass Balance of Trichloroethylene (TCE) in A Hardware Factory Which Installed TCE Withdrawal Device of Exhaust Gas." Journal of Environmental Chemistry 1, no. 3 (1991): 553–57. http://dx.doi.org/10.5985/jec.1.553.
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K, C. M., and L. Yang. "Enhanced bioremediation of trichloroethene contaminated by a biobarrier system." Water Science and Technology 42, no. 3-4 (August 1, 2000): 429–34. http://dx.doi.org/10.2166/wst.2000.0414.
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The industrial solvent trichloroethylene (TCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. The objective of this study was to develop a barrier system, which includes a peat (used as the primary substrates) layer to enhance the aerobic cometabolism of TCE in situ. A laboratory-scale column experiment was conducted to evaluate the feasibility of using this peat biobarrier to remediate aquifers contaminated by TCE. This system was performed using a series of continuous-flow glass columns including a soil column, a peat column, followed by two consecutive soil columns. Activated sludges were inoculated in all three soil columns to provide microbial consortia for TCE cometabolism. Simulated TCE contaminated groundwater with a flow rate of 0.25 L/day was pumped into the system. Effluent samples from each column were analyzed for TCE and its degradation byproducts [cis-dichloroethylene (cis-DCE) and vinyl chloride (VC)]. Average removal efficiency was 96% for TCE over a 60-day operating period. Accumulation of VC was observed due to the depletion of oxygen in the system. Results from this laboratory study reveal that the developed biobarrier treatment scheme would be expected to provide a more cost-effective alternative to remediate chlorinated-solvent contaminated aquifers.
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Weyens, Nele, Bram Beckers, Kerim Schellingen, Reinhart Ceulemans, Daniel van der Lelie, Lee Newman, Safiyh Taghavi, Robert Carleer, and Jaco Vangronsveld. "The Potential of the Ni-Resistant TCE-DegradingPseudomonas putidaW619-TCE to Reduce Phytotoxicity and Improve Phytoremediation Efficiency of Poplar Cuttings on A Ni-TCE Co-Contamination." International Journal of Phytoremediation 17, no. 1 (August 12, 2014): 40–48. http://dx.doi.org/10.1080/15226514.2013.828016.
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Li, Cui, Rong Chen, Hui Liu, Yao Huang, Jintao Yu, Weiwei Ouyang, and Chen Xue. "Response of chlorinated hydrocarbon transformation and microbial community structure in an aquifer to joint H2 and O2." RSC Advances 12, no. 36 (2022): 23252–62. http://dx.doi.org/10.1039/d2ra04185e.
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The joint H2/O2 can promote the transformation of TCE, tDCE and CF. A specific microbial community with higher diversity forms in the H2/O2 microcosm, and synchronously increases the anaerobic tceA and aerobic phe and soxB genes.
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Gerritse, Jan, Oliver Drzyzga, Geert Kloetstra, Mischa Keijmel, Luit P. Wiersum, Roger Hutson, Matthew D. Collins, and Jan C. Gottschal. "Influence of Different Electron Donors and Acceptors on Dehalorespiration of Tetrachloroethene byDesulfitobacterium frappieri TCE1." Applied and Environmental Microbiology 65, no. 12 (December 1, 1999): 5212–21. http://dx.doi.org/10.1128/aem.65.12.5212-5221.1999.
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ABSTRACT Strain TCE1, a strictly anaerobic bacterium that can grow by reductive dechlorination of tetrachloroethene (PCE) and trichloroethene (TCE), was isolated by selective enrichment from a PCE-dechlorinating chemostat mixed culture. Strain TCE1 is a gram-positive, motile, curved rod-shaped organism that is 2 to 4 by 0.6 to 0.8 μm and has approximately six lateral flagella. The pH and temperature optima for growth are 7.2 and 35°C, respectively. On the basis of a comparative 16S rRNA sequence analysis, this bacterium was identified as a new strain of Desulfitobacterium frappieri, because it exhibited 99.7% relatedness to the D. frappieri type strain, strain PCP-1. Growth with H2, formate,l-lactate, butyrate, crotonate, or ethanol as the electron donor depends on the availability of an external electron acceptor. Pyruvate and serine can also be used fermentatively. Electron donors (except formate and H2) are oxidized to acetate and CO2. When l-lactate is the growth substrate, strain TCE1 can use the following electron acceptors: PCE and TCE (to produce cis-1,2-dichloroethene), sulfite and thiosulfate (to produce sulfide), nitrate (to produce nitrite), and fumarate (to produce succinate). Strain TCE1 is not able to reductively dechlorinate 3-chloro-4-hydroxyphenylacetate. The growth yields of the newly isolated bacterium when PCE is the electron acceptor are similar to those obtained for other dehalorespiring anaerobes (e.g.,Desulfitobacterium sp. strain PCE1 andDesulfitobacterium hafniense) and the maximum specific reductive dechlorination rates are 4 to 16 times higher (up to 1.4 μmol of chloride released · min−1 · mg of protein−1). Dechlorination of PCE and TCE is an inducible process. In PCE-limited chemostat cultures of strain TCE1, dechlorination is strongly inhibited by sulfite but not by other alternative electron acceptors, such as fumarate or nitrate.
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Magnuson, Jon K., Robert V. Stern, James M. Gossett, Stephen H. Zinder, and David R. Burris. "Reductive Dechlorination of Tetrachloroethene to Ethene by a Two-Component Enzyme Pathway." Applied and Environmental Microbiology 64, no. 4 (April 1, 1998): 1270–75. http://dx.doi.org/10.1128/aem.64.4.1270-1275.1998.
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ABSTRACT Two membrane-bound, reductive dehalogenases that constitute a novel pathway for complete dechlorination of tetrachloroethene (perchloroethylene [PCE]) to ethene were partially purified from an anaerobic microbial enrichment culture containing Dehalococcoides ethenogenes 195. When titanium(III) citrate and methyl viologen were used as reductants, PCE-reductive dehalogenase (PCE-RDase) (51 kDa) dechlorinated PCE to trichloroethene (TCE) at a rate of 20 μmol/min/mg of protein. TCE-reductive dehalogenase (TCE-RDase) (61 kDa) dechlorinated TCE to ethene. TCE,cis-1,2-dichloroethene, and 1,1-dichloroethene were dechlorinated at similar rates, 8 to 12 μmol/min/mg of protein. Vinyl chloride and trans-1,2-dichloroethene were degraded at rates which were approximately 2 orders of magnitude lower. The light-reversible inhibition of TCE-RDase by iodopropane and the light-reversible inhibition of PCE-RDase by iodoethane suggest that both of these dehalogenases contain Co(I) corrinoid cofactors. Isolation and characterization of these novel bacterial enzymes provided further insight into the catalytic mechanisms of biological reductive dehalogenation.
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Ding, Yuan Hong, Qing Wang, Hong Qiang Ren, and Jian Lu. "Effects of Trichloroethylene on the Wastewater Treatment in Membrane Bioreactors." Advanced Materials Research 588-589 (November 2012): 34–38. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.34.
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The activities of nitrifying bacteria and organic utilizing bacteria against TCE in sludge was investigated using three series of Membrane bioreactors, and the results indicated that, the removal efficiencies of COD decreased gradually, but was not affected severely with TCE inhibition, good organics removal efficiencies was possibly realized, while the ammonia removal efficiencies dropped sharply due to the severe inhibition of TCE against nitrifying bacteria, the degree of TCE inhibition against nitrifying bacteria increased with the TCE concentration, but low-concentration TCE addition seems act as a chronic toxicity to the sludge activity, However, the nitrifying bacteria was gradually adapted to the TCE inhibition and its activities could be entirely resumed, and the ability of the nitrifying sludge to tolerate TCE could be satisfactory maintained either after the stop of TCE addition, therefore, TCE could be degradated partly by the nitrification processes, when the TCE was added intermittently and continuously into the Membrane reactors, simultaneously, a good performance of nitrification and organic utilization processes was possibly maintained stably.