scholarly journals Aerobic Biodegradation of Methyltert-Butyl Ether by Aquifer Bacteria from Leaking Underground Storage Tank Sites

2001 ◽  
Vol 67 (12) ◽  
pp. 5824-5829 ◽  
Author(s):  
S. R. Kane ◽  
H. R. Beller ◽  
T. C. Legler ◽  
C. J. Koester ◽  
H. C. Pinkart ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Butyl Alcohol ◽  
Water Soluble ◽  
Aerobic Biodegradation ◽  
Butyl Ether ◽  
Degrading Bacterium ◽  
In Situ Conditions ◽  
Molecular Phylogenetic ◽  
Mtbe Degradation

ABSTRACT The potential for aerobic methyl tert-butyl ether (MTBE) degradation was investigated with microcosms containing aquifer sediment and groundwater from four MTBE-contaminated sites characterized by oxygen-limited in situ conditions. MTBE depletion was observed for sediments from two sites (e.g., 4.5 mg/liter degraded in 15 days after a 4-day lag period), whereas no consumption of MTBE was observed for sediments from the other sites after 75 days. For sediments in which MTBE was consumed, 43 to 54% of added [U-14C]MTBE was mineralized to14CO2. Molecular phylogenetic analyses of these sediments indicated the enrichment of species closely related to a known MTBE-degrading bacterium, strain PM1. At only one site, the presence of water-soluble gasoline components significantly inhibited MTBE degradation and led to a more pronounced accumulation of the metabolite tert-butyl alcohol. Overall, these results suggest that the effects of oxygen and water-soluble gasoline components on in situ MTBE degradation will vary from site to site and that phylogenetic analysis may be a promising predictor of MTBE biodegradation potential.

scholarly journals Biodegradation of Methyl tert-Butyl Ether by a Pure Bacterial Culture

2001 ◽  
Vol 67 (12) ◽  
pp. 5601-5607 ◽  
Author(s):  
Paul B. Hatzinger ◽  
Kevin McClay ◽  
Simon Vainberg ◽  
Marina Tugusheva ◽  
Charles W. Condee ◽  
...  
Keyword(s):  
Bacterial Culture ◽  
Butyl Alcohol ◽  
The Other ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Pure Bacterial Culture ◽  
Degradation Activity ◽  
Type Strains ◽  
Mtbe Degradation ◽  
Allyl Thiourea

ABSTRACT Biodegradation of methyl tert-butyl ether (MTBE) by the hydrogen-oxidizing bacterium Hydrogenophaga flavaENV735 was evaluated. ENV735 grew slowly on MTBE ortert-butyl alcohol (TBA) as sole sources of carbon and energy, but growth on these substrates was greatly enhanced by the addition of a small amount of yeast extract. The addition of H2 did not enhance or diminish MTBE degradation by the strain, and MTBE was only poorly degraded or not degraded by type strains of Hydrogenophaga or hydrogen-oxidizing enrichment cultures, respectively. MTBE degradation activity was constitutively expressed in ENV735 and was not greatly affected by formaldehyde, carbon monoxide, allyl thiourea, or acetylene. MTBE degradation was inhibited by 1-amino benzotriazole and butadiene monoepoxide. TBA degradation was inducible by TBA and was inhibited by formaldehyde at concentrations of >0.24 mM and by acetylene but not by the other inhibitors tested. These results demonstrate that separate, independently regulated genes encode MTBE and TBA metabolism in ENV735.

scholarly journals Naturally Occurring Bacteria Similar to the Methyl tert-Butyl Ether (MTBE)-Degrading Strain PM1 Are Present in MTBE-Contaminated Groundwater

2003 ◽  
Vol 69 (5) ◽  
pp. 2616-2623 ◽  
Author(s):  
Krassimira Hristova ◽  
Binyam Gebreyesus ◽  
Douglas Mackay ◽  
Kate M. Scow
Keyword(s):  
Dna Sequences ◽  
Field Studies ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Naturally Occurring ◽  
Degrading Bacteria ◽  
Pure Cultures ◽  
Air Force Base ◽  
Mtbe Degradation

ABSTRACT Methyl tert-butyl ether (MTBE) is a widespread groundwater contaminant that does not respond well to conventional treatment technologies. Growing evidence indicates that microbial communities indigenous to groundwater can degrade MTBE under aerobic and anaerobic conditions. Although pure cultures of microorganisms able to degrade or cometabolize MTBE have been reported, to date the specific organisms responsible for MTBE degradation in various field studies have not be identified. We report that DNA sequences almost identical (99% homology) to those of strain PM1, originally isolated from a biofilter in southern California, are naturally occurring in an MTBE-polluted aquifer in Vandenberg Air Force Base (VAFB), Lompoc, California. Cell densities of native PM1 (measured by TaqMan quantitative PCR) in VAFB groundwater samples ranged from below the detection limit (in anaerobic sites) to 103 to 104 cells/ml (in oxygen-amended sites). In groundwater from anaerobic or aerobic sites incubated in microcosms spiked with 10 μg of MTBE/liter, densities of native PM1 increased to approximately 105 cells/ml. Native PM1 densities also increased during incubation of VAFB sediments during MTBE degradation. In controlled field plots amended with oxygen, artificially increasing the MTBE concentration was followed by an increase in the in situ native PM1 cell density. This is the first reported relationship between in situ MTBE biodegradation and densities of MTBE-degrading bacteria by quantitative molecular methods.

scholarly journals Biodegradation of Ether Pollutants by Pseudonocardia sp. Strain ENV478

2006 ◽  
Vol 72 (8) ◽  
pp. 5218-5224 ◽  
Author(s):  
Simon Vainberg ◽  
Kevin McClay ◽  
Hisako Masuda ◽  
Duane Root ◽  
Charles Condee ◽  
...  
Keyword(s):  
Yeast Extract ◽  
Degradation Product ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Butyl Alcohol ◽  
Butyl Ether ◽  
Degradation Rates ◽  
Degrading Bacteria ◽  
Contaminated Aquifers ◽  
Mtbe Degradation

ABSTRACT A bacterium designated Pseudonocardia sp. strain ENV478 was isolated by enrichment culturing on tetrahydrofuran (THF) and was screened to determine its ability to degrade a range of ether pollutants. After growth on THF, strain ENV478 degraded THF (63 mg/h/g total suspended solids [TSS]), 1,4-dioxane (21 mg/h/g TSS), 1,3-dioxolane (19 mg/h/g TSS), bis-2-chloroethylether (BCEE) (12 mg/h/g TSS), and methyl tert-butyl ether (MTBE) (9.1 mg/h/g TSS). Although the highest rates of 1,4-dioxane degradation occurred after growth on THF, strain ENV478 also degraded 1,4-dioxane after growth on sucrose, lactate, yeast extract, 2-propanol, and propane, indicating that there was some level of constitutive degradative activity. The BCEE degradation rates were about threefold higher after growth on propane (32 mg/h/g TSS) than after growth on THF, and MTBE degradation resulted in accumulation of tert-butyl alcohol. Degradation of 1,4-dioxane resulted in accumulation of 2-hydroxyethoxyacetic acid (2HEAA). Despite its inability to grow on 1,4-dioxane, strain ENV478 degraded this compound for >80 days in aquifer microcosms. Our results suggest that the inability of strain ENV478 and possibly other THF-degrading bacteria to grow on 1,4-dioxane is related to their inability to efficiently metabolize the 1,4-dioxane degradation product 2HEAA but that strain ENV478 may nonetheless be useful as a biocatalyst for remediating 1,4-dioxane-contaminated aquifers.

scholarly journals Infection Dynamics of Coexisting Beta- and Gammaproteobacteria in the Nested Endosymbiotic System of Mealybugs

2008 ◽  
Vol 74 (13) ◽  
pp. 4175-4184 ◽  
Author(s):  
Marie Kono ◽  
Ryuichi Koga ◽  
Masakazu Shimada ◽  
Takema Fukatsu
Keyword(s):  
Population Dynamics ◽  
Phylogenetic Analyses ◽  
Reproductive Activity ◽  
Adult Males ◽  
Female Development ◽  
Male Development ◽  
Infection Dynamics ◽  
Molecular Phylogenetic ◽  
Pseudococcus Comstocki

ABSTRACT We investigated the infection dynamics of endosymbiotic bacteria in the developmental course of the mealybugs Planococcus kraunhiae and Pseudococcus comstocki. Molecular phylogenetic analyses identified a betaproteobacterium and a gammaproteobacterium from each of the mealybug species. The former bacterium was related to the β-endosymbionts of other mealybugs, i.e., “Candidatus Tremblaya princeps,” and formed a compact clade in the Betaproteobacteria. Meanwhile, the latter bacterium was related to the γ-endosymbionts of other mealybugs but belonged to distinct clades in the Gammaproteobacteria. Whole-mount in situ hybridization confirmed the peculiar nested formation in the endosymbiotic system of the mealybugs: the β-endosymbiont cells were present in the cytoplasm of the bacteriocytes, and the γ-endosymbiont cells were located in the β-endosymbiont cells. In nymphal and female development, a large oval bacteriome consisting of a number of bacteriocytes was present in the abdomen, wherein the endosymbionts were harbored. In male development, strikingly, the bacteriome progressively degenerated in prepupae and pupae and became almost unrecognizable in adult males. In the degeneration process, the γ-endosymbionts disappeared more rapidly than the β-endosymbionts did. Quantitative PCR analyses revealed that (i) the population dynamics of the endosymbionts in female development reflected the reproductive activity of the insects, (ii) the population dynamics of the endosymbionts were strikingly different between female development and male development, (iii) the endosymbiont populations drastically decreased in male development, and (iv) the γ-endosymbiont populations decreased more rapidly than the β-endosymbiont populations in male development. Possible mechanisms underlying the uncoupled regulation of the β- and γ-endosymbiont populations are discussed in relation to the establishment and evolution of this unique prokaryote-prokaryote endosymbiotic system.

scholarly journals The metagenomics of biosilicification: causes and effects

2008 ◽  
Vol 72 (1) ◽  
pp. 221-225 ◽  
Author(s):  
L. G. Benning ◽  
D. J. Tobler
Keyword(s):  
Microbial Diversity ◽  
Bacterial Communities ◽  
Phylogenetic Diversity ◽  
Hot Springs ◽  
Phylogenetic Analyses ◽  
Geochemical Parameters ◽  
Molecular Phylogenetic ◽  
Geothermal Environments

AbstractIn order to determine the links between geochemical parameters controlling the formation of silica sinter in hot springs and their associated microbial diversity, a detailed characterisation of the waters and ofin situ-grown silica sinters was combined with molecular phylogenetic analyses of the bacterial communities in Icelandic geothermal environments. At all but one site, the microorganisms clearly affected, and in part controlled, the formation of the macroscopic textures and structures of silica sinter edifices. In addition, the class and genera level phylogenetic diversity and distribution appeared to be closely linked to variations in temperature, salinity and pH regimes.

Tripartite organization of the ancestral chordate brain and the antiquity of placodes: insights from ascidian Pax-2/5/8, Hox and Otx genes

Development ◽  
1998 ◽  
Vol 125 (6) ◽  
pp. 1113-1122 ◽  
Author(s):  
H. Wada ◽  
H. Saiga ◽  
N. Satoh ◽  
P.W. Holland
Keyword(s):  
Neural Tube ◽  
Hox Genes ◽  
Phylogenetic Analyses ◽  
Nervous Systems ◽  
Vertebrate Brain ◽  
Molecular Phylogenetic ◽  
Central Nervous Systems ◽  
Single Precursor ◽  
In Situ Hybridizations

Ascidians and vertebrates belong to the Phylum Chordata and both have dorsal tubular central nervous systems. The structure of the ascidian neural tube is extremely simple, containing less than 400 cells, among which less than 100 cells are neurons. Recent studies suggest that, despite its simple organization, the mechanisms patterning the ascidian neural tube are similar to those of the more complex vertebrate brain. Identification of homologous regions between vertebrate and ascidian nervous systems, however, remains to be resolved. Here we report the expression of HrPax-258 gene: an ascidian homologue of vertebrate Pax-2, Pax-5 and Pax-8 genes. Molecular phylogenetic analyses indicate that HrPax-258 is descendant from a single precursor gene that gave rise to the three vertebrate genes. The expression pattern of HrPax-258 suggests that this subfamily of Pax genes has conserved roles in regional specification of the brain. Comparison with expression of ascidian Otx (Hroth) and a Hox gene (HrHox1) by double-staining in situ hybridizations indicate that the ascidian brain region can be subdivided into three regions; the anterior region marked by Hroth probably homologous to the vertebrate forebrain and midbrain, the middle region marked by HrPax-258 probably homologous to the vertebrate anterior hindbrain (and maybe also midbrain) and the posterior region marked by Hox genes which is homologous to the vertebrate hindbrain and spinal cord. Later expression of HrPax-258 in atrial primordia implies that basal chordates such as ascidians have already acquired a sensory organ that develops from epidermal thickenings (placodes) and expresses HrPax-258; we suggest it is homologous to the vertebrate ear. Therefore, placodes are not likely to be a newly acquired feature in vertebrates, but may have already been possessed by the earliest chordates.

scholarly journals Comparative Transcriptome Analysis of Methylibium petroleiphilum PM1 Exposed to the Fuel Oxygenates Methyl tert-Butyl Ether and Ethanol

2007 ◽  
Vol 73 (22) ◽  
pp. 7347-7357 ◽  
Author(s):  
Krassimira R. Hristova ◽  
Radomir Schmidt ◽  
Anu Y. Chakicherla ◽  
Tina C. Legler ◽  
Janice Wu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Carbon Sources ◽  
Degradation Pathway ◽  
Butyl Alcohol ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Fuel Oxygenates ◽  
Degrading Bacteria ◽  
Pollutant Mixtures ◽  
Mtbe Degradation

ABSTRACT High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.

Two Intracellular Symbiotic Bacteria from the Mulberry Psyllid Anomoneura mori (Insecta, Homoptera)

1998 ◽  
Vol 64 (10) ◽  
pp. 3599-3606 ◽  
Author(s):  
Takema Fukatsu ◽  
Naruo Nikoh
Keyword(s):  
In Situ Hybridization ◽  
16S Rdna ◽  
Phylogenetic Analyses ◽  
Symbiotic Bacteria ◽  
Polymorphism Analysis ◽  
16S Rdna Sequence ◽  
Rdna Sequences ◽  
16S Rdna Sequences ◽  
Molecular Phylogenetic

ABSTRACT We characterized the intracellular symbiotic bacteria of the mulberry psyllid Anomoneura mori by performing a molecular phylogenetic analysis combined with in situ hybridization. In its abdomen, the psyllid has a large, yellow, bilobed mycetome (or bacteriome) which consists of many round uninucleated mycetocytes (or bacteriocytes) enclosing syncytial tissue. The mycetocytes and syncytium harbor specific intracellular bacteria, the X-symbionts and Y-symbionts, respectively. Almost the entire length of the bacterial 16S ribosomal DNA (rDNA) was amplified and cloned from the whole DNA ofA. mori, and two clones, the A-type and B-type clones, were identified by restriction fragment length polymorphism analysis. In situ hybridization with specific oligonucleotide probes demonstrated that the A-type and B-type 16S rDNAs were derived from the X-symbionts and Y-symbionts, respectively. Molecular phylogenetic analyses of the 16S rDNA sequences showed that these symbionts belong to distinct lineages in the γ subdivision of the Proteobacteria. No 16S rDNA sequences in the databases were closely related to the 16S rDNA sequences of the X- and Y-symbionts. However, the sequences that were relatively closely related to them were the sequences of endosymbionts of other insects. The nucleotide compositions of the 16S rDNAs of the X- and Y-symbionts were highly AT biased, and the sequence of the X-symbiont was the most AT-rich bacterial 16S rDNA sequence reported so far.

scholarly journals Kinetics of Methyl t-Butyl Ether Cometabolism at Low Concentrations by Pure Cultures of Butane-Degrading Bacteria

2001 ◽  
Vol 67 (5) ◽  
pp. 2197-2201 ◽  
Author(s):  
Catherine Y. Liu ◽  
Gerald E. Speitel ◽  
George Georgiou
Keyword(s):  
Negative Impact ◽  
Streptomyces Griseus ◽  
Butyl Alcohol ◽  
Utilization Rate ◽  
Butyl Ether ◽  
Low Concentrations ◽  
Degrading Bacteria ◽  
Tryptose Phosphate Broth ◽  
Pure Cultures ◽  
Mtbe Degradation

ABSTRACT Butane-oxidizing Arthrobacter (ATCC 27778) bacteria were shown to degrade low concentrations of methylt-butyl ether (MTBE; range, 100 to 800 μg/liter) with an apparent half-saturation concentration (K s ) of 2.14 mg/liter and a maximum substrate utilization rate (kc) of 0.43 mg/mg of total suspended solids per day. Arthrobacter bacteria demonstrated MTBE degradation activity when grown on butane but not when grown on glucose, butanol, or tryptose phosphate broth. The presence of butane, tert-butyl alcohol, or acetylene had a negative impact on the MTBE degradation rate. NeitherMethylosinus trichosporium OB3b nor Streptomyces griseus was able to cometabolize MTBE.

Functional Poly(p-Xylylene)s via Chemical Reduction of Poly(p-Phenylene Vinylene)s

2019 ◽  
Author(s):  
Ain Uddin ◽  
Weifan Sang ◽  
Yong Gao ◽  
Kyle Plunkett
Keyword(s):  
Film Formation ◽  
Chemical Reduction ◽  
Water Soluble ◽  
Phenylene Vinylene ◽  
Polymer Modification ◽  
Polymer Backbone ◽  
Crosslinking Process ◽  
Conducting Membranes ◽  
In Situ Crosslinking

The synthesis of poly(p-xylylene)s (PPXs) with sidechains containing alkyl bromide functionality, and their post-polymer modification, is described. The PPXs were prepared by a diimide hydrogenation of poly(p-phenylene vinylene)s (PPVs) that were originally synthesized by a Gilch polymerization. The polymer backbone reduction was carried out with hydrazine hydrate in toluene at 80 °C to provide polymers with the sidechain-containing bromide functionality intact. To demonstrate post-polymer modification of the sidechains, the resulting PPX polymers were modified with trimethylamine to form tetraalkylammonium ion functionality and were evaluated as anion conducting membranes. While PPX homopolymers containing tetralkylammonium ions were completely water soluble and not able to form valuable films, PPX copolymers containing mixed tetraalkylammonium ions and hydrophobic chains were capable of film formation and alkaline stability. In addition, an in situ crosslinking process that used N,N,N',N'-tetramethyl-1,6-hexanediamine during the tetraalkylammonium formation of brominated PPX polymers was also evaluated and gave reasonable films with conductivities of ~10 mS-cm-1.

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