Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 27
Filter
1.
J Autism Dev Disord ; 52(12): 5308-5320, 2022 Dec.
Article in English | MEDLINE | ID: mdl-34981308

ABSTRACT

This paper describes a process to define a comprehensive list of exemplars for seven core Diagnostic and Statistical Manual (DSM) diagnostic criteria for autism spectrum disorder (ASD), and report on interrater reliability in applying these exemplars to determine ASD case classification. Clinicians completed an iterative process to map specific exemplars from the CDC Autism and Developmental Disabilities Monitoring (ADDM) Network criteria for ASD surveillance, DSM-5 text, and diagnostic assessments to each of the core DSM-5 ASD criteria. Clinicians applied the diagnostic exemplars to child behavioral descriptions in existing evaluation records to establish initial reliability standards and then for blinded clinician review in one site (phase 1) and for two ADDM Network surveillance years (phase 2). Interrater reliability for each of the DSM-5 diagnostic categories and overall ASD classification was high (defined as very good .60-.79 to excellent ≥ .80 Kappa values) across sex, race/ethnicity, and cognitive levels for both phases. Classification of DSM-5 ASD by mapping specific exemplars from evaluation records by a diverse group of clinician raters is feasible and reliable. This framework provides confidence in the consistency of prevalence classifications of ASD and may be further applied to improve consistency of ASD diagnoses in clinical settings.


Subject(s)
Autism Spectrum Disorder , Diagnostic and Statistical Manual of Mental Disorders , Patient Selection , Child , Humans , Autism Spectrum Disorder/diagnosis , Autism Spectrum Disorder/epidemiology , Population Surveillance , Prevalence , Reproducibility of Results
3.
Arch Pediatr ; 19(1): 42-6, 2012 Jan.
Article in French | MEDLINE | ID: mdl-22115729

ABSTRACT

We report on 2 cases associating retinal (RH) and cerebral hemorrhages (CH), which first suggested the diagnosis of shaken baby syndrome (SBS). After an etiologic search, the diagnosis was corrected: the first case was a late hemorrhagic disease of the newborn and the second case hemophilia A. RH is a major feature of SBS, although not pathognomonic. There is no specific RH of SBS but they usually affect the posterior retinal pole. Typically, RHs of SBS are present in both eyes, although unilateral RHs do not exclude the diagnosis of SBS. The relationship between RH and CH has been reported in SBS but also in other diseases. Thus, one must search for hemostasis abnormalities, even though the clinical presentation suggests SBS. Ignoring SBS as well as coming to the conclusion of SBS too quickly should be avoided. Diagnostic difficulties may be related to the number of physicians involved and their interpretation of the facts. These 2 cases underline the need for working as a team that includes hematologists able to interpret coagulation parameters.


Subject(s)
Cerebral Hemorrhage/etiology , Hematoma, Subdural/etiology , Hemophilia A/complications , Retinal Hemorrhage/etiology , Shaken Baby Syndrome/complications , Vitamin K Deficiency Bleeding/complications , Antifibrinolytic Agents/administration & dosage , Cerebral Hemorrhage/diagnosis , Cerebral Hemorrhage/surgery , Coagulants/administration & dosage , Consanguinity , Diagnosis, Differential , Factor VIII/administration & dosage , Fatal Outcome , Hematoma, Subdural/diagnosis , Hematoma, Subdural/surgery , Hemophilia A/diagnosis , Hemophilia A/drug therapy , Humans , Infant , Infant, Newborn , Male , Retinal Hemorrhage/diagnosis , Retinal Hemorrhage/surgery , Risk Factors , Shaken Baby Syndrome/diagnosis , Vitamin K 1/administration & dosage , Vitamin K Deficiency Bleeding/diagnosis , Vitamin K Deficiency Bleeding/drug therapy
5.
J Biotechnol ; 156(3): 163-72, 2011 Dec 10.
Article in English | MEDLINE | ID: mdl-21906639

ABSTRACT

Pseudomonas putida KT2440-JD1 was derived from P. putida KT2440 after N-methyl-N'-nitro-N-nitrosoguanidine (NTG)-mutagenesis and exposure to 3-fluorobenzoate (3-FB). The mutant was no longer able to grow using benzoate as a sole carbon source, but co-metabolized benzoate to cis, cis-muconate during growth on glucose, which accumulated in the growth medium. The specific production rate (q(pm)) was 0.18±0.03 g cis, cis-muconate/(g(DCW) h) in continuous cultures, and increased to 1.4 g cis, cis-muconate/(g(DCW) h) during wash-out cultivation. Transcriptome analysis showed that the cat operon was not induced in P. putida KT2440-JD1 in the presence of 5mM benzoate, due to a point mutation in the highly conserved DNA binding domain of the transcriptional regulator (catR) of the cat operon. The ben operon was highly expressed in the presence of benzoate in the mutant and its parental strain. This operon contains PP_3166 (catA2), which was shown to be a second catechol 1,2-dioxygenase besides catA. P. putida KT2440-JD1 is the first cis, cis-muconate-accumulating mutant that was characterized at the genetic level. The specific production rate achieved is at least eight times higher than those reported for other cis, cis-muconate-producing strains.


Subject(s)
Bacterial Proteins/genetics , DNA-Binding Proteins/genetics , Gene Expression Regulation, Bacterial , Pseudomonas putida , Sorbic Acid/analogs & derivatives , Transcription Factors/genetics , Benzoates/metabolism , Benzoates/toxicity , Biotechnology/methods , Mutation/drug effects , Operon/genetics , Pseudomonas putida/genetics , Pseudomonas putida/metabolism , Regulatory Elements, Transcriptional , Sorbic Acid/metabolism , Up-Regulation
7.
Biotechnol Bioeng ; 108(6): 1298-306, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21328320

ABSTRACT

A limited life cycle assessment (LCA) was performed on a combined biological and chemical process for the production of adipic acid, which was compared to the traditional petrochemical process. The LCA comprises the biological conversion of the aromatic feedstocks benzoic acid, impure aromatics, toluene, or phenol from lignin to cis, cis-muconic acid, which is subsequently converted to adipic acid through hydrogenation. Apart from the impact of usage of petrochemical and biomass-based feedstocks, the environmental impact of the final concentration of cis, cis-muconic acid in the fermentation broth was studied using 1.85% and 4.26% cis, cis-muconic acid. The LCA focused on the cumulative energy demand (CED), cumulative exergy demand (CExD), and the CO(2) equivalent (CO(2) eq) emission, with CO(2) and N(2) O measured separately. The highest calculated reduction potential of CED and CExD were achieved using phenol, which reduced the CED by 29% and 57% with 1.85% and 4.26% cis, cis-muconic acid, respectively. A decrease in the CO(2) eq emission was especially achieved when the N(2) O emission in the combined biological and chemical process was restricted. At 4.26% cis, cis-muconic acid, the different carbon backbone feedstocks contributed to an optimized reduction of CO(2) eq emissions ranging from 14.0 to 17.4 ton CO(2) eq/ton adipic acid. The bulk of the bioprocessing energy intensity is attributed to the hydrogenation reactor, which has a high environmental impact and a direct relationship with the product concentration in the broth.


Subject(s)
Adipates/metabolism , Benzoic Acid/metabolism , Biotechnology/methods , Caprolactam/analogs & derivatives , Polymers/metabolism , Pseudomonas putida/metabolism , Biomass , Caprolactam/metabolism , Environment , Fossil Fuels
9.
Cephalalgia ; 29(11): 1197-201, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19811504

ABSTRACT

The prevalence and characterization of premonitory symptoms have not been rigorously studied in children and adolescents. Using a questionnaire, we retrospectively studied the prevalence of 15 predefined premonitory symptoms in a clinic-based population. In 103 children and adolescents fulfilling the International Classification of Headache Disorders, 2nd edn criteria for paediatric migraine, at least one premonitory symptom was reported by 69 (67%). The most frequently reported premonitory symptoms were face changes, fatigue and irritability. The mean number of premonitory symptoms reported per subject was 1.8 (median 2.2). Age, migraine subtype (with or without aura) and mean attack frequency per month had no effect on the mean number of premonitory symptoms reported per subject. In conclusion, premonitory symptoms are frequently reported by children and adolescents with migraine. Face changes seem to be a premonitory symptom peculiar to paediatric migraine.


Subject(s)
Migraine Disorders/epidemiology , Adolescent , Child , Child, Preschool , Fatigue/epidemiology , Female , Humans , Hyperacusis/epidemiology , Hyperkinesis/epidemiology , Male , Mood Disorders/epidemiology , Nausea/epidemiology , Neck Pain/epidemiology , Photophobia/epidemiology , Prevalence , Sleep Wake Disorders/epidemiology , Surveys and Questionnaires , Yawning
10.
Arch Pediatr ; 14(12): 1435-8, 2007 Dec.
Article in French | MEDLINE | ID: mdl-17988842

ABSTRACT

Stevens-Johnson syndrome is an acute, self-limiting disease of the skin and mucous membranes. Erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis are all part of a single spectrum illness. We report severe erythema multiform in 4 children aged from 6 to 15 years old. Erythema was mostly related to mycoplasma pneumoniae infection (3/4) and 1 case was attributed to drugs. Two children developed severe sequelae (obliterans bronchiolitis). No patient had recurrent disease. The early use of steroids is still debated, but in our experience it seems to benefit overall. A long term follow-up is necessary with the study of pulmonary function tests and chest X-rays ophtalmologic and dermatologic examination.


Subject(s)
Stevens-Johnson Syndrome/diagnosis , Adolescent , Child , Diagnosis, Differential , Female , Follow-Up Studies , Humans , Male , Pneumonia, Mycoplasma/complications , Radiography, Thoracic , Stevens-Johnson Syndrome/diagnostic imaging
11.
Appl Microbiol Biotechnol ; 74(6): 1358-67, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17216445

ABSTRACT

NMR analysis of (13)C-labelling patterns showed that the Embden-Meyerhof (EM) pathway is the main route for glycolysis in the extreme thermophile Caldicellulosiruptor saccharolyticus. Glucose fermentation via the EM pathway to acetate results in a theoretical yield of 4 mol of hydrogen and 2 mol of acetate per mole of glucose. Previously, approximately 70% of the theoretical maximum hydrogen yield has been reached in batch fermentations. In this study, hydrogen and acetate yields have been determined at different dilution rates during continuous cultivation. The yields were dependent on the growth rate. The highest hydrogen yields of 82 to 90% of theoretical maximum (3.3 to 3.6 mol H(2) per mol glucose) were obtained at low growth rates when a relatively larger part of the consumed glucose is used for maintenance. The hydrogen productivity showed the opposite effect. Both the specific and the volumetric hydrogen production rates were highest at the higher growth rates, reaching values of respectively 30 mmol g(-1) h(-1) and 20 mmol l(-1) h(-1). An industrial process for biohydrogen production will require a bioreactor design, which enables an optimal mix of high productivity and high yield.


Subject(s)
Bacteria, Anaerobic/metabolism , Glycolysis , Hydrogen/metabolism , Acetates/chemistry , Acetates/metabolism , Carbon Isotopes , Fermentation , Glucose/metabolism , Hydrogen/chemistry , Magnetic Resonance Spectroscopy , Temperature
12.
Vet Microbiol ; 109(3-4): 229-43, 2005 Aug 30.
Article in English | MEDLINE | ID: mdl-15982833

ABSTRACT

There is no ring test for quality assessment available in Europe for diagnostics and antimicrobial susceptibility testing of the fastidious, anaerobic bacteria of the genus Brachyspira. Therefore, an international ring test for Brachyspira spp. was performed once a year during 2002-2004. Two sets of coded samples were prepared and distributed on each occasion. One set comprised six swabs dipped in pig faeces spiked with Brachyspira spp. intended for diagnostics. The other set comprised two pure strains intended only for susceptibility testing. All methods used were in-house methods. The species used were Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira innocens, Brachyspira murdochii and Brachyspira intermedia. In most cases, the correct Brachyspira spp. were detected. However, the results showed that Brachyspira spp. could be difficult to identify, especially if two Brachyspira spp. were mixed or if the concentration of Brachyspira in faeces was low. Additionally, some laboratories reported Brachyspira growth in control samples that were not seeded with any spirochaetes. The lowest detection level was 10(2) bacteria/ml faeces for both B. hyodysenteriae and B. pilosicoli. The susceptibility tests performed showed that disc diffusion was not recommendable for Brachyspira spp. Extended antimicrobial dilution series gave most congruent results. The diversity of the results highlights the importance of ring tests for a high quality of diagnostics and antimicrobial susceptibility tests for Brachyspira spp. This is the first ring test described for Brachyspira spp.


Subject(s)
Anti-Bacterial Agents/pharmacology , Spirochaetaceae/drug effects , Spirochaetales Infections/veterinary , Swine Diseases/microbiology , Animals , Bacterial Typing Techniques , Europe , Feces/microbiology , Microbial Sensitivity Tests , Spirochaetaceae/isolation & purification , Spirochaetales Infections/diagnosis , Spirochaetales Infections/microbiology , Swine , Swine Diseases/diagnosis
13.
Resuscitation ; 57(2): 153-9, 2003 May.
Article in English | MEDLINE | ID: mdl-12745183

ABSTRACT

BACKGROUND: In some patients with ventricular fibrillation (VF) there may be a better chance of successful defibrillation after a period of chest compression and ventilation before the defibrillation attempt. It is therefore important to know whether a defibrillation attempt will be successful. The predictive power of a model developed by 'genetic' programming (GP) to predict defibrillation success was studied. METHODS AND RESULTS: 203 defibrillations were administered in 47 patients with out-of-hospital cardiac arrest due to a cardiac cause. Maximal amplitude, a total energy of power spectral density, and the Hurst exponent of the VF electrocardiogram (ECG) signal were included in the model developed by GP. Positive and negative likelihood ratios of the model for testing data were 35.5 and 0.00, respectively. Using a model developed by GP on the complete database, 120 of the 124 unsuccessful defibrillations would have been avoided, whereas all of the 79 successful defibrillations would have been administered. CONCLUSION: The VF ECG contains information predictive of defibrillation success. The model developed by GP, including data from the time-domain, frequency-domain and nonlinear dynamics, could reduce the incidence of unsuccessful defibrillations.


Subject(s)
Electric Countershock , Heart Arrest/therapy , Software , Ventricular Fibrillation/therapy , Aged , Cardiopulmonary Resuscitation/methods , Electrocardiography , Female , Genetics , Heart Arrest/complications , Humans , Male , Middle Aged , Models, Theoretical , Prognosis , Ventricular Fibrillation/complications
14.
Pediatrics ; 108(5): 1155-61, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11694696

ABSTRACT

OBJECTIVE: This study determined the prevalence of autism for a defined community, Brick Township, New Jersey, using current diagnostic and epidemiologic methods. METHODS: The target population was children who were 3 to 10 years of age in 1998, who were residents of Brick Township at any point during that year, and who had an autism spectrum disorder. Autism spectrum disorder was defined as autistic disorder, pervasive developmental disorder-not otherwise specified (PDD-NOS), and Asperger disorder. The study used 4 sources for active case finding: special education records, records from local clinicians providing diagnosis or treatment for developmental or behavioral disabilities, lists of children from community parent groups, and families who volunteered for participation in the study in response to media attention. The autism diagnosis was verified (or ruled out) for 71% of the children through clinical assessment. The assessment included medical and developmental history, physical and neurologic evaluation, assessment of intellectual and behavioral functioning, and administration of the Autism Diagnostic Observation Schedule-Generic. RESULTS: The prevalence of all autism spectrum disorders combined was 6.7 cases per 1000 children. The prevalence for children whose condition met full diagnostic criteria for autistic disorder was 4.0 cases per 1000 children, and the prevalence for PDD-NOS and Asperger disorder was 2.7 cases per 1000 children. Characteristics of children with autism in this study were similar to those in previous studies of autism. CONCLUSIONS: The prevalence of autism in Brick Township seems to be higher than that in other studies, particularly studies conducted in the United States, but within the range of a few recent studies in smaller populations that used more thorough case-finding methods.


Subject(s)
Autistic Disorder/epidemiology , Anthropometry , Autistic Disorder/diagnosis , Autistic Disorder/physiopathology , Child , Child, Preschool , Female , Humans , Intelligence , Male , New Jersey/epidemiology , Prevalence , Severity of Illness Index , Sex Distribution
15.
Appl Microbiol Biotechnol ; 56(1-2): 101-7, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11499915

ABSTRACT

Pseudomonas putida GS1 is able to convert limonene to perillic acid (up to 64 mM,(11 g/l) when the bacteria is cultivated in fed-batch culture with non-limiting amounts of glycerol. ammonium, and limonene. P. putida GS1 can use p-cymene as a single source of carbon and energy, and the enzymes that are responsible for the conversion of limonene to perillic acid belong to the degradation pathway of p-cymene. The p-cymene pathway of P putida GS1 is very similar, if not identical, to the cym pathway of P. putida F1. The latter strain, and a recombinant Escherichia coli strain that carried the genes of the cym pathway of P. putida Fl, also converted limonene to perillic acid. However, the final concentrations that were obtained in batch cultures with these two strains were lower than those obtained with P. putida GS1.


Subject(s)
Monoterpenes , Pseudomonas putida/metabolism , Terpenes/metabolism , Bioreactors , Cyclohexenes , Cymenes , Limonene , Oxidation-Reduction
16.
Curr Opin Microbiol ; 3(3): 257-62, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10851165

ABSTRACT

The reactivity and toxicity of metabolic intermediates that are generated by initial biotransformation reactions can be a major limiting factor for biodegradation of halogenated organic compounds. Recent work on the conversion of haloalkanes, chloroaromatics and chloroethenes indicates that microorganisms may become less sensitive to toxic effects either by using novel pathways that circumvent the generation of reactive intermediates or by producing modified enzymes that decrease the toxicity of such compounds.


Subject(s)
Bacteria, Anaerobic/enzymology , Halogens/metabolism , Industrial Microbiology/methods , Industrial Waste , Bacterial Proteins/metabolism , Enzymes/metabolism , Halogens/chemistry
17.
J Bacteriol ; 181(4): 1309-18, 1999 Feb.
Article in English | MEDLINE | ID: mdl-9973359

ABSTRACT

Pseudomonas putida GJ31 contains an unusual catechol 2,3-dioxygenase that converts 3-chlorocatechol and 3-methylcatechol, which enables the organism to use both chloroaromatics and methylaromatics for growth. A 3.1-kb region of genomic DNA of strain GJ31 containing the gene for this chlorocatechol 2,3-dioxygenase (cbzE) was cloned and sequenced. The cbzE gene appeared to be plasmid localized and was found in a region that also harbors genes encoding a transposase, a ferredoxin that was homologous to XylT, an open reading frame with similarity to a protein of a meta-cleavage pathway with unknown function, and a 2-hydroxymuconic semialdehyde dehydrogenase. CbzE was most similar to catechol 2,3-dioxygenases of the 2.C subfamily of type 1 extradiol dioxygenases (L. D. Eltis and J. T. Bolin, J. Bacteriol. 178:5930-5937, 1996). The substrate range and turnover capacity with 3-chlorocatechol were determined for CbzE and four related catechol 2,3-dioxygenases. The results showed that CbzE was the only enzyme that could productively convert 3-chlorocatechol. Besides, CbzE was less susceptible to inactivation by methylated catechols. Hybrid enzymes that were made of CzbE and the catechol 2, 3-dioxygenase of P. putida UCC2 (TdnC) showed that the resistance of CbzE to suicide inactivation and its substrate specificity were mainly determined by the C-terminal region of the protein.


Subject(s)
Catechols/metabolism , Dioxygenases , Oxygenases/genetics , Oxygenases/metabolism , Pseudomonas putida/genetics , Amino Acid Sequence , Catechol 2,3-Dioxygenase , Cloning, Molecular , Genes, Bacterial , Molecular Sequence Data , Plasmids , Pseudomonas putida/enzymology , Recombinant Fusion Proteins , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Substrate Specificity
18.
J Pediatr ; 132(3 Pt 1): 500-4, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9544908

ABSTRACT

OBJECTIVES: The objectives of this study were (1) to show prediagnostic abnormalities in social and communicative behaviors on home videos of children who later received a diagnosis of one of the pervasive developmental disorders (PDD) and (2) to demonstrate that prediagnostic abnormalities in social and communicative behaviors for children with PDD not otherwise specified will be less prominent than those in children with autistic disorder but still distinguishable from those of typically developing peers. STUDY DESIGN: Parents of children with PDD each submitted home videos of social events that were made when their child was between the ages of 12 and 30 months, before diagnosis. Two independent observers, unaware of the subjects' diagnoses or purpose of the study, scored the rates of specific anomalies in social and communicative behavior. Two additional observers scored the percentage of time the children were engaged socially or with objects. Data from the experimental group were compared with those of 25 age-matched children with no developmental disabilities. RESULTS: Significant differences were found between the rates of social engagement and 8 of the 25 specific behaviors of the children in whom PDD was later diagnosed and those of the typical children. The children later given the diagnosis of PDD not otherwise specified had mean frequencies of some social interactions and communicative skills that fell between those of children later given the diagnosis of autistic disorder and those of children with typical development. CONCLUSION: In our sample children in whom PDD was later diagnosed could be differentiated from their typically developing peers on the basis of specific anomalies noted in their social and communicative behaviors, especially joint attention. In our sample children with PDD not otherwise specified could have been further differentiated on the basis of the rates of social interaction. Careful assessment of social interaction and communicative behaviors may help to identify children with PDD before the age of 30 months.


Subject(s)
Child Development Disorders, Pervasive/diagnosis , Videotape Recording , Autistic Disorder/diagnosis , Child Development Disorders, Pervasive/classification , Child, Preschool , Communication , Female , Humans , Infant , Male , Social Behavior
19.
J Bacteriol ; 180(2): 296-302, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9440519

ABSTRACT

A purification procedure for a new kind of extradiol dioxygenase, termed chlorocatechol 2,3-dioxygenase, that converts 3-chlorocatechol productively was developed. Structural and kinetic properties of the enzyme, which is part of the degradative pathway used for growth of Pseudomonas putida GJ31 with chlorobenzene, were investigated. The enzyme has a subunit molecular mass of 33.4 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Estimation of the native Mr value under nondenaturating conditions by gel filtration gave a molecular mass of 135 +/- 10 kDa, indicating a homotetrameric enzyme structure (4 x 33.4 kDa). The pI of the enzyme was estimated to be 7.1 +/- 0.1. The N-terminal amino acid sequence (43 residues) of the enzyme was determined and exhibits 70 to 42% identity with other extradiol dioxygenases. Fe(II) seems to be a cofactor of the enzyme, as it is for other catechol 2,3-dioxygenases. In contrast to other extradiol dioxygenases, the enzyme exhibited great sensitivity to temperatures above 40 degrees C. The reactivity of this enzyme toward various substituted catechols, especially 3-chlorocatechol, was different from that observed for other catechol 2,3-dioxygenases. Stoichiometric displacement of chloride occurred from 3-chlorocatechol, leading to the production of 2-hydroxymuconate.


Subject(s)
Chlorobenzenes/metabolism , Dioxygenases , Oxygenases/metabolism , Pseudomonas putida/enzymology , Amino Acid Sequence , Biodegradation, Environmental , Electrophoresis, Polyacrylamide Gel , Hydrogen-Ion Concentration , Molecular Sequence Data , Oxygenases/antagonists & inhibitors , Oxygenases/isolation & purification , Substrate Specificity , Temperature
20.
Appl Environ Microbiol ; 64(1): 208-15, 1998 Jan.
Article in English | MEDLINE | ID: mdl-16349481

ABSTRACT

The influence of trichloroethylene (TCE) on a mixed culture of four different toluene-degrading bacterial strains (Pseudomonas putida mt-2, P. putida F1, P. putida GJ31, and Burkholderia cepacia G4) was studied with a fed-batch culture. The strains were competing for toluene, which was added at a very low rate (31 nmol mg of cells [dry weight] h). All four strains were maintained in the mixed culture at comparable numbers when TCE was absent. After the start of the addition of TCE, the viabilities of B. cepacia G4 and P. putida F1 and GJ31 decreased 50- to 1,000-fold in 1 month. These bacteria can degrade TCE, although at considerably different rates. P. putida mt-2, which did not degrade TCE, became the dominant organism. Kinetic analysis showed that the presence of TCE caused up to a ninefold reduction in the affinity for toluene of the three disappearing strains, indicating that inhibition of toluene degradation by TCE occurred. While P. putida mt-2 took over the culture, mutants of this strain which could no longer grow on p-xylene arose. Most of them had less or no meta-cleavage activity and were able to grow on toluene with a higher growth rate. The results indicate that cometabolic degradation of TCE has a negative effect on the maintenance and competitive behavior of toluene-utilizing organisms that transform TCE.

SELECTION OF CITATIONS
SEARCH DETAIL
...