Prevalencia e incidencia de sobrepeso y obesidad en 2, 5 millones de niños y adolescentes en España / The prevalence and incidence rate of overweight and obesity among 2.5 million children and adolescents in Spain

Introducción y objetivos: Las tendencias de la obesidad infantil se están estancando en España, pero hay poca información sobre las diferencias por comunidad autónoma. Este estudio evaluó en 8 comunidades autónomas la prevalencia y la incidencia de sobrepeso y obesidad en niños y adolescentes entre 2005-2017. Métodos: Este estudio longitudinal utilizó las determinaciones de estatura y peso de 2,5 millones de niños de 2-17 años para calcular el sobrepeso y la obesidad según las guías de la OMS. Los datos proceden de 2 bases de datos de historias clínicas electrónicas: la Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria y el Sistema de Información para la Investigación en Atención Primaria. Se calcularon la prevalencia, la tasa de incidencia y las tendencias entre 2005-2017, y se estratificaron por edad, sexo y comunidad autónoma. Resultados: La prevalencia general de obesidad aumentó en niños y niñas desde los 2 años (0,8%; IC95%, 0,8-0,9% en ambos sexos) hasta alcanzar su punto máximo a los 7 años en las niñas (17,3%; IC95%, 17,1-17,5%) y a los 9 años en los niños (24,1%; IC95%, 23,9-24,3%). Las prevalencias de obesidad más altas y más bajas se observaron en Murcia y Navarra respectivamente. Las tendencias generales de la prevalencia de obesidad disminuyeron de 2005 a 2017 en todos los grupos de edad y sexo y en la mayoría de las comunidades autónomas. Las tasas de incidencia de obesidad más altas se encontraron en niños de 6-7 años (4,5 [4,5-4,5] y 3,5 [3,5-3,5] nuevos casos de obesidad cada 100 personas-año en niños y niñas respectivamente). Los niños tenían cifras de prevalencia e incidencia más altas que las niñas en todas las comunidades autónomas. Los valores de prevalencia e incidencia de sobrepeso/obesidad y sus tendencias fueron constantemente mayores que los de obesidad, aunque se observó un patrón similar según edad y sexo. Conclusiones: La prevalencia de sobrepeso y obesidad se redujo ligeramente en España (AU)

Introduction and objectives: Childhood obesity trends are plateauing in Spain, but limited information is available about how they differ by region. This study assessed childhood and adolescent the prevalence and incidence of overweight and obesity from 2005 to 2017 across 8 Spanish regions. Methods: This longitudinal study used height and weight measurements from 2.5 million children aged 2 to 17 years to calculate overweight and obesity, according to the World Health Organization (WHO) guidelines. Data were obtained from The Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria, and the Information System for Research in Primary Care. Prevalence and incidence rates and trends from 2005 to 2017 were calculated and stratified by age, sex, and region. Results: The overall obesity prevalence increased in boys and girls from age 2 (0.8%; 95%CI, 0.8-0.9 in both sexes) until peaking at age 7 in girls (17.3%; 95%CI, 17.1-17.5) and age 9 in boys (24.1%; 95%CI 23.9-24.3). The highest and lowest obesity prevalences were observed in Murcia and Navarre. Overall obesity prevalence trends decreased from 2005 to 2017 in all age-sex groups and in most regions. Highest obesity incidence rates were found in children aged 6 to 7 years, (4.5 [4.5-4.5] and 3.5 [3.5-3.5] new obesity cases per 100 person-years in boys and girls, respectively). Boys had higher prevalence and incidence rates than girls across all regions. Overweight/obesity prevalence and incidence rates and their trends were consistently higher than the obesity results, although a similar pattern was observed across sex and age.Conclusions: Overweight and obesity prevalence slightly decreased in Spain from 2005 to 2017, but regional, sex, and age differences persisted. Because incidence peaked around the age of 6 years, it may be important to begin health promotion programs at an early age (AU)

Family-based intervention to prevent childhood obesity among school-age children of low socioeconomic status: study protocol of the FIVALIN project.

BACKGROUND: Childhood obesity represents a global public health crisis: the number of obese children and adolescents (aged 5-19 years) worldwide has risen tenfold in the past four decades. The vast majority of overweight and obese children live in high-income countries, and low socio-economic status (SES) is a significant risk factor. Family Based Interventions (FBI) have demonstrated positive results in preventing obesity, although these results are strongly influenced by SES. Moreover, we still poorly understand how FBI can determine a positive trend in weight status in low-income communities. Therefore, there is an urgent need to define and evaluate innovative and multi-target projects to reduce obesity risk behaviors and health inequalities and the present study aims to present the study protocol of FIVALIN a FBI that pretends to achieve this goal. METHODS: We will conduct a quasi-experimental design within 60 Community Child Centers (CCC) in Barcelona metropolitan area. Each cluster (CCC) will be assigned by convenience to the intervention and control groups. For the whole study, a total of 810 children aged 8-12 years and 600 parents will be recruited during 3 consecutive editions (1st - 2019/2020; 2nd - 2020/2021; 3rd - 2021/2022) of 10 months each. The action is a regular multicomponent health-promotion intervention targeting children, families, and CCC. All activities are based on the Motivational Interviewing (MI) approach and will focus on promoting good dietary habits, physical activity, appropriate screen time and sleep duration, and psychological well-being. The control group participate in a unique workshop on general awareness of healthy lifestyles for families. We will perform a comparative analysis of the evolution of weight status, healthy lifestyles, and socioeconomic variables, between the intervention and control groups. DISCUSSION: There is a need for more evidence on how to target and evaluate holistic interventions in low SES families. Our multi-targeting intervention for obesity prevention tackles risky behaviors that go beyond diet and physical activity (PA). Therefore, future interventions can effectively promote all the behavioral domains that determine trends in the weight status. TRIAL REGISTRATION: ISRCTN Registry: ISRCRN12682870 . Registered 9 July 2020. Retrospectively registered. Protocol version: 30 April 2021, version 5.

The importance of specialized sleep investigations in children with a suprasellar tumor.

PURPOSE: Disruption of sleep has great impact on quality of life. In children with a suprasellar tumor and hypothalamic-pituitary dysfunction, the circadian rhythm may be disturbed causing sleep problems. However, also other factors may influence sleep. Awareness of these different etiologies and careful history taking with appropriate additional diagnostics will aid in restoring sleep quality. METHODS: We present the workup of 4 cases with a suprasellar tumor and disturbances of sleep initiation, sleep maintenance, and daytime sleepiness. In parallel, we developed a flowchart, to aid clinicians in the diagnostics of sleep problems in children after treatment for a (supra) sellar brain tumor. RESULTS: All four patients, known with hypopituitarism, presented with sleep complaints and increased daytime sleepiness. In all four, the cause of sleep problems showed to be different. In the first case, sleep evaluation revealed a severe obstructive sleep apnea, whereupon nocturnal ventilation was started. The second case revealed poor sleep hygiene in combination with an obsessive compulsive disorder. Sleep hygiene was addressed and psychiatric consultation was offered. Dexamphetamine treatment was started to reduce her obsessive compulsive complaints. The third case showed a delayed sleep phase syndrome, which improved by educational support. The fourth case revealed a secondary organic hypersomnia for which modafinil treatment was started. CONCLUSION: Sleep disturbances in children with hypopituitarism due to a (supra) sellar tumor can have different entities which require specific therapy. Awareness of these different entities is important to enable appropriate counseling. Referral to an expertise sleep center may be advised, if standard educational support is insufficient.

Improved xylose uptake in Saccharomyces cerevisiae due to directed evolution of galactose permease Gal2 for sugar co-consumption.

AIMS: Saccharomyces cerevisiae does not express any xylose-specific transporters. To enhance the xylose uptake of S. cerevisiae, directed evolution of the Gal2 transporter was performed. METHODS AND RESULTS: Three rounds of error-prone PCR were used to generate mutants with improved xylose-transport characteristics. After developing a fast and reliable high-throughput screening assay based on flow cytometry, eight mutants were obtained showing an improved uptake of xylose compared to wild-type Gal2 out of 41 200 single yeast cells. Gal2 variant 2·1 harbouring five amino acid substitutions showed an increased affinity towards xylose with a faster overall sugar metabolism of glucose and xylose. Another Gal2 variant 3·1 carrying an additional amino acid substitution revealed an impaired growth on glucose but not on xylose. CONCLUSIONS: Random mutagenesis of the S. cerevisiae Gal2 led to an increased xylose uptake capacity and decreased glucose affinity, allowing improved co-consumption. SIGNIFICANCE AND IMPACT OF THE STUDY: Random mutagenesis is a powerful tool to evolve sugar transporters like Gal2 towards co-consumption of new substrates. Using a high-throughput screening system based on flow-through cytometry, various mutants were identified with improved xylose-transport characteristics. The Gal2 variants in this work are a promising starting point for further engineering to improve xylose uptake from mixed sugars in biomass.

Treatment of the sacroiliac joint in patients with leg pain: a randomized-controlled trial.

PURPOSE: The sacroiliac joint (SIJ) may be a cause of sciatica. The aim of this study was to assess which treatment is successful for SIJ-related back and leg pain. METHODS: Using a single-blinded randomised trial, we assessed the short-term therapeutic efficacy of physiotherapy, manual therapy, and intra-articular injection with local corticosteroids in the SIJ in 51 patients with SIJ-related leg pain. The effect of the treatment was evaluated after 6 and 12 weeks. RESULTS: Of the 51 patients, 25 (56 %) were successfully treated. Physiotherapy was successful in 3 out of 15 patients (20 %), manual therapy in 13 of the 18 (72 %), and intra-articular injection in 9 of 18 (50 %) patients (p = 0.01). Manual therapy had a significantly better success rate than physiotherapy (p = 0.003). CONCLUSION: In this small single-blinded prospective study, manual therapy appeared to be the choice of treatment for patients with SIJ-related leg pain. A second choice of treatment to be considered is an intra-articular injection.

Liquid-liquid extraction of fermentation inhibiting compounds in lignocellulose hydrolysate.

Several compounds that are formed or released during hydrolysis of lignocellulosic biomass inhibit the fermentation of the hydrolysate. The use of a liquid extractive agent is suggested as a method for removal of these fermentation inhibitors. The method can be applied before or during the fermentation. For a series of alkanes and alcohols, partition coefficients were measured at low concentrations of the inhibiting compounds furfural, hydroxymethyl furfural, vanillin, syringaldehyde, coniferyl aldehyde, acetic acid, as well as for ethanol as the fermentation product. Carbon dioxide production was measured during fermentation in the presence of each organic solvent to indicate its biocompatibility. The feasibility of extractive fermentation of hydrolysate was investigated by ethanolic glucose fermentation in synthetic medium containing several concentrations of furfural and vanillin and in the presence of decanol, oleyl alcohol and oleic acid. Volumetric ethanol productivity with 6 g/L vanillin in the medium increased twofold with 30% volume oleyl alcohol. Decanol showed interesting extractive properties for most fermentation inhibiting compounds, but it is not suitable for in situ application due to its poor biocompatibility.

[Adolescents with acute lymphatic leukaemia achieve significantly better results when treated following Dutch paediatric oncology protocols than with adult protocols]. / Adolescenten met acute lymfatische leukemie; bij behandeling volgens Nederlandse kinderoncologische protocollen significant betere resultaten dan bij het volgen van protocollen voor volwassenen.

OBJECTIVE: To compare the results, in adolescents with acute lymphatic leukaemia (ALL), of treatment according to the protocols of the Netherlands Foundation for Paediatric Oncology (DCOG) or according to the protocols for adults of the Dutch Foundation for Adult Haemato-Oncology (HOVON). DESIGN: Retrospective. METHOD: During the period from May 1985 to November 1999, 120 15-20-year-old adolescents with ALL were treated: 47 according to a DCOG protocol and 73 according to a HOVON protocol. The records of the integrated cancer centres indicate that this represented about two-thirds of all known adolescents with ALL in the Netherlands. RESULTS: Adolescents with ALL treated according to the DCOG protocols had significantly better 5-year survival rates (79% versus 38%), a significantly lower probability of relapse (27% versus 55%) and a lower treatment-related mortality (4% versus 25%) than the adolescents treated according to the HOVON protocols. CONCLUSION: This difference in outcome was most likely related to differences in structure and content between the DCOG and HOVON protocols. The HOVON protocols consisted of relatively short, intensive chemotherapy, often followed by autologous or allogeneic bone-marrow transplantation. Several treatment elements present in the DCOG protocols, such as high-dose methotrexate, reinduction therapy and maintenance therapy were absent in the HOVON protocols. Moreover, the cumulative dosages of dexamethasone, mercaptopurine, asparaginase and vincristine were lower in the HOVON protocols.

Management of hyperuricemia with rasburicase review.

Tumor lysis syndrome (TLS) is a serious complication in patients with hematological malignancies. Massive lysis of tumor cells can lead to hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcaemia. These metabolic disturbances may result in renal failure, because of precipitation of uric acid crystals and calcium phosphate salts in the kidney. The standard prophylaxis or treatment of hyperuricemia consists of decreasing uric acid production with allopurinol and facilitating its excretion by urinary alkalinization and hyperhydration. By inhibiting the enzyme xanthine oxidase, allopurinol blocks the conversion of hypoxanthine and xanthine into uric acid. An alternative treatment is urate oxidase which oxidates uric acid into allantoin. Allantoin is 5-10 times more soluble than uric acid and is therefore excreted easily. In several clinical trials rasburicase, the recombinant form of urate oxidase, has shown to be very effective in preventing and treating hyperuricemia. Rasburicase, in contrast with the non-recombinant form of urate oxidase uricozyme, is associated with a low incidence of hypersensitivity reactions. In addition to the demonstrated clinical benefit, rasburicase also proved to be a cost-effective option in the management of hyperuricemia.

Model description of bacterial 3-methylcatechol production in one- and two-phase systems.

Pseudomonas putida MC2 produces 3-methylcatechol from toluene in aqueous medium. A second phase of 1-octanol may improve total product accumulation. To optimise the design of such a biphasic process, a process model was developed, both for one- and two-phase applications. The insights obtained by the model predictions showed the importance of different process parameters (like growth substrate concentration and partition coefficient) on growth of biomass, accumulation of 3-methylcatechol and processing time. For future applications, the process model can be used to ensure enough extraction capacity from aqueous to octanol phase. It is a useful tool to define the optimum process conditions, depending on the desired optimisation parameter: product concentration or processing time.

Anaerobic oxidation of 2-chloroethanol under denitrifying conditions by Pseudomonas stutzeri strain JJ.

A bacterium that uses 2-chloroethanol as sole energy and carbon source coupled to denitrification was isolated from 1,2-dichloroethane-contaminated soil. Its 16 S rDNA sequence showed 98% similarity with the type strain of Pseudomonas stutzeri (DSM 5190) and the isolate was tentatively identified as Pseudomonas stutzeri strain JJ. Strain JJ oxidized 2-chloroethanol completely to CO(2) with NO(3)(- )or O(2) as electron acceptor, with a preference for O(2) if supplied in combination. Optimum growth on 2-chloroethanol with nitrate occurred at 30 degrees C with a mu(max) of 0.14 h(-1) and a yield of 4.4 g protein per mol 2-chloroethanol metabolized. Under aerobic conditions, the mu(max) was 0.31 h(-1). NO(2)(-) also served as electron acceptor, but reduction of Fe(OH)(3), MnO(2), SO(4)(2-), fumarate or ClO(3)(-) was not observed. Another chlorinated compound used as sole energy and carbon source under aerobic and denitrifying conditions was chloroacetate. Various different bacterial strains, including some closely related Pseudomonas stutzeri strains, were tested for their ability to grow on 2-chloroethanol as sole energy and carbon source under aerobic and denitrifying conditions, respectively. Only three strains, Pseudomonas stutzeri strain LMD 76.42, Pseudomonas putida US2 and Xanthobacter autotrophicus GJ10, grew aerobically on 2-chloroethanol. This is the first report of oxidation of 2-chloroethanol under denitrifying conditions by a pure bacterial culture.

Failure of a recombinant Schistosoma bovis-derived glutathione S-transferase to protect cattle against experimental Fasciola hepatica infection.

The potential of a recombinant Schistosoma bovis 28-kDa glutathione S-transferase (rSb28GST) to protect cattle against Fasciola hepatica was tested in a vaccination trial. Thirty two calves were randomly divided into four groups of eight animals. Calves of the three vaccine groups received two intramuscular injections at 3 weeks interval, of 0.250mg rSb28GST in either aluminium hydroxide (Al(OH)(3)), Quil A, or PBS emulsified in an equal volume of Freund's complete adjuvant (FCA).Animals of the control group received injections of Al(OH)(3)/PBS only. All animals were challenged orally with a total of 360 metacercariae of F. hepatica, spread over 6 weeks. All groups of vaccinated animals produced measurable IgG antibody titers to rSb28GST after vaccination. Animals immunised with FCA adjuvanted vaccine had the highest and more durable antibody titers and only sera from this group recognised an approximately 24kDa protein band from F. hepatica, that is thought to be a F. hepatica GST. Despite a good antibody response differences in cumulative faecal egg output between the groups were not statistically significant. In addition, no significant difference was found between groups in terms of total worm numbers or percentage of immature flukes recovered at necropsy. In conclusion, the recombinant S. bovis 28kDa GST was not found to adequately protect cattle against experimental F. hepatica challenge, using either aluminium hydroxide, Quil A or FCA as adjuvant.

The relationship between faecal egg counts, worm burden and tissue egg counts in early Schistosoma mattheei infections in cattle.

The relationships between schistosome faecal egg counts (EPG), total tissue egg counts (TEC) and adult female worm burdens (FW) recorded at post-mortem examination of 30 Friesian calves from three different field trials were analysed. The calves in study 1 (n=14) had been exposed to natural Schistosoma mattheei infections for 2 months, those of study 2 (n=9) for between 4 and 12 months, and those in study 3 (n=7) for 8 months. No clinical schistosomiasis was observed in any of the groups, and at perfusion, EPG's varied from 5 to 210, TEC's from 28,800 to 2,439,400 and FW's from 11 to 1218. There was as much variation in EPG, TEC and FW between calves with the same duration of exposure as between calves with different duration of exposure. There were very similar significant positive relationships between log transformed FW and log transformed EPG in all three groups (P<0.007, R2>0.46, slopes 0.957-1.015). There were also significant positive relationships between log transformed FW and log transformed TEC in all three groups (P<0.034, R2>0.45) and between log transformed TEC and log transformed EPG in all three groups (P<0.025, R2>0.48). All three studies had a linear relationship between log transformed FW and log transformed EPG with a slope value close to 1 (P>0.845 for different from one). This indicates that there was no evidence of density dependence in the three studies for the relationship between FW and EPG. In contrast, there was no consistent relationship (in terms of slope) between either log transformed TEC and log transformed FW in the three studies (after correcting for differential duration of exposure), or log transformed TEC and log transformed EPG. For all three sets of comparisons the predictability of one parameter based on another was poor for a single sample.

Transplacental transfer of schistosomal circulating anodic antigens in cows.

The present work investigated the transplacental passage of circulating anodic schistosome antigens (CAA) and the production of foetal antibodies in response to antigenic stimulation in Schistosoma mattheei infected cows. Three groups were available: six calves born to non-infected cows received colostrum from a pool from non-infected cows (group 1), six calves born to non-infected cows (group 2) and six calves born to infected cows (group 3) received colostrum from a pool from infected cows. Schistosoma-specific IgG1 antibody and CAA levels were measured in the colostrum pools, the sera collected from the cows, and the sera collected from the calves at birth, after intake of colostrum and at day 30. The specific IgG1 antibody levels were significantly higher in the sera from cows of group 3. In four cows of group 3 high CAA levels were detected. The specific IgG1 antibody levels were 0.646 and 0.176 OD for the infected and non-infected colostrum pool, respectively, and the CAA levels were 5667 and 2557 pg CAA/mL, respectively. At birth high levels of specific IgG1 antibody and CAA were detected in 4 calves of group 3; levels in the other two calves were negligible. After intake of colostrum, specific IgG1 antibody levels of group 1 increased slightly at day 1 to become again insignificant at day 30. In group 2 specific IgG1 antibody levels increased significantly between days 0 and 1, to decrease, although not significantly, at day 30. Finally, in group 3 the delta OD values increased at day 1 and remained high until day 30. After intake of colostrum the CAA level increased very slightly for groups 1 and 2 to become again undetectable at day 30. In group 3 a nonsignificant decrease in CAA levels was observed at day 1 followed by a further significant decrease to reach low levels at day 30. The suggested intrauterine antigenic stimulation may be important not only for generating immune responses to natural early infections, but also for enhancing the immunogenicity and efficacy of vaccines administered to newborns.

The influence of colostrum on early Schistosoma mattheei infections in calves.

The study investigated whether the susceptibility of calves to an early Schistosoma mattheei infection may be modified by intake of colostrum from infected cows. Twelve calves born to non-infected mothers were randomly divided into 2 groups of 6. The animals from group 1 were fed colostrum originating from a pool collected from non-infected cows, the calves from group 2 received colostrum from a pool collected from cows infected with S. mattheei. One month after birth all calves were infected by exposure to 1000 cercariae of a local strain of S. mattheei, and perfused 12 weeks later to determine the worm- and tissue egg counts. IgG(H+L), IgG1, IgG2 and IgA levels against soluble adult worm antigen preparation of S. bovis (SWAP bovis) were analysed in both colostrum pools and in the serum from the calves collected during the study before and after receiving colostrum, then on days 7, 30, 73 and 122. Faecal egg counts were determined from day 73 onwards. The IgG(H+L), IgG1 and IgA levels of the positive colostrum pool were higher than those of the negative pool. Calves of group 2 showed significantly higher levels of IgG(H+L) and IgG1 until day 73, to reach equal levels at necropsy. Calves of group 2 showed significant reductions of 42, 28 and 42% in total worm counts, female worm counts, and tissue egg counts, respectively, and a reduction of 25% in cumulative faecal egg counts. These findings indicate that there was a significant impact of colostrum on the parasitological and serological course of early S. mattheei infections.

High-rate 3-methylcatechol production in Pseudomonas putida strains by means of a novel expression system.

The bioconversion of toluene into 3-methylcatechol was studied as a model system for the production of valuable 3-substituted catechols in general. For this purpose, an improved microbial system for the production of 3-methylcatechol was obtained. Pseudomonas putida strains containing the todC1C2BAD genes involved in the conversion of toluene into 3-methylcatechol were used as hosts for introducing extra copies of these genes by means of a novel integrative expression system. A construct was made containing an expression cassette with the todC1C2BAD genes cloned under the control of the inducible regulatory control region for naphthalene and phenanthrene degradation, nagR. Introducing this construct into wild-type P. putida F1, which degrades toluene via 3-methylcatechol, or into mutant P. putida F107, which accumulates 3-methylcatechol, yielded biocatalysts carrying multiple copies of the expression cassette. As a result, up to 14 mM (1.74 g l(-1)) of 3-methylcatechol was accumulated and the specific production rate reached a level of 105 micromol min(-1) g(-1) cell dry weight, which is four times higher than other catechol production systems. It was shown that these properties were kept stable in the biocatalysts without the need for antibiotics in the production process. This is an important step for obtaining designer biocatalysts.

Transposon mutations in the flagella biosynthetic pathway of the solvent-tolerant Pseudomonas putida S12 result in a decreased expression of solvent efflux genes.

Fourteen solvent-sensitive transposon mutants were generated from the solvent-tolerant Pseudomonas putida strain S12 by applying the TnMod-KmO mutagenesis system. These mutants were unable to grow in the presence of octanol and toluene. By cloning the region flanking the transposon insertion point a partial sequence of the interrupted genes was determined. Comparison of the deduced amino acid sequences with a protein database revealed the following interrupted putative gene products: organic solvent efflux proteins SrpA and SrpB, the flagellar structural proteins FlgK, FlaG, FliI, FliC, and FliH, the transcriptional activator FleQ, the alternative RNA polymerase sigma factor RpoN, and the flagellum-specific RNA polymerase sigma factor FliA (RpoF). The transposon mutants, except for the organic solvent efflux mutants, were nonmotile as determined by a swarm assay and the formation of the flagellum was totally impaired. Expression studies with a srp promoter probe showed a decreased expression of the SrpABC efflux pump in the nonmotile mutants.

Production of 3-nitrocatechol by oxygenase-containing bacteria: optimization of the nitrobenzene biotransformation by Nocardia S3.

Twenty-one microorganisms were screened for their ability to convert nitroaromatics into 3-nitrocatechol as a result of the action of an oxygenase. Cultures containing toluene dioxygenases and phenol monooxygenases accumulated 3-nitrocatechol during incubation with nitrobenzene and nitrophenol, respectively. Nocardia S3 was selected and studied in more detail. Toluene-pregrown cultures were able to degrade nitrobenzene with a concomitant formation of 3-nitrocatechol. The rates of nitrobenzene utilization decreased throughout the biotransformation period and finally the accumulation ceased. The gradual deterioration of the biotransformation rates was not a consequence of depletion of the NADH pool, but was due to the accumulation of 3-nitrocatechol. The inhibition of nitrobenzene biotransformation by 3-nitrocatechol greatly impacts 3-nitrocatechol production processes.