RESUMEN
AIMS: To develop an innovative community-academic partnership to advance, test and promote intimate partner violence screening and referral protocols by comparing the effect of integrating intimate partner violence advocates versus enhancing medical training in medical clinic settings serving women from vulnerable populations. Detecting intimate partner violence in healthcare settings allows for survivors to connect to safety and referral resources prior to violence escalating. Screening for intimate partner violence and connecting patients to referral resources requires creating a safe and trusting relationship between healthcare providers and patients. Developing screening and referral protocols responsive to survivors' needs requires involvement of clinic staff, survivors and community agencies that support survivors. DESIGN: Three phases of the project include Discovery, Implementation and Dissemination. Mixed-methodology will help in understanding current practices and effects of interventions. METHODS: Actions included in each phase: Discovery: 1) nurse-led focus groups of clinic staff, providers and survivors to understand current clinic practices; 2) retrospective chart review of the number of screens performed, positive screens detected and interventions performed. IMPLEMENTATION: 1) randomization of patients to be interviewed by a trained advocate or by healthcare provider with enhanced training; and 2) assess the number of screenings and referrals performed in each arm and 3) evaluate outcomes of intervention. Dissemination through: presentations, manuscripts and policy recommendations at the institutional and regional level. This IRB-approved proposal was funded in July 2021 by an Advancing a Healthier Wisconsin grant. DISCUSSION: The partnership has improved channels of communication and understanding between diverse clinical care providers, survivors and community agency staff as they navigate the complex challenges to the development and integration of screening and referral protocols. IMPACT: This project will provide evidence of the most effective intimate partner violence screening and referral methodology that can be utilized in a wide variety of medical settings.
Asunto(s)
Violencia de Pareja , Humanos , Femenino , Estudios Retrospectivos , Violencia de Pareja/prevención & control , Instituciones de Atención Ambulatoria , Estado de Salud , Atención a la SaludRESUMEN
BACKGROUND: The Comparative Effectiveness Dementia and Alzheimer's Registry (CEDAR) trial demonstrated that individualized, multi-domain interventions improved cognition and reduced the risk of Alzheimer's disease (AD). As biological sex is a significant risk factor for AD, it is essential to explore the differential effectiveness of targeted clinical interventions in women vs. men. METHODS: Patients were recruited from an Alzheimer's Prevention Clinic. Subjects with normal cognition, subjective cognitive decline, or asymptomatic preclinical AD were classified as "Prevention". Subjects with mild cognitive impairment due to AD or mild AD were classified as "Early Treatment." The primary outcome was the change from baseline to 18-months on the modified-Alzheimer's Prevention Cognitive Composite. Secondary outcomes included a cognitive aging composite, AD and cardiovascular (CV) risk scales, and serum biomarkers. Subjects who adhered to > 60% of recommendations in the CEDAR trial were included in this a priori sub-group analysis to examine whether individualized intervention effects were modified by sex (n=80). RESULTS: In the Prevention group, both women (p=0.0205) and men (p=0.0044) demonstrated improvements in cognition with no sex differences (p=0.5244). In the Early Treatment group, there were also no significant sex differences in cognition (p=0.3299). In the Prevention group, women demonstrated greater improvements in the Multi-Ethnic Study of Atherosclerosis risk score (MESA-RS) than men (difference=1.5, p=0.0013). Women in the Early Treatment group demonstrated greater improvements in CV Risk Factors, Aging and Incidence of Dementia (CAIDE) risk score (difference=2.3, p=0.0067), and the MESA-RS (difference=4.1, p<0.001). CONCLUSIONS: Individualized multi-domain interventions are equally effective at improving cognition in women and men. However, personally-tailored interventions led to greater improvements in calculated AD and CV risk, and CV blood biomarkers, in women compared to men. Future study in larger cohorts is necessary to further define sex differences in AD risk reduction in clinical practice.
Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Femenino , Humanos , Masculino , Enfermedad de Alzheimer/tratamiento farmacológico , Biomarcadores , Cognición , Disfunción Cognitiva/psicología , Factores de Riesgo , Ensayos Clínicos como AsuntoRESUMEN
The dynamic regulation of DNA methylation in postmitotic neurons is necessary for memory formation and other adaptive behaviors. Ten-eleven translocation 1 (TET1) plays a part in these processes by oxidizing 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), thereby initiating active DNA demethylation. However, attempts to pinpoint its exact role in the nervous system have been hindered by contradictory findings, perhaps due in part, to a recent discovery that two isoforms of the Tet1 gene are differentially expressed from early development into adulthood. Here, we demonstrate that both the shorter transcript (Tet1S ) encoding an N-terminally truncated TET1 protein and a full-length Tet1 (Tet1FL ) transcript encoding canonical TET1 are co-expressed in the adult mouse brain. We show that Tet1S is the predominantly expressed isoform and is highly enriched in neurons, whereas Tet1FL is generally expressed at lower levels and more abundant in glia, suggesting their roles are at least partially cell type-specific. Using viral-mediated, isoform and neuron-specific molecular tools, we find that the individual repression of each transcript leads to the dysregulation of unique gene ensembles and contrasting changes in basal synaptic transmission. In addition, Tet1S repression enhances, while Tet1FL impairs, hippocampal-dependent memory in male mice. Together, our findings demonstrate that each Tet1 isoform serves a distinct role in the mammalian brain.SIGNIFICANCE STATEMENT In the brain, activity-dependent changes in gene expression are required for the formation of long-term memories. DNA methylation plays an essential role in orchestrating these learning-induced transcriptional programs by influencing chromatin accessibility and transcription factor binding. Once thought of as a stable epigenetic mark, DNA methylation is now known to be impermanent and dynamically regulated, driving neuroplasticity in the brain. We found that Tet1, a member of the ten-eleven translocation (TET) family of enzymes that mediates removal of DNA methyl marks, is expressed as two separate isoforms in the adult mouse brain and that each differentially regulates gene expression, synaptic transmission and memory formation. Together, our findings demonstrate that each Tet1 isoform serves a distinct role in the CNS.
Asunto(s)
Encéfalo/fisiología , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/fisiología , Regulación de la Expresión Génica/genética , Memoria/fisiología , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/fisiología , Transmisión Sináptica/genética , Transmisión Sináptica/fisiología , Animales , Ansiedad/genética , Ansiedad/psicología , Condicionamiento Clásico , Epigénesis Genética/fisiología , Miedo/psicología , Hipocampo/fisiología , Isomerismo , Masculino , Ratones , Ratones Endogámicos C57BL , Neuroglía/fisiología , Neuronas/fisiologíaRESUMEN
Background: Research has shown that number of and blast-related Traumatic Brain Injuries (TBI) are associated with higher levels of service-connected disability (SCD) among US veterans. This study builds and tests a prediction model of SCD based on combat and training exposures experienced during active military service.Methods: Based on 492 US service member and veteran data collected at four Department of Veterans Affairs (VA) sites, traditional and Machine Learning algorithms were used to identify a best set of predictors and model type for predicting %SCD ≥50, the cut-point that allows for veteran access to 0% co-pay for VA health-care services.Results: The final model of predicting %SCD ≥50 in veterans revealed that the best blast/injury exposure-related predictors while deployed or non-deployed were: 1) number of controlled detonations experienced, 2) total number of blast exposures (including controlled and uncontrolled), and 3) the total number of uncontrolled blast and impact exposures.Conclusions and Relevance: We found that the highest blast/injury exposure predictor of %SCD ≥50 was number of controlled detonations, followed by total blasts, controlled or uncontrolled, and occurring in deployment or non-deployment settings. Further research confirming repetitive controlled blast exposure as a mechanism of chronic brain insult should be considered.
Asunto(s)
Lesiones Traumáticas del Encéfalo/epidemiología , Trastornos de Combate/epidemiología , Personas con Discapacidad , Personal Militar , United States Department of Veterans Affairs/tendencias , Veteranos , Adulto , Anciano , Traumatismos por Explosión/diagnóstico , Traumatismos por Explosión/epidemiología , Traumatismos por Explosión/psicología , Lesiones Traumáticas del Encéfalo/diagnóstico , Lesiones Traumáticas del Encéfalo/psicología , Estudios de Cohortes , Trastornos de Combate/diagnóstico , Trastornos de Combate/psicología , Personas con Discapacidad/psicología , Femenino , Predicción , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Personal Militar/psicología , Modelos Teóricos , Estados Unidos/epidemiología , Veteranos/psicología , Adulto JovenRESUMEN
BACKGROUND: The U.S. Veterans Health Administration (VHA) provides depression treatment to veterans with Traumatic Brain Injury (TBI). VHA costs of comorbid TBI-depression were estimated by Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) status over 14 years. METHODS: VHA-USING veterans with TBI DIAGNOSED IN 2000-2010 were followed through FY2014. TBI severity was determined using the Department of Defense criteria. Depression was identified by the Elixhauser algorithm. Generalized linear and seemingly unrelated regression models were used to estimate the impact of depression on annual per veteran and total VHA inpatient, outpatient, and pharmaceutical costs, by OEF/OIF status. RESULTS: A total of 66.57% of pre-OEF/OIF and 87.46% of OEF/OIF veterans had depression. Depression was estimated to increase annual total ($1,847), outpatient ($1,558), and pharmaceutical ($287) costs for pre-OEF/OIF, and $1,228, $1,685, and $191 for OEF/OIF veterans. However, depression was estimated to lower annual inpatient costs by $648 per OEF/OIF veteran. The annual VHA cost for all veterans with comorbid TBI-depression was estimated at $1,101,329,953. CONCLUSIONS: The estimated annual cost for Veterans with comorbid TBI-depression was more than $1 billion. TBI and depression screening/treatment may result in reduced inpatient VHA costs in OEF/OIF veterans exposed to TBI. VHA policymakers should consider screening for TBI and depression in pre-OEF/OIF veterans.
RESUMEN
Prenatal development is a critical period for programming of neurological disease. Preeclampsia, a pregnancy complication involving oxidative stress in the placenta, has been associated with long-term health implications for the child, including an increased risk of developing schizophrenia and autism spectrum disorders in later life. To investigate if molecules released by the placenta may be important mediators in foetal programming of the brain, we analysed if placental tissue delivered from patients with preeclampsia secreted molecules that could affect cortical cells in culture. Application of culture medium conditioned by preeclamptic placentae to mixed cortical cultures caused changes in neurons and astrocytes that were related to key changes observed in brains of patients with schizophrenia and autism, including effects on dendrite lengths, astrocyte number as well as on levels of glutamate and γ-aminobutyric acid receptors. Treatment of the placental explants with an antioxidant prevented neuronal abnormalities. Furthermore, we identified that bidirectional communication between neurons and astrocytes, potentially via glutamate, is required to produce the effects of preeclamptic placenta medium on cortical cells. Analysis of possible signalling molecules in the placenta-conditioned medium showed that the secretion profile of extracellular microRNAs, small post-transcriptional regulators, was altered in preeclampsia and partially rescued by antioxidant treatment of the placental explants. Predicted targets of these differentially abundant microRNAs were linked to neurodevelopment and the placenta. The present study provides further evidence that the diseased placenta may release factors that damage cortical cells and suggests the possibility of targeted antioxidant treatment of the placenta to prevent neurodevelopmental disorders.
Asunto(s)
Cianobacterias , Endotoxinas/toxicidad , Exposición a Riesgos Ambientales/efectos adversos , Enfermedades Gastrointestinales/epidemiología , Microbiología del Agua , Enfermedad Aguda , Adolescente , Adulto , Niño , Preescolar , Cianobacterias/aislamiento & purificación , Endotoxinas/análisis , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Recreación , Adulto JovenRESUMEN
Increasing permafrost thaw, driven by climate change, has the potential to result in organic carbon stores being mineralized into carbon dioxide (CO2) and methane (CH4) through microbial activity. This study examines the effect of increasing temperature on community structure and metabolic activity of methanogens from the Canadian High Arctic, in an attempt to predict how warming will affect microbially controlled CH4 soil flux. In situâ CO2 and CH4 flux, measured in 2010 and 2011 from ice-wedge polygons, indicate that these soil formations are a net source of CO2 emissions, but a CH4 sink. Permafrost and active layer soil samples were collected at the same sites and incubated under anaerobic conditions at warmer temperatures, with and without substrate amendment. Gas flux was measured regularly and indicated an increase in CH4 flux after extended incubation. Pyrosequencing was used to examine the effects of an extended thaw cycle on methanogen diversity and the results indicate that in situ methanogen diversity, based on the relative abundance of the 16S ribosomal ribonucleic acid (rRNA) gene associated with known methanogens, is higher in the permafrost than in the active layer. Methanogen diversity was also shown to increase in both the active layer and permafrost soil after an extended thaw. This study provides evidence that although High Arctic ice-wedge polygons are currently a sink for CH4, higher arctic temperatures and anaerobic conditions, a possible result of climate change, could result in this soil becoming a source for CH4 gas flux.
Asunto(s)
Bacterias/aislamiento & purificación , Bacterias/metabolismo , Metano/metabolismo , Microbiología del Suelo , Regiones Árticas , Bacterias/química , Bacterias/clasificación , Canadá , Cinética , Metano/química , Suelo/química , TemperaturaRESUMEN
Treatment with histone deacetylase inhibitors (HDACI) results in potent cytotoxicity of a variety of cancer cell types, and these drugs are used clinically to treat hematological tumors. They are known to repress the transcription of ERBB2 and many other oncogenes, but little is known about this mechanism. Using global run-on sequencing (GRO-seq) to measure nascent transcription, we find that HDACI cause transcriptional repression by blocking RNA polymerase II elongation. Our data show that HDACI preferentially repress the transcription of highly expressed genes as well as high copy number genes in HER2+ breast cancer genomes. In contrast, genes that are activated by HDACI are moderately expressed. We analyzed gene copy number in combination with microarray and GRO-seq analysis of expression level, in normal and breast cancer cells to show that high copy number genes are more likely to be repressed by HDACI than non-amplified genes. The inhibition of transcription of amplified oncogenes, which promote survival and proliferation of cancer cells, might explain the cancer-specific lethality of HDACI, and may represent a general therapeutic strategy for cancer.
Asunto(s)
Antineoplásicos/farmacología , Inhibidores de Histona Desacetilasas/farmacología , Ácidos Hidroxámicos/farmacología , Elongación de la Transcripción Genética/efectos de los fármacos , Neoplasias de la Mama , Línea Celular Tumoral , Femenino , Dosificación de Gen , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Silenciador del Gen/efectos de los fármacos , Genoma Humano , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , Oncogenes , ARN Polimerasa II/antagonistas & inhibidores , ARN Polimerasa II/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Iniciación de la Transcripción Genética , TranscriptomaRESUMEN
AIMS: To explore rhizospheric microbial communities from Arctic native plant species evaluating their bacterial hydrocarbon-degrading capacities. METHODS AND RESULTS: Eriophorum scheuchzeri, Potentilla cf. rubricaulis, Oxyria digyna, Salix arctica and Puccinellia angustata plant species were collected at Eureka (Canadian high Arctic) along with their rhizospheric soil samples. Their bacterial community fingerprints (16S rRNA gene, DGGE) were distinctive encompassing members from the phyla: Bacteroidetes, Firmicutes, Actinobacteria and Proteobacteria. Isolated diesel-degrading bacteria belonged to the phyla Actinobacteria and Proteobacteria. Strains of Mycobacterium, Nocardia, Rhodococcus, Intrasporangiaceae, Leifsoni and Arthrobacter possessed alkB and Pseudomonas possessed both ndoB and xylE gene sequences. Two Rhodococcus strains mineralized [1-(14) C] hexadecane at 5 and -5°C. From the rhizosphere of P. angustata, larger numbers of hydrocarbon-degrading bacteria were isolated than from other plant rhizosphere samples and all three genes alkB (from Actinobacteria), ndoB and xylE (from Pseudomonas) were detected by PCR. CONCLUSIONS: (i) Arctic plants have unique rhizospheric bacterial communities. (ii) P. angustata has potential for phytoremediation research at high Arctic soils. (iii) Isolated bacteria mineralized hydrocarbons at ambient low temperatures. SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, this is the first rhizospheric exploration examining the phytoremediation potential of five Arctic plants and evaluating their microbial hydrocarbon-degrading capacities.
Asunto(s)
Hidrocarburos/metabolismo , Magnoliopsida/microbiología , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Actinobacteria/clasificación , Actinobacteria/genética , Actinobacteria/metabolismo , Alcanos/metabolismo , Regiones Árticas , Biodegradación Ambiental , Canadá , Recuento de Colonia Microbiana , Genes Bacterianos , Filogenia , Proteobacteria/clasificación , Proteobacteria/genética , Proteobacteria/metabolismo , ARN Ribosómico 16S , Rizosfera , SueloRESUMEN
A DNA microarray (Enteroarray) was designed with probes targeting four species-specific taxonomic identifiers to discriminate among 18 different enterococcal species, while other probes were designed to identify 18 virulence factors and 174 antibiotic resistance genes. In total, 262 genes were utilized for rapid species identification of enterococcal isolates, while characterizing their virulence potential through the simultaneous identification of endogenous antibiotic resistance and virulence genes. Enterococcal isolates from broiler chicken farms were initially identified by using the API 20 Strep system, and the results were compared to those obtained with the taxonomic genes atpA, recA, pheS, and ddl represented on our microarray. Among the 171 isolates studied, five different enterococcal species were identified by using the API 20 Strep system: Enterococcus faecium, E. faecalis, E. durans, E. gallinarum, and E. avium. The Enteroarray detected the same species as API 20 Strep, as well as two more: E. casseliflavus and E. hirae. Species comparisons resulted in 15% (27 isolates) disagreement between the two methods among the five API 20 Strep identifiable species and 24% (42 isolates) disagreement when considering the seven Enteroarray identified species. The species specificity of key antibiotic and virulence genes identified by the Enteroarray were consistent with the literature adding further robustness to the redundant taxonomic probe data. Sequencing of the cpn60 gene further confirmed the complete accuracy of the microarray results. The new Enteroarray should prove to be a useful tool to accurately genotype strains of enterococci and assess their virulence potential.
Asunto(s)
Pollos/microbiología , Farmacorresistencia Bacteriana , Enterococcus/genética , Enterococcus/aislamiento & purificación , Animales , Técnicas de Tipificación Bacteriana , Secuencia de Bases , ADN Bacteriano/genética , Enterococcus/clasificación , Enterococcus/patogenicidad , Proteínas de Escherichia coli , Proteínas Fimbrias , Análisis de Secuencia por Matrices de Oligonucleótidos , Péptido Sintasas , Reacción en Cadena de la Polimerasa , Rec A Recombinasas , Análisis de Secuencia de ADN , Virulencia , Factores de Virulencia/genéticaRESUMEN
No licensed vaccines are available to protect against parainfluenza virus type 3 (PIV3), a significant health risk for infants. In search of a safe vaccine, we used an alphavirus-based chimeric vector, consisting of Sindbis virus (SIN) structural proteins and Venezuelan equine encephalitis virus (VEE) replicon RNA, expressing the PIV3 hemagglutinin-neuraminidase (HN) glycoprotein (VEE/SIN-HN). We compared different routes of intramuscular (i.m.), intranasal (i.n.), or combined i.n. and i.m. immunizations with VEE/SIN-HN in hamsters. Six months after the final immunization, all hamsters were protected against live PIV3 i.n. challenge in nasal turbinates and lungs. This protection appeared to correlate with antibodies in serum, nasal turbinates and lungs. This is the first report demonstrating mucosal protection against PIV3 for an extended time following immunizations with an RNA replicon delivery system.
Asunto(s)
Alphavirus/inmunología , Membrana Mucosa/inmunología , Vacunas contra la Parainfluenza/inmunología , Virus de la Parainfluenza 3 Humana/inmunología , ARN Viral/inmunología , Replicón/inmunología , Administración Intranasal , Alphavirus/genética , Animales , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Cricetinae , Modelos Animales de Enfermedad , Virus de la Encefalitis Equina Venezolana/inmunología , Humanos , Inmunización , Inyecciones Intramusculares , Virus de la Parainfluenza 3 Humana/crecimiento & desarrollo , ARN Viral/genética , Replicón/genética , Virus Sindbis/inmunología , Vacunas Atenuadas/inmunología , Vacunas Atenuadas/uso terapéutico , Vacunas Sintéticas/inmunologíaRESUMEN
Biofilms were cultivated on polycarbonate strips in rotating annular reactors using South Saskatchewan River water during the fall of 1999 and the fall of 2001, supplemented with carbon (glucose), nitrogen (NH4Cl), phosphorus (KH2PO4), or combined nutrients (CNP), with or without hexadecane, a model compound representing aliphatic hydrocarbons used to simulate a pollutant. In fall 1999 and fall 2001, comparable denitrification activities and catabolic potentials were observed in the biofilms, implying that denitrifying populations showed similar activity patterns and catabolic potentials during the fall from year to year in this river ecosystem, when environmental conditions were similar. Both nirS and nirK denitrification genes were detected by PCR amplification, suggesting that both denitrifying bacterial subpopulations can potentially contribute to total denitrification. Between 91.7 and 99.8% of the consumed N was emitted in the form of N2, suggesting that emission of N2O, a major potent greenhouse gas, by South Saskatchewan River biofilms is low. Denitrification was markedly stimulated by the addition of CNP, and nirS and nirK genes were predominant only in the presence of CNP. In contrast, individual nutrients had no impact on denitrification and on the occurrence of nirS and nirK genes detected by PCR amplification. Similarly, only CNP resulted in significant increases in algal and bacterial biomass relative to control biofilms. Biomass measurements indicated a linkage between autotrophic and heterotrophic populations in the fall 1999 biofilms. Correlation analyses demonstrated a significant relationship (P < or = 0.05) between the denitrification rate and the biomass of algae and heterotrophic bacteria but not cyanobacteria. At the concentration assessed (1 ppb), hexadecane partially inhibited denitrification in both years, slightly more in the fall of 2001. This study suggested that the response of the anaerobic heterotrophic biofilm community may be cyclic and predictable from year to year and that there are interactive effects between nutrients and the contaminant hexadecane.
Asunto(s)
Alcanos/metabolismo , Bacterias Anaerobias/crecimiento & desarrollo , Biopelículas/crecimiento & desarrollo , Ecosistema , Eucariontes/crecimiento & desarrollo , Nitritos/metabolismo , Ríos/microbiología , Cloruro de Amonio/metabolismo , Bacterias Anaerobias/genética , Bacterias Anaerobias/metabolismo , Biomasa , Reactores Biológicos , Cianobacterias/genética , Cianobacterias/crecimiento & desarrollo , Cianobacterias/metabolismo , Eucariontes/genética , Eucariontes/metabolismo , Regulación de la Expresión Génica , Glucosa/metabolismo , Fósforo/metabolismo , Reacción en Cadena de la PolimerasaRESUMEN
Fluorescent microspheres were applied in a novel fashion during subsurface drilling of permafrost and ground ice in the Canadian High Arctic to monitor the exogenous microbiological contamination of core samples obtained during the drilling process. Prior to each drill run, a concentrated fluorescent microsphere (0.5-microm diameter) solution was applied to the interior surfaces of the drill bit, core catcher, and core tube and allowed to dry. Macroscopic examination in the field demonstrated reliable transfer of the microspheres to core samples, while detailed microscopic examination revealed penetration levels of less than 1 cm from the core exterior. To monitor for microbial contamination during downstream processing of the permafrost and ground ice cores, a Pseudomonas strain expressing the green fluorescent protein (GFP) was painted on the core exterior prior to processing. Contamination of the processed core interiors with the GFP-expressing strain was not detected by culturing the samples or by PCR to detect the gfp marker gene. These methodologies were quick, were easy to apply, and should help to monitor the exogenous microbiological contamination of pristine permafrost and ground ice samples for downstream culture-dependent and culture-independent microbial analyses.
Asunto(s)
Contaminación de Equipos , Proteínas Fluorescentes Verdes/metabolismo , Hielo/análisis , Microesferas , Microbiología del Suelo , Regiones Árticas , Bacterias/genética , Bacterias/aislamiento & purificación , Clima Frío , Medios de Cultivo , ADN/química , Proteínas Fluorescentes Verdes/genética , Microscopía Fluorescente , Reacción en Cadena de la Polimerasa/métodos , Pseudomonas/genética , Pseudomonas/metabolismo , Suelo/análisisRESUMEN
Studies were carried out to assess the influence of nutrients, dissolved oxygen (DO) concentration, and nickel (Ni) on river biofilm development, structure, function, and community composition. Biofilms were cultivated in rotating annular reactors with river water at a DO concentration of 0.5 or 7.5 mg liter(-1), with or without a combination of carbon, nitrogen, and phosphorus (CNP) and with or without Ni at 0.5 mg liter(-1). The effects of Ni were apparent in the elimination of cyanobacterial populations and reduced photosynthetic biomass in the biofilm. Application of lectin-binding analyses indicated changes in exopolymer abundance and a shift in the glycoconjugate makeup of the biofilms, as well as in the response to all treatments. Application of the fluorescent live-dead staining (BacLight Live-Dead staining kit; Molecular Probes, Eugene, Oreg.) indicated an increase in the ratio of live to dead cells under low-oxygen conditions. Nickel treatments had 50 to 75% fewer 'live' cells than their corresponding controls. Nickel at 0.5 mg liter(-1) corresponding to the industrial release rate concentration for nickel resulted in reductions in carbon utilization spectra relative to control and CNP treatments without nickel. In these cases, the presence of nickel eliminated the positive influence of nutrients on the biofilm. Other culture-dependent analyses (plate counts and most probable number) revealed no significant treatment effect on the biofilm communities. In the presence of CNP and at both DO levels, Ni negatively affected denitrification but had no effect on hexadecane mineralization or sulfate reduction. Analysis of total community DNA indicated abundant eubacterial 16S ribosomal DNA (rDNA), whereas Archaea were not detected. Amplification of the alkB gene indicated a positive effect of CNP and a negative effect of Ni. The nirS gene was not detected in samples treated with Ni at 0.5 mg liter(-1), indicating a negative effect on specific populations of bacteria, such as denitrifiers, resulting in a reduction in diversity. Denaturing gradient gel electrophoresis revealed that CNP had a beneficial impact on biofilm bacterial diversity at high DO concentrations, but none at low DO concentrations, and that the negative effect of Ni on diversity was similar at both DO concentrations. Notably, Ni resulted in the appearance of unique bands in 16S rDNA from Ni, DO, and CNP treatments. Sequencing results confirmed that the bands belonged to bacteria originating from freshwater and marine environments or from agricultural soils and industrial effluents. The observations indicate that significant interactions occur between Ni, oxygen, and nutrients and that Ni at 0.5 mg liter(-1) may have significant impacts on river microbial community diversity and function.
Asunto(s)
Biopelículas , Níquel/farmacología , Oxígeno/análisis , Ríos/microbiología , Carbono/metabolismo , ADN Bacteriano/análisis , Nitrógeno/farmacología , Óxido Nitroso/metabolismo , Fósforo/farmacologíaRESUMEN
Total community DNA from 29 noncontaminated soils and soils impacted by petroleum hydrocarbons and chloro-organics from Antarctica and Brazil were screened for the presence of nine catabolic genes, encoding alkane monooxygenase or aromatic dioxygenases, from known bacterial biodegradation pathways. Specific primers and probes targeting alkane monooxygenase genes were derived from Pseudomonas putida ATCC 29347 (Pp alkB), Rhodococcus sp. strain Q15 (Rh alkB1, Rh alkB2), and Acinetobacter sp. ADP-1 (Ac alkM). In addition, primers and probes detecting aromatic dioxygenase genes were derived from P. putida ATCC 17484 (ndoB), P. putida F1 (todC1), P. putida ATCC 33015 (xylE and cat23), and P. pseudoalcaligenes KF707 (bphA). The primers and probes were used to analyze total community DNA extracts by using PCR and hybridization analysis. All the catabolic genes, except the Ac alkM, were detected in contaminated and control soils from both geographic regions, with a higher frequency in the Antarctic soils. The alkane monooxygenase genes, Rh alkB1 and Rh alkB2, were the most frequently detected alk genes in both regions, while Pp alkB was not detected in Brazil soils. Genes encoding the aromatic dioxygenases toluene dioxygenase (todC1) and biphenyl dioxygenase (bphA) were the most frequently detected in Antarctica, and todC1 and catechol-2,3-dioxygenase (cat23) were the most frequent in Brazil soils. Hybridization analysis confirmed the PCR results, indicating that the probes used had a high degree of homology to the genes detected in the soil extracts and were effective in detecting biodegradative potential in the indigenous microbial population.
Asunto(s)
Bacterias/genética , Bacterias/metabolismo , Hidrocarburos/metabolismo , Microbiología del Suelo , Acinetobacter/genética , Regiones Antárticas , Proteínas Bacterianas/genética , Brasil , ADN Bacteriano/análisis , ADN Bacteriano/aislamiento & purificación , Metabolismo Energético , Proteínas Hierro-Azufre/genética , Hibridación de Ácido Nucleico , Oxigenasas/genética , Reacción en Cadena de la Polimerasa , Pseudomonas pseudoalcaligenes/genética , Pseudomonas putida/genética , Rhodococcus/genéticaRESUMEN
Biodegradation of petroleum hydrocarbons in cold environments, including Alpine soils, is a result of indigenous cold-adapted microorganisms able to degrade these contaminants. In the present study, the prevalence of seven genotypes involved in the degradation of n-alkanes (Pseudomonas putida GPo1 alkB; Acinetobacter spp. alkM; Rhodococcus spp. alkB1, and Rhodococcus spp. alkB2), aromatic hydrocarbons (P. putida xylE), and polycyclic aromatic hydrocarbons (P. putida ndoB and Mycobacterium sp. strain PYR-1 nidA) was determined in 12 oil-contaminated (428 to 30,644 mg of total petroleum hydrocarbons [TPH]/kg of soil) and 8 pristine Alpine soils from Tyrol (Austria) by PCR hybridization analyses of total soil community DNA, using oligonucleotide primers and DNA probes specific for each genotype. The soils investigated were also analyzed for various physical, chemical, and microbiological parameters, and statistical correlations between all parameters were determined. Genotypes containing genes from gram-negative bacteria (P. putida alkB, xylE, and ndoB and Acinetobacter alkM) were detected to a significantly higher percentage in the contaminated (50 to 75%) than in the pristine (0 to 12.5%) soils, indicating that these organisms had been enriched in soils following contamination. There was a highly significant positive correlation (P < 0.001) between the level of contamination and the number of genotypes containing genes from P. putida and Acinetobacter sp. but no significant correlation between the TPH content and the number of genotypes containing genes from gram-positive bacteria (Rhodococcus alkB1 and alkB2 and Mycobacterium nidA). These genotypes were detected at a high frequency in both contaminated (41.7 to 75%) and pristine (37.5 to 50%) soils, indicating that they are already present in substantial numbers before a contamination event. No correlation was found between the prevalence of hydrocarbon-degradative genotypes and biological activities (respiration, fluorescein diacetate hydrolysis, lipase activity) or numbers of culturable hydrocarbon-degrading soil microorganisms; there also was no correlation between the numbers of hydrocarbon degraders and the contamination level. The measured biological activities showed significant positive correlation with each other, with the organic matter content, and partially with the TPH content and a significant negative correlation with the soil dry-mass content (P < 0.05 to 0.001).
Asunto(s)
Bacterias/clasificación , Bacterias/genética , Hidrocarburos/metabolismo , Petróleo/metabolismo , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Altitud , Austria , Bacterias/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Técnicas de Tipificación Bacteriana , Biodegradación Ambiental , Frío , Recuento de Colonia Microbiana , ADN Bacteriano/análisis , Ecosistema , Genotipo , Hidrocarburos/química , Reacción en Cadena de la Polimerasa/métodosRESUMEN
The effect of contamination with the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) on an indigenous soil bacterial community was examined in two uncontaminated loam soil columns possessing native grasses. One column was spiked twice with RDX crystals for a total RDX load of 1000 mg (kg soil)(-1). The reduced metabolite of RDX degradation, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine, was observed in the column leachate, suggesting anaerobic degradation of RDX. Denaturing gradient gel electrophoresis of PCR-amplified 16S rDNA from both contaminated and uncontaminated columns produced identical banding patterns which were stable over the course of the experimental period. The bacterial diversity remained high in the contaminated column, as determined by restriction fragment length polymorphism and rarefaction analyses of random 16S rDNA clones. These combined results suggested that long-term exposure to 1000 mg RDX (kg soil)(-1) did not produce an observable effect on bacterial diversity or the numerically dominant members of the indigenous soil bacterial community.
RESUMEN
The alkane hydroxylase systems of two Rhodococcus strains (NRRL B-16531 and Q15, isolated from different geographical locations) were characterized. Both organisms contained at least four alkane monooxygenase gene homologs (alkB1, alkB2, alkB3, and alkB4). In both strains, the alkB1 and alkB2 homologs were part of alk gene clusters, each encoding two rubredoxins (rubA1 and rubA2; rubA3 and rubA4), a putative TetR transcriptional regulatory protein (alkU1; alkU2), and, in the alkB1 cluster, a rubredoxin reductase (rubB). The alkB3 and alkB4 homologs were found as separate genes which were not part of alk gene clusters. Functional heterologous expression of some of the rhodococcal alk genes (alkB2, rubA2, and rubA4 [NRRL B-16531]; alkB2 and rubB [Q15]) was achieved in Escherichia coli and Pseudomonas expression systems. Pseudomonas recombinants containing rhodococcal alkB2 were able to mineralize and grow on C(12) to C(16) n-alkanes. All rhodococcal alkane monooxygenases possessed the highly conserved eight-histidine motif, including two apparent alkane monooxygenase signature motifs (LQRH[S/A]DHH and NYXEHYG[L/M]), and the six hydrophobic membrane-spanning regions found in all alkane monooxygenases related to the Pseudomonas putida GPo1 alkane monooxygenase. The presence of multiple alkane hydroxylases in the two rhodococcal strains is reminiscent of other multiple-degradative-enzyme systems reported in Rhodococcus.
Asunto(s)
Sistema Enzimático del Citocromo P-450/genética , Oxigenasas de Función Mixta/genética , Rhodococcus/enzimología , Secuencia de Aminoácidos , Clonación Molecular , Citocromo P-450 CYP4A , Sistema Enzimático del Citocromo P-450/biosíntesis , Sistema Enzimático del Citocromo P-450/química , Escherichia coli/genética , Oxigenasas de Función Mixta/biosíntesis , Oxigenasas de Función Mixta/química , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Pseudomonas fluorescens/genética , Proteínas Recombinantes/biosíntesisRESUMEN
Anaerobic degradation of pentachlorophenol (PCP) is an example of a process that may benefit from enrichment or bioaugmentation. In one approach, enrichment acceleration was attempted by applying an on-line control-based selective stress strategy to a native anaerobic upflow sludge bed (UASB) system; this strategy linked PCP loading rate to methane production. As a result, the reactor biomass potential for PCP complete dechlorination reached a rate of 4 mg g(-1) volatile suspended solid (VSS) day(-1) within a period of 120 days. In another approach, a pure culture, Desulfitobacterium frappieri PCP-1, a strictly anaerobic Gram-positive bacterium, was used to augment the granular biomass of the UASB reactor. This also resulted in a specific degradation rate of 4 mg PCPg(-1) VSS day(-1); however, this potential was attained within 56 days. Fluorescent in situ hybridization (FISH) showed that the PCP-1 strain was able to rapidly attach to the granule and densely colonize the outer biofilm layer.