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1.
Psychiatry Res ; 258: 488-493, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28899613

RESUMEN

This study investigated comorbidity patterns in treatment-seeking veterans and currently-serving Canadian Forces members of an outpatient mental health clinic from September 2006-September 2014. Using a retrospective cohort design, latent class analysis was conducted to determine latent classes of comorbidity (including posttraumatic stress disorder [PTSD], major depressive disorder [MDD], generalized anxiety disorder, panic disorder, and alcohol use disorder [AUD]). Multiple logistic regression was used to determine which covariates (age, gender, number of deployments, and service duration) were predictors of latent class membership. Among the 486 participants, 79.2% had more than one probable mental health condition. The most common comorbidity was PTSD and MDD (61.5%), followed by PTSD and GAD (52.3%). Among those with PTSD, almost all (95%) had a subsequent condition, predominantly MDD (82.6% of those with PTSD had MDD). A two-class model was the best fitting model with a high comorbidity and a low comorbidity class. Older age and shorter service duration significantly increased the probability of being in the high comorbidity class when not controlling for member status. Results showed that treatment-seeking veterans and military personnel have high rates of comorbidity, particularly alongside PTSD. Therefore, it is critical for clinicians to be able to assess and treat comorbidity.


Asunto(s)
Trastornos Mentales/epidemiología , Trastornos Mentales/terapia , Servicios de Salud Mental/estadística & datos numéricos , Veteranos/psicología , Veteranos/estadística & datos numéricos , Adulto , Alcoholismo/epidemiología , Alcoholismo/terapia , Trastornos de Ansiedad/epidemiología , Trastornos de Ansiedad/terapia , Canadá , Comorbilidad , Trastorno Depresivo Mayor/epidemiología , Trastorno Depresivo Mayor/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastorno de Pánico/epidemiología , Trastorno de Pánico/terapia , Estudios Retrospectivos , Trastornos por Estrés Postraumático/epidemiología , Trastornos por Estrés Postraumático/terapia , Adulto Joven
2.
BMC Psychiatry ; 17(1): 211, 2017 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-28583100

RESUMEN

BACKGROUND: Past research on the association between insomnia and suicidal ideation (SI) has produced mixed findings. The current study explored the relationship between insomnia, SI, and past-year mental health status among a large Canadian Forces (CF) sample. METHOD: Data was obtained from the 2013 Canadian Forces Mental Health Survey (CFMHS), and included a large representative sample of Canadian Regular Forces personnel (N = 6700). A series of univariate logistic regressions were conducted to test individual associations between past-year mental health status, insomnia, and potential confounds and SI. Mental health status included three groups: 0, 1, or two or more probable diagnoses of posttraumatic stress disorder (PTSD), major depressive disorder (MDD), generalized anxiety disorder (GAD), panic disorder (PD) and alcohol abuse/dependence. Stepwise multivariate logistic regression was used to assess the relationship between insomnia and SI with mental health status as a moderator. RESULTS: 40.8% of respondents reported experiencing insomnia. Both insomnia and number of mental health conditions incrementally increased the risk of SI. However, past-year mental health status was a significant moderator of this relationship, such that for CF personnel with either no (AOR = 1.61, 1.37-1.89) or only one past-year mental health condition (AOR = 1.39, 1.12-1.73), an incremental increase in insomnia was associated with an increased likelihood of SI. However, in personnel with two or more past-year mental health disorders, insomnia was no longer significantly associated with SI (AOR = 1.04, 0.81-1.33). CONCLUSIONS: Insomnia significantly increased the odds of SI, but only among individuals with no or one mental health condition. Findings highlight the importance of assessing insomnia among CF members in order to further suicide prevention efforts.


Asunto(s)
Personal Militar/psicología , Enfermedades Profesionales/psicología , Trastornos del Inicio y del Mantenimiento del Sueño/psicología , Ideación Suicida , Adolescente , Adulto , Alcoholismo/psicología , Trastornos de Ansiedad/psicología , Canadá , Trastorno Depresivo Mayor/psicología , Femenino , Encuestas Epidemiológicas , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Trastorno de Pánico/psicología , Factores de Riesgo , Trastornos por Estrés Postraumático/psicología , Adulto Joven
4.
J Comput Biol ; 8(2): 151-75, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11454303

RESUMEN

Different statistical measures of bias of oligonucleotide sequences in DNA sequences were compared, both by theoretical analysis and according to their abilities to predict the relative abundances of oligonucleotides in the genome of Escherichia coli. The expected frequency of an oligonucleotide calculated from a maximal order Markov model was shown to be a degenerate case of the expected frequency calculated from biases of all subwords arising when noncontiguous subwords exhibit no bias. Since (at least in E. coli) noncontiguous sequences exhibit significant bias, the total compositional bias approach is expected to represent biases in genomic sequences more faithfully than Markov approaches. In fact, the efficacy of statistics based on Markov analysis even at the highest order were inferior in predicting actual frequencies of oligonucleotides to methods that factored out biases of internal subwords with gaps. Using total compositional bias as a measure of relative abundance, tetranucleotide and hexanucleotide palindromes were found to be distributed differently from nonpalindromic sequences, with their means shifted somewhat towards underrepresentation. A subpopulation of palindromic hexanucleotides, however, was highly underrepresented, and this group consisted almost entirely of targets for Type II restriction enzymes found within strains of E. coli. Sites recognized by Type I endonucleases from related strains were not markedly biased, and with pentanucleotides, palindromic and nonpalindromic sequences had nearly identical distributions. The loss of restriction sites may be explained by the free transfer of plasmids encoding restriction enzymes and episodic selection for the presence of the enzymes.


Asunto(s)
Modelos Genéticos , Oligonucleótidos/genética , Composición de Base , Sesgo , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Desoxirribonucleasas de Localización Especificada Tipo I/metabolismo , Desoxirribonucleasas de Localización Especificada Tipo II/metabolismo , Escherichia coli/genética , Frecuencia de los Genes , Genoma Bacteriano , Cadenas de Markov , Modelos Estadísticos , Oligonucleótidos/metabolismo , Análisis de Secuencia de ADN/métodos
5.
Assessment ; 8(2): 221-36, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11428701

RESUMEN

This investigation explored the effect of posttraumatic stress disorder (PTSD) simulation on Minnesota Multiphasic Personality Inventory-2 (MMPI-2) responses, to detect malingered from genuine PTSD. Sixty-four adult PTSD outpatients at a child sexual abuse (CSA) survivor treatment program were compared with 85 adult college students instructed and trained to malinger PTSD. MMPI-2 overreporting indices examined were F, F-Fb, F-K, F(p), Ds2, O-S, OT, and FBS. A stepwise discriminant analysis identified F(p), F-K, and O-S as the best malingering predictors. A predictive discriminant analysis yielded good hit rates for the model, with impressive cross-validation results. Cutoff scores were assessed for the model's predictors. Clinical implications for detecting malingered PTSD using the MMPI-2 are discussed.


Asunto(s)
MMPI , Simulación de Enfermedad/diagnóstico , Trastornos por Estrés Postraumático/diagnóstico , Adulto , Diagnóstico Diferencial , Análisis Discriminante , Femenino , Humanos , Masculino , Persona de Mediana Edad , Encuestas y Cuestionarios
6.
Assessment ; 8(1): 75-84, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11310728

RESUMEN

This paper investigated subtypes of individuals trained and instructed to malinger Posttraumatic Stress Disorder (PTSD) through a cluster analysis of their Minnesota Multiphasic Personality Inventory-2 (MMPI-2) clinical and validity scales. Participants were 84 men and women college students at a community college in the southeastern United States. Two well fitting MMPI-2 cluster solutions were evaluated with discriminant analyses and multivariate analyses of variance (MANOVAs); a 2-cluster solution was deemed optimal. Significant between-cluster differences emerged in follow-up analyses on most of the content scales of the MMPI-2. Most demographic variables did not account for differences in cluster membership. Clusters differed in their reported clarity of the materials used to educate them about PTSD. Discriminant analyses yielded better correct classification rates than those from previous studies, when the more severely symptomatic cluster was compared with a sample of clinical combat-related PTSD veterans. Implications are considered in conducting future malingered PTSD investigations.


Asunto(s)
MMPI , Simulación de Enfermedad/diagnóstico , Simulación de Enfermedad/psicología , Trastornos por Estrés Postraumático/diagnóstico , Trastornos por Estrés Postraumático/psicología , Adolescente , Adulto , Anciano , Análisis por Conglomerados , Análisis Discriminante , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Encuestas y Cuestionarios
7.
Nucleic Acids Res ; 29(7): 1491-506, 2001 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-11266551

RESUMEN

From the characterization of enzyme activities and the analysis of genomic sequences, the complement of DNA methyltransferases (MTases) possessed by the cyanobacterium ANABAENA PCC 7120 has been deduced. ANABAENA has nine DNA MTases. Four are associated with Type II restriction enzymes (AVAI, AVAII, AVAIII and the newly recognized inactive AVAIV), and five are not. Of the latter, four may be classified as solitary MTases, those whose function lies outside of a restriction/modification system. The group is defined here based on biochemical and genetic characteristics. The four solitary MTases, DmtA/M.AVAVI, DmtB/M.AVAVII, DmtC/M. AVAVIII and DmtD/M.AVAIX, methylate at GATC, GGCC, CGATCG and rCCGGy, respectively. DmtB methylates cytosines at the N4 position, but its sequence is more similar to N6-adenine MTases than to cytosine-specific enzymes, indicating that it may have evolved from the former. The solitary MTases, appear to be of ancient origin within cyanobacteria, while the restriction MTases appear to have arrived by recent horizontal transfer as did five now inactive Type I restriction systems. One Mtase, M.AVAV, cannot reliably be classified as either a solitary or restriction MTase. It is structurally unusual and along with a few proteins of prokaryotic and eukaryotic origin defines a structural class of MTases distinct from all previously described.


Asunto(s)
Anabaena/genética , Metiltransferasas/genética , Proteínas Algáceas/genética , Secuencia de Aminoácidos , Anabaena/enzimología , Sitios de Unión , Clonación Molecular , ADN/química , ADN/genética , Metilasas de Modificación del ADN/genética , Orden Génico , Isoenzimas/genética , Datos de Secuencia Molecular , Filogenia , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido
8.
Photosynth Res ; 70(1): 85-106, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-16228364

RESUMEN

Nostoc punctiforme is a filamentous cyanobacterium with extensive phenotypic characteristics and a relatively large genome, approaching 10 Mb. The phenotypic characteristics include a photoautotrophic, diazotrophic mode of growth, but N. punctiforme is also facultatively heterotrophic; its vegetative cells have multiple developmental alternatives, including terminal differentiation into nitrogen-fixing heterocysts and transient differentiation into spore-like akinetes or motile filaments called hormogonia; and N. punctiforme has broad symbiotic competence with fungi and terrestrial plants, including bryophytes, gymnosperms and an angiosperm. The shotgun-sequencing phase of the N. punctiforme strain ATCC 29133 genome has been completed by the Joint Genome Institute. Annotation of an 8.9 Mb database yielded 7432 open reading frames, 45% of which encode proteins with known or probable known function and 29% of which are unique to N. punctiforme. Comparative analysis of the sequence indicates a genome that is highly plastic and in a state of flux, with numerous insertion sequences and multilocus repeats, as well as genes encoding transposases and DNA modification enzymes. The sequence also reveals the presence of genes encoding putative proteins that collectively define almost all characteristics of cyanobacteria as a group. N. punctiforme has an extensive potential to sense and respond to environmental signals as reflected by the presence of more than 400 genes encoding sensor protein kinases, response regulators and other transcriptional factors. The signal transduction systems and any of the large number of unique genes may play essential roles in the cell differentiation and symbiotic interaction properties of N. punctiforme.

9.
J Nerv Ment Dis ; 188(10): 708-13, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11048821

RESUMEN

This investigation examined differences in symptom patterns of two different trauma samples using the Minnesota Multiphasic Personality Inventory-2 (MMPI-2). MMPI-2s of 122 male combat veterans seeking outpatient treatment for combat-related PTSD were compared with those of 64 PTSD-diagnosed adults seeking outpatient treatment for the effects of child sexual abuse (CSA). We examined variables related to degree of health concerns, depression, somatization, anger and hostility, masculine-feminine traits, paranoid ideation, anxiety, difficulties thinking and concentrating, elevated mood, and social introversion, as well as test-taking attitude. MANOVAs revealed between-group differences on several variables. However, when analyses controlled for the effect of age, nearly all differences disappeared; the only remaining difference was in a scale measuring anger. Thus, it appears CSA survivors and combat veterans are much more similar than different in their clinical presentation on the MMPI-2. Conceptual issues in the assessment of PTSD are discussed.


Asunto(s)
Abuso Sexual Infantil/diagnóstico , MMPI/estadística & datos numéricos , Trastornos por Estrés Postraumático/diagnóstico , Adolescente , Adulto , Factores de Edad , Atención Ambulatoria , Análisis de Varianza , Niño , Abuso Sexual Infantil/estadística & datos numéricos , Diagnóstico Diferencial , Femenino , Humanos , Acontecimientos que Cambian la Vida , Masculino , Persona de Mediana Edad , Aceptación de la Atención de Salud , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Trastornos por Estrés Postraumático/epidemiología , Sobrevivientes/psicología , Sobrevivientes/estadística & datos numéricos , Veteranos/psicología , Veteranos/estadística & datos numéricos
10.
J Trauma Stress ; 13(1): 169-77, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10761181

RESUMEN

The relationship between coercion strategies used by perpetrators of childhood sexual abuse (CSA) and elevations of CSA survivors on the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) was investigated. Participants were 151 women survivors of CSA in outpatient treatment at a university-based community mental health center. Scores on the MMPI-2 clinical scales and the Keane posttraumatic stress disorder (PTSD) scale were examined. Main effects were found for promised or received rewards on several clinical scales and the PTSD scale of the MMPI-2, independent of the presence of force. Specifically, the presence of such rewards was associated with significantly higher levels of symptomatology on Paranoia (Pa), Psychasthenia (Pt), Schizophrenia (Sc), and PTSD (Pk). There were no main or interaction effects noted for the presence of actual or threatened force on any of the scales.


Asunto(s)
Abuso Sexual Infantil/psicología , Coerción , MMPI/estadística & datos numéricos , Sobrevida/psicología , Adolescente , Adulto , Niño , Femenino , Humanos , Persona de Mediana Edad , Motivación , Psicometría , Reproducibilidad de los Resultados
11.
J Pers Assess ; 75(3): 449-63, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11117156

RESUMEN

We attempted to cross-validate findings from a previous study (Elhai, Gold, Sellers, & Dorfman, in press) using a clinical sample of combat-related war veterans to distinguish genuine from malingered posttraumatic stress disorder (PTSD) on the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989). The MMPI-2 scores of 124 male combat war veterans at the PTSD outpatient treatment program of a Veterans Affairs Medical Center were compared with those of 84 adult college students instructed and trained to malinger PTSD. MMPI-2 overreporting variables examined were F, F-Fb, F-K, F(p), Ds2, O-S, OT, and FBS. A stepwise discriminant analysis identified F. F-Fb, F-K, Ds2, O-S, and OT as the best malingering predictors. A predictive discriminant analysis yielded good hit rates for the model with impressive cross-validation results. We assessed cutting scores for the predictors of the model. We discuss clinical implications for using the MMPI-2 to distinguish malingered PTSD from combat-related PTSD.


Asunto(s)
Trastornos de Combate/diagnóstico , Trastornos de Combate/psicología , MMPI/normas , Simulación de Enfermedad/diagnóstico , Simulación de Enfermedad/psicología , Veteranos/psicología , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Análisis Discriminante , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Sudeste de Estados Unidos , Estudiantes/psicología , Universidades
12.
Child Abuse Negl ; 23(7): 683-92, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10442833

RESUMEN

OBJECTIVE: The purpose of this study was to explore gender differences in symptomatology among sexual abuse survivors utilizing a standardized measure of specific symptom patterns, the Symptom Checklist 90-Revised (SCL-90-R). METHOD: Gender differences in symptomatology of adults sexually victimized as children were examined. Participants were 162 women and 25 men entering an outpatient treatment program for adult survivors of childhood sexual abuse (CSA) in a university-based community mental health center. Symptomatology was measured using the Symptom Checklist 90-Revised (SCL-90-R). RESULTS: Although no differences appeared when examining the raw data, the results changed dramatically once the data were converted into T-scores and epidemiological SCL-90-R gender differences were taken into account. The findings indicate that men exhibited significantly more interpersonal sensitivity, depression, anxiety, and phobic anxiety than women in relation to their respective normative samples. CONCLUSIONS: The use of nonclinical T-scores in this study allows for the interpretation that men survivors of childhood sexual abuse (CSA) have higher levels of symptomatology than women survivors when compared to their respective normative samples.


Asunto(s)
Abuso Sexual Infantil/psicología , Identidad de Género , Trastornos Mentales/psicología , Desarrollo de la Personalidad , Adolescente , Adulto , Trastornos de Ansiedad/diagnóstico , Trastornos de Ansiedad/psicología , Niño , Abuso Sexual Infantil/diagnóstico , Trastorno Depresivo/diagnóstico , Trastorno Depresivo/psicología , Femenino , Humanos , Masculino , Trastornos Mentales/diagnóstico , Persona de Mediana Edad , Inventario de Personalidad/estadística & datos numéricos , Trastornos Fóbicos/diagnóstico , Trastornos Fóbicos/psicología , Psicometría , Factores de Riesgo
13.
Child Abuse Negl ; 22(10): 1005-12, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9793723

RESUMEN

OBJECTIVE: The goal of this investigation was to examine similarities and differences in childhood sexual abuse (CSA) characteristics between men and women survivors in outpatient psychotherapy utilizing a substantial sample size of men, while examining an extensive range of abuse characteristics. METHOD: Abuse characteristics of 48 men from an outpatient treatment program for adult survivors of CSA in a university-based community mental health center were compared with those of 257 women from the same program. Data on abuse history were collected at admission or as soon thereafter as possible using a structured clinical interview with established reliability. RESULTS: Women were significantly more likely to have been sexually abused by a family member. Men were significantly more likely to report having oral sex performed upon them. Otherwise, no significant gender differences not attributable to anatomical differences (e.g., vaginal vs. anal intercourse) were found. CONCLUSIONS: The findings suggest that very few differences exist in the nature and extent of CSA reported by men and women. Thus CSA perpetrated on boys appears largely comparable in nature and extent to that committed against girls.


Asunto(s)
Abuso Sexual Infantil/estadística & datos numéricos , Hombres , Sobrevivientes/estadística & datos numéricos , Mujeres , Adolescente , Adulto , Niño , Abuso Sexual Infantil/terapia , Centros Comunitarios de Salud Mental , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicoterapia , Factores de Riesgo , Factores Sexuales , Sudeste de Estados Unidos , Encuestas y Cuestionarios
14.
J Bacteriol ; 179(6): 1998-2005, 1997 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9068647

RESUMEN

The efficiency of conjugal transfer of plasmids from Escherichia coli to the cyanobacterium Anabaena sp. strain PCC 7120 was quantitated as a function of the number of restriction sites for the restriction enzymes carried by the recipient. In addition to the previously recognized isoschizomers of AvaI and AvaII, PCC 7120 was found to possess an isoschizomer of AvaIII. Plasmids modified in E. coli with methylases that protect in vitro against restriction by the three enzymes were transferred with high efficiency, nearly independent of the number of restriction sites on the plasmid. Plasmids left unprotected against one of the three restriction enzymes were transferred with lower efficiencies. For low numbers of sites, the efficiency of conjugal transfer decreased as an exponential function of the number of unprotected sites. The methods presented may be used to increase the efficiency of conjugal transfer into restriction-competent bacteria.


Asunto(s)
Anabaena/genética , Conjugación Genética , Desoxirribonucleasas de Localización Especificada Tipo II/metabolismo , Plásmidos/genética , Anabaena/enzimología , Metilación de ADN , Metilasas de Modificación del ADN/genética , Metilasas de Modificación del ADN/metabolismo , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Escherichia coli/genética
15.
J Bacteriol ; 176(16): 5059-67, 1994 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8051018

RESUMEN

pEC22 is a small plasmid that encodes the restriction-modification system MR.EcoT22I. Restriction and functional analysis of the plasmid identified the positions of genes encoding that system. The plasmid is able to be conducted by conjugal plasmids, a process mediated by a transposon contained within pEC22. This cryptic transposon, called Tn5396, was isolated from pEC22 and partially sequenced. The sequence of Tn5396 is for the most part typical of transposons of the Tn3 family and is most similar to that of Tn1000. The transposon differs from closely related transposons in that it lacks well-conserved sequences in the inverted-repeat region and has an unusually long terminal inverted repeat. Consideration of regions of internal sequence similarity in this and other transposons in the Tn3 family supports a theory of the mechanism by which the ends of Tn3-like transposons may maintain substantial identity between their inverted repeats over the course of evolutionary time.


Asunto(s)
Conjugación Genética , Elementos Transponibles de ADN , Escherichia coli/genética , Plásmidos , Secuencia de Bases , Enzimas de Restricción-Modificación del ADN , Genes Bacterianos , Datos de Secuencia Molecular , Recombinación Genética
16.
FEMS Microbiol Lett ; 114(2): 179-84, 1993 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-8282186

RESUMEN

The strengths of several promoters were assessed in the cyanobacterium Anabaena PCC 7120 by fusing them to luxAB, encoding bacterial luciferase. Two promoters, Ptac and PpsbA, with sequences nearly identical to consensus Escherichia coli sigma 70 promoters, gave as high or higher expression than the strong Anabaena promoter, Prbc. Pnpt, the natural promoter driving expression of the kanamycin-resistance determinant from Tn5, was poorly expressed in Anabaena. The Lac repressor partially repressed expression from Ptac, permitting regulated expression in Anabaena after induction with isopropyl thiogalactoside to a level 4-5-fold higher than without inducer.


Asunto(s)
Anabaena/genética , Regulación Enzimológica de la Expresión Génica/genética , Luciferasas/biosíntesis , Regiones Promotoras Genéticas/genética , Anabaena/enzimología , Secuencia de Bases , Clonación Molecular/métodos , Datos de Secuencia Molecular
17.
Mol Microbiol ; 7(3): 441-5, 1993 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8459770

RESUMEN

The cyanobacterium Anabaena responds to nitrogen deprivation by producing heterocysts, cells specialized for nitrogen fixation, at well-spaced intervals along its filaments. The gene hepA, required for heterocyst maturation, is expressed in response to nitrogen deprivation, prior to visible differentiation. A spatial pattern of hepA expression indistinguishable from the eventual pattern of heterocysts was made visible by fusing the hepA promoter to luxAB, which encodes bacterial luciferase. Because the resulting signal did not greatly exceed instrumental background, T7 RNA polymerase was used to increase luminescence. The hepA promoter was fused to the gene for that polymerase, and a promoter recognized by that polymerase was fused to luxAB. Filaments containing these two fusions showed spaced luminescing cells many hours before differentiation became discernible morphologically.


Asunto(s)
Transportadoras de Casetes de Unión a ATP , Anabaena/genética , Proteínas Bacterianas/biosíntesis , Morfogénesis/genética , Transcripción Genética , Anabaena/citología , Proteínas Bacterianas/genética , ARN Polimerasas Dirigidas por ADN/genética , Amplificación de Genes , Regulación Bacteriana de la Expresión Génica , Luciferasas/genética , Plásmidos/genética , Regiones Promotoras Genéticas/genética , Proteínas Recombinantes de Fusión , Proteínas Virales
18.
EMBO J ; 9(10): 3379-88, 1990 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-2120040

RESUMEN

Depriving the cyanobacterium Anabaena of fixed nitrogen induces the differentiation of heterocysts at intervals along its filaments. To test whether the oxygen-deficient conditions believed to prevail within mature heterocysts are sufficient, in the absence of fixed nitrogen, to elicit the expression of nitrogenase, PnifHDK was fused transcriptionally to luxAB (encoding luciferase). Expression, monitored from individual cells as light emission, was localized (with a resolution of approximately 1 micron) to differentiated cells, whether or not oxygen was present. Anabaena PCC 7118 is a heterocystless mutant strain that is known to fix nitrogen when deprived of combined nitrogen under anaerobic conditions. Three lines of evidence indicate that the mutant has retained the ability to develop a pattern despite its inability to make heterocysts. First, morphologically distinct cells appear at nonrandom intervals when filaments are starved of nitrogen. Second, these cells, like heterocysts, have little or no phycocyanin-dependent fluorescence. Third, nitrogen-starved filaments fragment, with fragment lengths similar to the spacing normally seen between heterocysts. Expression of PnifHDK-luxAB was largely confined to differentiated cells in the mutant as in the wild-type strain. These results provide evidence for a causal relationship between development and transcriptional events in Anabaena.


Asunto(s)
Cianobacterias/genética , Genes , Nitrogenasa/genética , Aerobiosis , Anaerobiosis , Cianobacterias/enzimología , Cianobacterias/crecimiento & desarrollo , Cinética , Luz , Luciferasas/metabolismo , Nitrogenasa/metabolismo , Plásmidos , Proteínas Recombinantes de Fusión/metabolismo , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismo
19.
Gene ; 68(1): 119-38, 1988 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-2851487

RESUMEN

Several families of positive-selection cloning vectors were constructed, based on the principle of palindrome nonviability first used by Hagan and Warren [Gene 19 (1982) 147-151]. Each vector, derived from either pBR322 or RSF1010 (a broad-host-range plasmid), contains a long inverted repeat (2 x 366 to 2 x 1008 bp) ending in a symmetrical polylinker. Plasmids with long palindromes are not viable in most strains of Escherichia coli and in at least one Gram-positive bacterium. These palindrome-containing vectors therefore transform such strains at a very low frequency unless a DNA fragment is cloned within the polylinker at the center of the palindrome. Transformation by plasmids lacking an insert is reduced by two to four orders of magnitude. Such vectors can be propagated in a palindrome-tolerant strain; however, long symmetrical deletions then occur within the palindrome. To suppress the resulting deletion derivatives, vectors have been constructed so that an extensive deletion would remove the selectable marker. Alternatively, the vectors can be propagated in any strain of E. coli so long as the palindrome is interrupted by a nonpalindromic DNA fragment. We also present several symmetrical polylinkers and drug-resistance cassettes within the vectors. These components can be interchanged to make new positive-selection vectors as needed, and the cassettes are useful in insertional mutagenesis as well. A general method is described to convert virtually any small or medium-sized plasmid into a positive-selection vector.


Asunto(s)
Clonación Molecular , Resistencia a Medicamentos/genética , Escherichia coli/genética , Vectores Genéticos , Factores R , Secuencia de Bases , Deleción Cromosómica , Enzimas de Restricción del ADN , Genes Bacterianos , Modelos Genéticos , Datos de Secuencia Molecular , Plantas/genética , Regiones Promotoras Genéticas
20.
Nucleic Acids Res ; 16(4): 1563-75, 1988 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-2831502

RESUMEN

The McrA and McrB (modified cytosine restriction) systems of E. coli interfere with incoming DNA containing methylcytosine. DNA from many organisms, including all mammalian and plant DNA, is expected to be sensitive, and this could interfere with cloning experiments. The McrA and B phenotypes of a few strains have been reported previously (1-4). The Mcr phenotypes of 94 strains, primarily derived from E. coli K12, are tabulated here. We briefly review some evidence suggesting that McrB restriction of mouse-modified DNA does occur in vivo and does in fact interfere with cloning of specific mouse sequences.


Asunto(s)
Clonación Molecular , Citosina/análogos & derivados , Enzimas de Restricción del ADN/metabolismo , Escherichia coli/genética , 5-Metilcitosina , Escherichia coli/enzimología , Fenotipo , Especificidad de la Especie , Fagos T/genética
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